diff --git a/src/Buffer.cpp b/src/Buffer.cpp
index c9d6818df6..f4a02ca4e5 100644
--- a/src/Buffer.cpp
+++ b/src/Buffer.cpp
@@ -41,7 +41,6 @@
 #include "LaTeXFeatures.h"
 #include "LaTeX.h"
 #include "Layout.h"
-#include "Lexer.h"
 #include "LyXAction.h"
 #include "LyX.h"
 #include "LyXRC.h"
@@ -95,6 +94,7 @@
 #include "support/filetools.h"
 #include "support/gettext.h"
 #include "support/gzstream.h"
+#include "support/Lexer.h"
 #include "support/lstrings.h"
 #include "support/mutex.h"
 #include "support/os.h"
diff --git a/src/Buffer.h b/src/Buffer.h
index ee37098055..d9e7e325d4 100644
--- a/src/Buffer.h
+++ b/src/Buffer.h
@@ -39,7 +39,6 @@ class FuncRequest;
 class FuncStatus;
 class Inset;
 class InsetLabel;
-class Lexer;
 class Text;
 class LyXVC;
 class LaTeXFeatures;
@@ -67,6 +66,7 @@ namespace support {
 class DocFileName;
 class FileName;
 class FileNameList;
+class Lexer;
 } // namespace support
 
 namespace graphics {
@@ -226,7 +226,7 @@ public:
 //FIXME: The following function should be private
 //private:
 	/// read the header, returns number of unknown tokens
-	int readHeader(Lexer & lex);
+	int readHeader(support::Lexer & lex);
 
 	double fontScalingFactor() const;
 	/// check for active synctex support:
@@ -247,14 +247,14 @@ private:
 	/// Reads a file without header.
 	/// \param par if != 0 insert the file.
 	/// \return \c true if file is not completely read.
-	bool readDocument(Lexer &);
+	bool readDocument(support::Lexer &);
 	/// Try to extract the file from a version control container
 	/// before reading if the file cannot be found.
 	/// \sa LyXVC::file_not_found_hook
 	ReadStatus extractFromVC();
 	/// Reads the first tag of a LyX File and
 	/// returns the file format number.
-	ReadStatus parseLyXFormat(Lexer & lex, support::FileName const & fn,
+	ReadStatus parseLyXFormat(support::Lexer & lex, support::FileName const & fn,
 		int & file_format) const;
 	/// Convert the LyX file to the LYX_FORMAT using
 	/// the lyx2lyx script and returns the filename
diff --git a/src/BufferParams.cpp b/src/BufferParams.cpp
index 0d1600c5cf..1324aaac9e 100644
--- a/src/BufferParams.cpp
+++ b/src/BufferParams.cpp
@@ -33,7 +33,6 @@
 #include "LaTeXFeatures.h"
 #include "LaTeXFonts.h"
 #include "Font.h"
-#include "Lexer.h"
 #include "LyXRC.h"
 #include "OutputParams.h"
 #include "Spacing.h"
@@ -53,6 +52,7 @@
 #include "support/filetools.h"
 #include "support/gettext.h"
 #include "support/Length.h"
+#include "support/Lexer.h"
 #include "support/Messages.h"
 #include "support/mutex.h"
 #include "support/Package.h"
diff --git a/src/BufferParams.h b/src/BufferParams.h
index 489e053686..92c1418da1 100644
--- a/src/BufferParams.h
+++ b/src/BufferParams.h
@@ -31,7 +31,10 @@
 
 namespace lyx {
 
-namespace support { class FileName; }
+namespace support {
+class FileName;
+class Lexer;
+}
 
 class Author;
 class AuthorList;
@@ -48,7 +51,6 @@ class LaTeXFeatures;
 class LayoutFile;
 class LayoutFileIndex;
 class Length;
-class Lexer;
 class OutputParams;
 class otexstream;
 class PDFOptions;
@@ -79,7 +81,7 @@ public:
 	docstring B_(std::string const & l10n) const;
 
 	/// read a header token, if unrecognised, return it or an unknown class name
-	std::string readToken(Lexer & lex,
+	std::string readToken(support::Lexer & lex,
 		std::string const & token, ///< token to read.
 		support::FileName const & filename);
 
@@ -629,25 +631,25 @@ public:
 
 private:
 	///
-	void readPreamble(Lexer &);
+	void readPreamble(support::Lexer &);
 	///
-	void readDocumentMetadata(Lexer &);
+	void readDocumentMetadata(support::Lexer &);
 	///
-	void readLocalLayout(Lexer &, bool);
+	void readLocalLayout(support::Lexer &, bool);
 	///
-	void readLanguage(Lexer &);
+	void readLanguage(support::Lexer &);
 	///
-	void readGraphicsDriver(Lexer &);
+	void readGraphicsDriver(support::Lexer &);
 	///
-	void readBullets(Lexer &);
+	void readBullets(support::Lexer &);
 	///
-	void readBulletsLaTeX(Lexer &);
+	void readBulletsLaTeX(support::Lexer &);
 	///
-	void readModules(Lexer &);
+	void readModules(support::Lexer &);
 	///
-	void readRemovedModules(Lexer &);
+	void readRemovedModules(support::Lexer &);
 	///
-	void readIncludeonly(Lexer &);
+	void readIncludeonly(support::Lexer &);
 	/// A cache for the default flavors
 	typedef std::map<std::string, Flavor> DefaultFlavorCache;
 	///
diff --git a/src/BufferView.cpp b/src/BufferView.cpp
index 006211c15a..292b0f6a01 100644
--- a/src/BufferView.cpp
+++ b/src/BufferView.cpp
@@ -31,7 +31,6 @@
 #include "Intl.h"
 #include "Language.h"
 #include "LayoutFile.h"
-#include "Lexer.h"
 #include "LyX.h"
 #include "LyXAction.h"
 #include "lyxfind.h"
@@ -75,6 +74,7 @@
 #include "support/gettext.h"
 #include "support/lassert.h"
 #include "support/Length.h"
+#include "support/Lexer.h"
 #include "support/lstrings.h"
 #include "support/lyxlib.h"
 #include "support/types.h"
diff --git a/src/CiteEnginesList.cpp b/src/CiteEnginesList.cpp
index 6a1cef1a11..b12fa75edf 100644
--- a/src/CiteEnginesList.cpp
+++ b/src/CiteEnginesList.cpp
@@ -15,12 +15,12 @@
 #include "CiteEnginesList.h"
 
 #include "LaTeXFeatures.h"
-#include "Lexer.h"
 
 #include "support/debug.h"
 #include "support/FileName.h"
 #include "support/gettext.h"
 #include "support/filetools.h"
+#include "support/Lexer.h"
 #include "support/lstrings.h"
 #include "support/Translator.h"
 
diff --git a/src/CmdDef.cpp b/src/CmdDef.cpp
index 08cd7dd6a9..d813eba8e0 100644
--- a/src/CmdDef.cpp
+++ b/src/CmdDef.cpp
@@ -14,11 +14,11 @@
 
 #include "FuncRequest.h"
 #include "LyXAction.h"
-#include "Lexer.h"
 
 #include "support/debug.h"
 #include "support/FileName.h"
 #include "support/filetools.h"
+#include "support/Lexer.h"
 #include "support/lstrings.h"
 
 #include <string>
diff --git a/src/ConverterCache.cpp b/src/ConverterCache.cpp
index 0f4d03efb9..86c5764801 100644
--- a/src/ConverterCache.cpp
+++ b/src/ConverterCache.cpp
@@ -15,13 +15,13 @@
 #include "ConverterCache.h"
 
 #include "Format.h"
-#include "Lexer.h"
 #include "LyXRC.h"
 #include "Mover.h"
 
 #include "support/convert.h"
 #include "support/debug.h"
 #include "support/filetools.h"
+#include "support/Lexer.h"
 #include "support/lyxtime.h"
 #include "support/Package.h"
 
diff --git a/src/Counters.cpp b/src/Counters.cpp
index 114b18020b..703125f537 100644
--- a/src/Counters.cpp
+++ b/src/Counters.cpp
@@ -15,7 +15,6 @@
 
 #include "Counters.h"
 #include "Layout.h"
-#include "Lexer.h"
 
 #include "support/convert.h"
 #include "support/counter_reps.h"
@@ -23,6 +22,7 @@
 #include "support/docstring.h"
 #include "support/gettext.h"
 #include "support/lassert.h"
+#include "support/Lexer.h"
 #include "support/lstrings.h"
 
 #include <algorithm>
diff --git a/src/Counters.h b/src/Counters.h
index 5be4aca197..67a790fc0c 100644
--- a/src/Counters.h
+++ b/src/Counters.h
@@ -26,7 +26,8 @@
 namespace lyx {
 
 class Layout;
-class Lexer;
+
+namespace support { class Lexer; }
 
 /// This represents a single counter.
 class Counter {
@@ -38,7 +39,7 @@ public:
 		docstring const & lsa, docstring const & prettyformat,
 		docstring const & guiname);
 	/// \return true on success
-	bool read(Lexer & lex);
+	bool read(support::Lexer & lex);
 	///
 	void set(int v);
 	///
@@ -142,7 +143,7 @@ public:
 	/// \param makeNew whether to make a new counter if one
 	///        doesn't already exist
 	/// \return true on success
-	bool read(Lexer & lex, docstring const & name, bool makenew);
+	bool read(support::Lexer & lex, docstring const & name, bool makenew);
 	///
 	void set(docstring const & ctr, int val);
 	///
diff --git a/src/Encoding.cpp b/src/Encoding.cpp
index dab24b72dd..2dd3c9de8f 100644
--- a/src/Encoding.cpp
+++ b/src/Encoding.cpp
@@ -14,11 +14,10 @@
 
 #include "Encoding.h"
 
-#include "Lexer.h"
-
 #include "support/debug.h"
 #include "support/docstring.h"
 #include "support/gettext.h"
+#include "support/Lexer.h"
 #include "support/lstrings.h"
 #include "support/mutex.h"
 #include "support/textutils.h"
diff --git a/src/Font.cpp b/src/Font.cpp
index 7e0798d8ac..a4ae35727f 100644
--- a/src/Font.cpp
+++ b/src/Font.cpp
@@ -21,7 +21,6 @@
 #include "Encoding.h"
 #include "Language.h"
 #include "LaTeXFeatures.h"
-#include "Lexer.h"
 #include "LyXRC.h"
 #include "output_latex.h"
 #include "OutputParams.h"
@@ -31,6 +30,7 @@
 #include "support/convert.h"
 #include "support/debug.h"
 #include "support/gettext.h"
+#include "support/Lexer.h"
 #include "support/lstrings.h"
 
 #include <cstring>
diff --git a/src/FontInfo.cpp b/src/FontInfo.cpp
index 9f21bcc3d3..b6f45f88b5 100644
--- a/src/FontInfo.cpp
+++ b/src/FontInfo.cpp
@@ -17,13 +17,13 @@
 #include "FontInfo.h"
 
 #include "ColorSet.h"
-#include "Lexer.h"
 #include "LyXRC.h"
 
 #include "support/convert.h"
 #include "support/debug.h"
 #include "support/docstring.h"
 #include "support/gettext.h"
+#include "support/Lexer.h"
 #include "support/lstrings.h"
 
 #include <algorithm>
diff --git a/src/FontInfo.h b/src/FontInfo.h
index 3feefca662..bd0f125a7a 100644
--- a/src/FontInfo.h
+++ b/src/FontInfo.h
@@ -25,7 +25,7 @@
 
 namespace lyx {
 
-class Lexer;
+namespace support { class Lexer; }
 
 ///
 class FontInfo
@@ -257,7 +257,7 @@ void setLyXColor(std::string const &, FontInfo &);
 FontState setLyXMisc(std::string const &);
 
 /// Read a font specification from Lexer. Used for layout files.
-FontInfo lyxRead(Lexer &, FontInfo const & fi = sane_font);
+FontInfo lyxRead(support::Lexer &, FontInfo const & fi = sane_font);
 
 /// Write a font specification. Used for layout files.
 void lyxWrite(std::ostream &, FontInfo const &, std::string const &, int);
diff --git a/src/KeyMap.cpp b/src/KeyMap.cpp
index c34fe7eefb..8552d7cd44 100644
--- a/src/KeyMap.cpp
+++ b/src/KeyMap.cpp
@@ -17,13 +17,13 @@
 
 #include "KeySequence.h"
 #include "LyXAction.h"
-#include "Lexer.h"
 
 #include "support/debug.h"
 #include "support/docstream.h"
 #include "support/FileName.h"
 #include "support/filetools.h"
 #include "support/gettext.h"
+#include "support/Lexer.h"
 #include "support/lstrings.h"
 #include "support/TempFile.h"
 
diff --git a/src/LaTeXFonts.cpp b/src/LaTeXFonts.cpp
index c9d030e8c3..655d4f17e1 100644
--- a/src/LaTeXFonts.cpp
+++ b/src/LaTeXFonts.cpp
@@ -13,7 +13,6 @@
 #include "LaTeXFonts.h"
 
 #include "LaTeXFeatures.h"
-#include "Lexer.h"
 
 #include "frontends/alert.h"
 
@@ -23,6 +22,7 @@
 #include "support/FileName.h"
 #include "support/filetools.h"
 #include "support/gettext.h"
+#include "support/Lexer.h"
 #include "support/lstrings.h"
 
 
diff --git a/src/LaTeXFonts.h b/src/LaTeXFonts.h
index 8aae4ae31c..ce59b01d74 100644
--- a/src/LaTeXFonts.h
+++ b/src/LaTeXFonts.h
@@ -20,7 +20,7 @@
 
 namespace lyx {
 
-class Lexer;
+namespace support { class Lexer; }
 
 /// LaTeX Font definition
 class LaTeXFont {
@@ -96,9 +96,9 @@ public:
 	/// Return the actually used package
 	docstring const getUsedPackage(bool ot1, bool complete, bool nomath) const;
 	///
-	bool read(Lexer & lex);
+	bool read(support::Lexer & lex);
 	///
-	bool readFont(Lexer & lex);
+	bool readFont(support::Lexer & lex);
 private:
 	/// Return the preferred available package
 	std::string const getAvailablePackage(bool dryrun) const;
diff --git a/src/LaTeXPackages.cpp b/src/LaTeXPackages.cpp
index 0f4129eabe..9e0ffe5024 100644
--- a/src/LaTeXPackages.cpp
+++ b/src/LaTeXPackages.cpp
@@ -16,13 +16,12 @@
 
 #include "LaTeXPackages.h"
 
-#include "Lexer.h"
-
 #include "support/convert.h"
 #include "support/debug.h"
 #include "support/FileName.h"
 #include "support/filetools.h"
 #include "support/gettext.h"
+#include "support/Lexer.h"
 #include "support/lstrings.h"
 #include "support/Package.h"
 
diff --git a/src/Language.cpp b/src/Language.cpp
index 884d1a039b..60b897c134 100644
--- a/src/Language.cpp
+++ b/src/Language.cpp
@@ -18,7 +18,6 @@
 #include "BufferParams.h"
 #include "Encoding.h"
 #include "LaTeXFonts.h"
-#include "Lexer.h"
 #include "LyXRC.h"
 
 #include "support/debug.h"
@@ -26,6 +25,7 @@
 #include "support/FileName.h"
 #include "support/filetools.h"
 #include "support/lassert.h"
+#include "support/Lexer.h"
 #include "support/lstrings.h"
 #include "support/qstring_helpers.h"
 #include "support/Messages.h"
diff --git a/src/Language.h b/src/Language.h
index ad8badffbc..d8ef03a125 100644
--- a/src/Language.h
+++ b/src/Language.h
@@ -25,11 +25,13 @@
 
 namespace lyx {
 
-namespace support { class FileName; }
+namespace support {
+class FileName;
+class Lexer;
+}
 
 class BufferParams;
 class Encoding;
-class Lexer;
 
 ///
 class Language {
@@ -99,9 +101,9 @@ public:
 	/// This language corresponds to a translation of the GUI
 	bool hasGuiSupport() const { return has_gui_support_; }
 	///
-	bool read(Lexer & lex);
+	bool read(support::Lexer & lex);
 	///
-	bool readLanguage(Lexer & lex);
+	bool readLanguage(support::Lexer & lex);
 	///
 	typedef std::map<trivstring, trivdocstring> TranslationMap;
 	///
diff --git a/src/Layout.cpp b/src/Layout.cpp
index 8e54891fb9..50a4d05ac6 100644
--- a/src/Layout.cpp
+++ b/src/Layout.cpp
@@ -13,13 +13,13 @@
 #include <config.h>
 
 #include "Layout.h"
-#include "Lexer.h"
 #include "output_xhtml.h"
 #include "TextClass.h"
 
 #include "support/debug.h"
 #include "support/docstream.h"
 #include "support/lassert.h"
+#include "support/Lexer.h"
 #include "support/lstrings.h"
 #include "support/textutils.h"
 
diff --git a/src/Layout.h b/src/Layout.h
index 6581155007..0c0b4ae0ef 100644
--- a/src/Layout.h
+++ b/src/Layout.h
@@ -26,7 +26,8 @@
 
 namespace lyx {
 
-class Lexer;
+namespace support { class Lexer; }
+
 class TextClass;
 
 /* Fixed labels are printed flushright, manual labels flushleft.
@@ -58,23 +59,23 @@ public:
 	void setUnknown(bool unknown) { unknown_ = unknown; }
 	/// Reads a layout definition from file
 	/// \return true on success.
-	bool read(Lexer &, TextClass const &, bool validating = false);
+	bool read(support::Lexer &, TextClass const &, bool validating = false);
 	///
-	void readAlign(Lexer &);
+	void readAlign(support::Lexer &);
 	///
-	void readAlignPossible(Lexer &);
+	void readAlignPossible(support::Lexer &);
 	///
-	void readLabelType(Lexer &);
+	void readLabelType(support::Lexer &);
 	///
-	void readEndLabelType(Lexer &);
+	void readEndLabelType(support::Lexer &);
 	///
-	void readMargin(Lexer &);
+	void readMargin(support::Lexer &);
 	///
-	void readLatexType(Lexer &);
+	void readLatexType(support::Lexer &);
 	///
-	void readSpacing(Lexer &);
+	void readSpacing(support::Lexer &);
 	///
-	void readArgument(Lexer &, bool);
+	void readArgument(support::Lexer &, bool);
 	/// Write a layout definition in utf8 encoding
 	void write(std::ostream &) const;
 	///
@@ -439,7 +440,7 @@ public:
 private:
 	/// Reads a layout definition from file
 	/// \return true on success.
-	bool readIgnoreForcelocal(Lexer &, TextClass const &, bool validating);
+	bool readIgnoreForcelocal(support::Lexer &, TextClass const &, bool validating);
 	/// generates the default CSS for this layout
 	void makeDefaultCSS() const;
 	///
diff --git a/src/LayoutFile.cpp b/src/LayoutFile.cpp
index 7944ad73a2..3ed3676129 100644
--- a/src/LayoutFile.cpp
+++ b/src/LayoutFile.cpp
@@ -12,13 +12,13 @@
 #include <config.h>
 
 #include "LayoutFile.h"
-#include "Lexer.h"
 #include "TextClass.h"
 
 #include "support/debug.h"
 #include "support/FileName.h"
 #include "support/filetools.h"
 #include "support/lassert.h"
+#include "support/Lexer.h"
 #include "support/TempFile.h"
 
 #include <fstream>
diff --git a/src/LyXRC.cpp b/src/LyXRC.cpp
index 73aec189f3..9c8decab43 100644
--- a/src/LyXRC.cpp
+++ b/src/LyXRC.cpp
@@ -25,7 +25,6 @@
 #include "Format.h"
 #include "FuncCode.h"
 #include "FuncRequest.h"
-#include "Lexer.h"
 #include "LyX.h"
 #include "Mover.h"
 #include "SpellChecker.h"
@@ -36,6 +35,7 @@
 #include "support/environment.h"
 #include "support/FileName.h"
 #include "support/filetools.h"
+#include "support/Lexer.h"
 #include "support/lstrings.h"
 #include "support/os.h"
 #include "support/Package.h"
diff --git a/src/LyXRC.h b/src/LyXRC.h
index 039cf5658c..c437021c06 100644
--- a/src/LyXRC.h
+++ b/src/LyXRC.h
@@ -31,9 +31,10 @@
 
 namespace lyx {
 
-namespace support { class FileName; }
-
+namespace support {
+class FileName;
 class Lexer;
+}
 
 /// This contains the runtime configuration of LyX
 class LyXRC
@@ -212,7 +213,7 @@ private:
 		FormatMismatch
 	};
 	///
-	ReturnValues read(Lexer &, bool check_format);
+	ReturnValues read(support::Lexer &, bool check_format);
 public:
 	///
 	typedef std::set<std::string> CommandSet;
diff --git a/src/Makefile.am b/src/Makefile.am
index 86a90bb2bb..47a8e1ead5 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -147,7 +147,6 @@ SOURCEFILESCORE = \
 	LaTeXPackages.cpp \
 	LayoutFile.cpp \
 	LayoutModuleList.cpp \
-	Lexer.cpp \
 	LyX.cpp \
 	LyXAction.cpp \
 	lyxfind.cpp \
@@ -247,7 +246,6 @@ HEADERFILESCORE = \
 	LayoutEnums.h \
 	LayoutFile.h \
 	LayoutModuleList.h \
-	Lexer.h \
 	LyXAction.h \
 	lyxfind.h \
 	LyX.h \
diff --git a/src/ModuleList.cpp b/src/ModuleList.cpp
index d8fd34cc72..83f5a75940 100644
--- a/src/ModuleList.cpp
+++ b/src/ModuleList.cpp
@@ -14,12 +14,12 @@
 #include "ModuleList.h"
 
 #include "LaTeXFeatures.h"
-#include "Lexer.h"
 
 #include "support/debug.h"
 #include "support/FileName.h"
 #include "support/gettext.h"
 #include "support/filetools.h"
+#include "support/Lexer.h"
 #include "support/lstrings.h"
 
 #include <algorithm>
diff --git a/src/PDFOptions.cpp b/src/PDFOptions.cpp
index dc638f544d..c3d057eba8 100644
--- a/src/PDFOptions.cpp
+++ b/src/PDFOptions.cpp
@@ -15,7 +15,6 @@
 
 #include "Encoding.h"
 #include "LaTeXFeatures.h"
-#include "Lexer.h"
 #include "OutputParams.h"
 #include "texstream.h"
 
@@ -23,6 +22,7 @@
 #include "support/debug.h"
 #include "support/docstream.h"
 #include "support/docstring.h"
+#include "support/Lexer.h"
 #include "support/lstrings.h"
 
 #include <sstream>
diff --git a/src/PDFOptions.h b/src/PDFOptions.h
index 4ab0d9e3ad..e013566c14 100644
--- a/src/PDFOptions.h
+++ b/src/PDFOptions.h
@@ -16,10 +16,11 @@
 
 namespace lyx {
 
-class Lexer;
 class OutputParams;
 class otexstream;
 
+namespace support { class Lexer; }
+
 // FIXME UNICODE
 // Write functions need to use odostream instead of ostream before
 // we can use docstring instead of string.
@@ -37,7 +38,7 @@ public:
 	void writeLaTeX(OutputParams &, otexstream &,
 			bool hyperref_already_provided) const;
 	/// read tokens from lyx header
-	std::string readToken(Lexer &lex, std::string const & token);
+	std::string readToken(support::Lexer &lex, std::string const & token);
 	/// set implicit settings for hyperref
 	void clear();
 
diff --git a/src/ParagraphParameters.cpp b/src/ParagraphParameters.cpp
index 72b2286b12..32dc44900b 100644
--- a/src/ParagraphParameters.cpp
+++ b/src/ParagraphParameters.cpp
@@ -17,11 +17,11 @@
 #include "ParagraphParameters.h"
 
 #include "Layout.h"
-#include "Lexer.h"
 #include "Paragraph.h"
 
 #include "support/debug.h"
 #include "support/docstring.h"
+#include "support/Lexer.h"
 #include "support/lstrings.h"
 
 #include <sstream>
diff --git a/src/ParagraphParameters.h b/src/ParagraphParameters.h
index 07601e9e33..6f5b4f1b3f 100644
--- a/src/ParagraphParameters.h
+++ b/src/ParagraphParameters.h
@@ -25,9 +25,10 @@
 namespace lyx {
 
 class Layout;
-class Lexer;
 class Paragraph;
 
+namespace support { class Lexer; }
+
 
 ///
 class ParagraphParameters {
@@ -79,7 +80,7 @@ public:
 	void read (std::string const & str, bool merge = true);
 
 	/// read the parameters from a lex
-	void read(Lexer & lex, bool merge = true);
+	void read(support::Lexer & lex, bool merge = true);
 
 	///
 	void apply(ParagraphParameters const & params, Layout const & layout);
diff --git a/src/Text.cpp b/src/Text.cpp
index 1f9696de0d..55e150d6ac 100644
--- a/src/Text.cpp
+++ b/src/Text.cpp
@@ -45,7 +45,6 @@
 #include "Intl.h"
 #include "Language.h"
 #include "Layout.h"
-#include "Lexer.h"
 #include "LyX.h"
 #include "LyXAction.h"
 #include "lyxfind.h"
@@ -95,6 +94,7 @@
 #include "support/filetools.h"
 #include "support/gettext.h"
 #include "support/lassert.h"
+#include "support/Lexer.h"
 #include "support/limited_stack.h"
 #include "support/lstrings.h"
 #include "support/lyxtime.h"
diff --git a/src/Text.h b/src/Text.h
index 8dc066a161..9ef9c96260 100644
--- a/src/Text.h
+++ b/src/Text.h
@@ -33,10 +33,11 @@ class FuncRequest;
 class FuncStatus;
 class Inset;
 class InsetText;
-class Lexer;
 class Paragraph;
 class ParagraphParameters;
 
+namespace support { class Lexer; }
+
 /// This class encapsulates the main text data and operations in LyX.
 /// This is more or less the private implementation of InsetText.
 class Text {
@@ -299,7 +300,7 @@ public:
 	void write(std::ostream & os) const;
 	/// returns true if \end_document has not been read
 	/// insetPtr is the containing Inset
-	bool read(Lexer & lex, ErrorList & errorList,
+	bool read(support::Lexer & lex, ErrorList & errorList,
 	          InsetText * insetPtr);
 
 	/// delete double spaces, leading spaces, and empty paragraphs around old cursor.
@@ -381,10 +382,10 @@ private:
 	void pasteString(Cursor & cur, docstring const & str,
 			bool asParagraphs);
 	///
-	void readParToken(Paragraph & par, Lexer & lex, std::string const & token,
+	void readParToken(Paragraph & par, support::Lexer & lex, std::string const & token,
 		Font & font, Change & change, ErrorList & errorList);
 	///
-	void readParagraph(Paragraph & par, Lexer & lex, ErrorList & errorList);
+	void readParagraph(Paragraph & par, support::Lexer & lex, ErrorList & errorList);
 	/// Set Label Width string to all paragraphs of the same layout
 	/// and depth in a sequence.
 	void setLabelWidthStringToSequence(Cursor const & cur, docstring const & s);
diff --git a/src/TextClass.cpp b/src/TextClass.cpp
index f6ec875167..339d8c90cf 100644
--- a/src/TextClass.cpp
+++ b/src/TextClass.cpp
@@ -22,7 +22,6 @@
 #include "FloatList.h"
 #include "Layout.h"
 #include "LayoutFile.h"
-#include "Lexer.h"
 #include "ModuleList.h"
 
 #include "frontends/alert.h"
@@ -32,6 +31,7 @@
 #include "support/FileName.h"
 #include "support/filetools.h"
 #include "support/gettext.h"
+#include "support/Lexer.h"
 #include "support/lstrings.h"
 #include "support/os.h"
 #include "support/TempFile.h"
diff --git a/src/TextClass.h b/src/TextClass.h
index a4c758f339..2f42133491 100644
--- a/src/TextClass.h
+++ b/src/TextClass.h
@@ -35,12 +35,14 @@
 
 namespace lyx {
 
-namespace support { class FileName; }
+namespace support {
+class FileName;
+class Lexer;
+}
 
 class FloatList;
 class Layout;
 class LayoutFile;
-class Lexer;
 
 /// Based upon ideas in boost::noncopyable, inheriting from this
 /// class effectively makes the copy constructor protected but the
@@ -167,7 +169,7 @@ public:
 	///
 	ReturnValues read(std::string const & str, ReadType rt = MODULE);
 	///
-	ReturnValues read(Lexer & lex, ReadType rt = BASECLASS);
+	ReturnValues read(support::Lexer & lex, ReadType rt = BASECLASS);
 	/// validates the layout information passed in str
 	static ReturnValues validate(std::string const & str);
 	/// \return the conversion of \param str to the latest layout format
@@ -387,29 +389,29 @@ private:
 	/// Reads the layout file without running layout2layout.
 	ReturnValues readWithoutConv(support::FileName const & filename, ReadType rt);
 	/// \return true for success.
-	bool readStyle(Lexer &, Layout &, ReadType) const;
+	bool readStyle(support::Lexer &, Layout &, ReadType) const;
 	///
-	void readOutputType(Lexer &);
+	void readOutputType(support::Lexer &);
 	///
-	void readTitleType(Lexer &);
+	void readTitleType(support::Lexer &);
 	///
-	void readMaxCounter(Lexer &);
+	void readMaxCounter(support::Lexer &);
 	///
-	void readClassOptions(Lexer &);
+	void readClassOptions(support::Lexer &);
 	///
-	void readCharStyle(Lexer &, std::string const &);
+	void readCharStyle(support::Lexer &, std::string const &);
 	///
-	bool readFloat(Lexer &);
+	bool readFloat(support::Lexer &);
 	///
 	std::vector<CitationStyle> const & getCiteStyles(CiteEngineType const &) const;
 	///
-	bool readCiteEngine(Lexer &, ReadType, bool const add = false);
+	bool readCiteEngine(support::Lexer &, ReadType, bool const add = false);
 	///
-	int readCiteEngineType(Lexer &) const;
+	int readCiteEngineType(support::Lexer &) const;
 	///
-	bool readCiteFormat(Lexer &, ReadType);
+	bool readCiteFormat(support::Lexer &, ReadType);
 	///
-	bool readOutlinerName(Lexer &);
+	bool readOutlinerName(support::Lexer &);
 };
 
 
diff --git a/src/Trans.cpp b/src/Trans.cpp
index 5a03665684..28a05f05f9 100644
--- a/src/Trans.cpp
+++ b/src/Trans.cpp
@@ -13,13 +13,13 @@
 
 #include "Trans.h"
 
-#include "Lexer.h"
 #include "Text.h"
 
 #include "support/debug.h"
 #include "support/docstream.h"
 #include "support/FileName.h"
 #include "support/filetools.h"
+#include "support/Lexer.h"
 #include "support/lstrings.h"
 
 using namespace std;
diff --git a/src/Trans.h b/src/Trans.h
index c200bb9544..61a57b8e1e 100644
--- a/src/Trans.h
+++ b/src/Trans.h
@@ -26,9 +26,10 @@ namespace lyx {
 
 class Cursor;
 class Text;
-class Lexer;
 class TransManager;
 
+namespace support { class Lexer; }
+
 ///
 enum tex_accent {
 	///
@@ -149,7 +150,7 @@ private:
 	///
 	void freeKeymap();
 	///
-	int load(Lexer &);
+	int load(support::Lexer &);
 	///
 	docstring const & match(char_type c);
 	///
diff --git a/src/factory.cpp b/src/factory.cpp
index a465a55e86..0bea07b813 100644
--- a/src/factory.cpp
+++ b/src/factory.cpp
@@ -13,7 +13,6 @@
 #include "factory.h"
 
 #include "FuncRequest.h"
-#include "Lexer.h"
 #include "LyX.h"
 
 #include "insets/InsetBibitem.h"
@@ -65,6 +64,7 @@
 
 #include "support/debug.h"
 #include "support/ExceptionMessage.h"
+#include "support/Lexer.h"
 #include "support/lstrings.h"
 #include "support/unique_ptr.h"
 
diff --git a/src/factory.h b/src/factory.h
index ae2265e674..4ee9fb60f0 100644
--- a/src/factory.h
+++ b/src/factory.h
@@ -17,14 +17,14 @@ namespace lyx {
 class Buffer;
 class FuncRequest;
 class Inset;
-class Lexer;
 
+namespace support { class Lexer; }
 
 /// creates inset according to 'cmd'
 Inset * createInset(Buffer * buf, FuncRequest const & cmd);
 
 /// read inset from a file
-Inset * readInset(Lexer & lex, Buffer * buf);
+Inset * readInset(support::Lexer & lex, Buffer * buf);
 
 
 } // namespace lyx
diff --git a/src/frontends/qt/GuiApplication.cpp b/src/frontends/qt/GuiApplication.cpp
index a70ed358c5..516c970e71 100644
--- a/src/frontends/qt/GuiApplication.cpp
+++ b/src/frontends/qt/GuiApplication.cpp
@@ -46,7 +46,6 @@
 #include "KeyMap.h"
 #include "Language.h"
 #include "LaTeXPackages.h"
-#include "Lexer.h"
 #include "LyX.h"
 #include "LyXAction.h"
 #include "LyXRC.h"
@@ -69,6 +68,7 @@
 #include "support/ForkedCalls.h"
 #include "support/gettext.h"
 #include "support/lassert.h"
+#include "support/Lexer.h"
 #include "support/lstrings.h"
 #include "support/lyxalgo.h" // sorted
 #include "support/mute_warning.h"
diff --git a/src/frontends/qt/GuiLog.cpp b/src/frontends/qt/GuiLog.cpp
index 9ad1673de3..273dc25c95 100644
--- a/src/frontends/qt/GuiLog.cpp
+++ b/src/frontends/qt/GuiLog.cpp
@@ -16,12 +16,12 @@
 
 #include "GuiApplication.h"
 #include "qt_helpers.h"
-#include "Lexer.h"
 
 #include "frontends/Clipboard.h"
 
 #include "support/docstring.h"
 #include "support/gettext.h"
+#include "support/Lexer.h"
 #include "support/lstrings.h"
 
 #include <QTextBrowser>
diff --git a/src/frontends/qt/GuiParagraph.cpp b/src/frontends/qt/GuiParagraph.cpp
index b3c7349d20..d2fbd484f5 100644
--- a/src/frontends/qt/GuiParagraph.cpp
+++ b/src/frontends/qt/GuiParagraph.cpp
@@ -24,13 +24,12 @@
 #include "FuncRequest.h"
 #include "GuiView.h"
 #include "Layout.h"
-#include "Lexer.h"
 #include "Paragraph.h"
 #include "ParagraphParameters.h"
 #include "Spacing.h"
 
 #include "support/debug.h"
-#include "support/gettext.h"
+#include "support/Lexer.h"
 
 #include <QCheckBox>
 #include <QDialogButtonBox>
diff --git a/src/frontends/qt/GuiView.cpp b/src/frontends/qt/GuiView.cpp
index c44fbb3ed1..94a0a84be2 100644
--- a/src/frontends/qt/GuiView.cpp
+++ b/src/frontends/qt/GuiView.cpp
@@ -34,7 +34,6 @@
 #include "TocModel.h"
 
 #include "qt_helpers.h"
-#include "support/filetools.h"
 
 #include "frontends/alert.h"
 #include "frontends/KeySymbol.h"
@@ -56,7 +55,6 @@
 #include "KeySymbol.h"
 #include "Language.h"
 #include "LayoutFile.h"
-#include "Lexer.h"
 #include "LyXAction.h"
 #include "LyX.h"
 #include "LyXRC.h"
@@ -75,9 +73,11 @@
 #include "support/debug.h"
 #include "support/ExceptionMessage.h"
 #include "support/FileName.h"
-#include "support/gettext.h"
+#include "support/filetools.h"
 #include "support/ForkedCalls.h"
+#include "support/gettext.h"
 #include "support/lassert.h"
+#include "support/Lexer.h"
 #include "support/lstrings.h"
 #include "support/os.h"
 #include "support/Package.h"
diff --git a/src/frontends/qt/Menus.cpp b/src/frontends/qt/Menus.cpp
index 193e2478fa..a191073935 100644
--- a/src/frontends/qt/Menus.cpp
+++ b/src/frontends/qt/Menus.cpp
@@ -42,7 +42,6 @@
 #include "KeyMap.h"
 #include "Language.h"
 #include "Layout.h"
-#include "Lexer.h"
 #include "LyXAction.h"
 #include "LyX.h"
 #include "LyXRC.h"
@@ -64,12 +63,13 @@
 #include "insets/InsetInfo.h"
 #include "insets/InsetQuotes.h"
 
-#include "support/lassert.h"
 #include "support/convert.h"
 #include "support/debug.h"
 #include "support/docstring_list.h"
 #include "support/filetools.h"
 #include "support/gettext.h"
+#include "support/lassert.h"
+#include "support/Lexer.h"
 #include "support/lstrings.h"
 
 #include <QCursor>
diff --git a/src/frontends/qt/Menus.h b/src/frontends/qt/Menus.h
index 8166b45178..56875fb5cb 100644
--- a/src/frontends/qt/Menus.h
+++ b/src/frontends/qt/Menus.h
@@ -22,9 +22,10 @@ namespace lyx {
 
 class BufferView;
 class docstring_list;
-class Lexer;
 class FuncRequest;
 
+namespace support { class Lexer; }
+
 namespace frontend {
 
 class GuiView;
@@ -79,7 +80,7 @@ public:
 	Menu * menu(QString const & name, GuiView & view, bool keyboard = false);
 
 	///
-	void read(Lexer &);
+	void read(support::Lexer &);
 
 	///
 	void updateMenu(Menu * qmenu);
diff --git a/src/frontends/qt/Toolbars.cpp b/src/frontends/qt/Toolbars.cpp
index cf184ae9e2..a22c5aa589 100644
--- a/src/frontends/qt/Toolbars.cpp
+++ b/src/frontends/qt/Toolbars.cpp
@@ -15,12 +15,12 @@
 #include "Converter.h"
 #include "Format.h"
 #include "FuncRequest.h"
-#include "Lexer.h"
 #include "LyXAction.h"
 #include "qt_helpers.h"
 
 #include "support/debug.h"
 #include "support/gettext.h"
+#include "support/Lexer.h"
 #include "support/lstrings.h"
 
 #include <algorithm>
diff --git a/src/frontends/qt/Toolbars.h b/src/frontends/qt/Toolbars.h
index be621c9db8..e6989b183d 100644
--- a/src/frontends/qt/Toolbars.h
+++ b/src/frontends/qt/Toolbars.h
@@ -23,7 +23,8 @@
 namespace lyx {
 
 class FuncRequest;
-class Lexer;
+
+namespace support { class Lexer; }
 
 namespace frontend {
 
@@ -92,7 +93,7 @@ public:
 	Items items;
 
 	/// read a toolbar from the file
-	ToolbarInfo & read(Lexer &);
+	ToolbarInfo & read(support::Lexer &);
 
 private:
 	/// add toolbar item
@@ -140,10 +141,10 @@ public:
 	Infos::iterator end() { return toolbar_info_.end(); }
 
 	/// read toolbars from the file
-	void readToolbars(Lexer &);
+	void readToolbars(support::Lexer &);
 
 	/// read ui toolbar settings
-	void readToolbarSettings(Lexer &);
+	void readToolbarSettings(support::Lexer &);
 
 	///
 	ToolbarInfo const * info(std::string const & name) const;
diff --git a/src/insets/ExternalTemplate.cpp b/src/insets/ExternalTemplate.cpp
index e7eca8b274..67ea027ccb 100644
--- a/src/insets/ExternalTemplate.cpp
+++ b/src/insets/ExternalTemplate.cpp
@@ -13,10 +13,10 @@
 
 #include "ExternalTemplate.h"
 
-#include "Lexer.h"
 
 #include "support/debug.h"
 #include "support/filetools.h"
+#include "support/Lexer.h"
 #include "support/lstrings.h"
 #include "support/Package.h"
 #include "support/PathChanger.h"
diff --git a/src/insets/ExternalTemplate.h b/src/insets/ExternalTemplate.h
index e5b6755059..889dd563ce 100644
--- a/src/insets/ExternalTemplate.h
+++ b/src/insets/ExternalTemplate.h
@@ -19,9 +19,10 @@
 
 namespace lyx {
 
-namespace support { class FileName; }
-
+namespace support {
+class FileName;
 class Lexer;
+}
 
 enum PreviewMode {
 	PREVIEW_OFF = 0,
@@ -36,7 +37,7 @@ public:
 	/// We have to have default commands for safety reasons!
 	Template();
 	///
-	void readTemplate(Lexer &);
+	void readTemplate(support::Lexer &);
 	///
 	void dumpFormats(std::ostream &) const;
 
@@ -72,7 +73,7 @@ public:
 	public:
 		Format();
 		///
-		void readFormat(Lexer &);
+		void readFormat(support::Lexer &);
 
 		/// The text that should be inserted into the exported file
 		std::string product;
diff --git a/src/insets/Inset.h b/src/insets/Inset.h
index 2fa3e26234..04eb42ce73 100644
--- a/src/insets/Inset.h
+++ b/src/insets/Inset.h
@@ -56,7 +56,6 @@ class InsetTabular;
 class InsetText;
 class Language;
 class LaTeXFeatures;
-class Lexer;
 class MathAtom;
 class MetricsInfo;
 class PainterInfo;
@@ -68,7 +67,10 @@ class otexstream;
 
 namespace graphics { class PreviewLoader; }
 
-namespace support {class FileNameList; }
+namespace support {
+class FileNameList;
+class Lexer;
+}
 
 /// returns the InsetCode corresponding to the \c name.
 /// Eg, insetCode("branch") == BRANCH_CODE
@@ -501,7 +503,7 @@ public:
 	/// write inset in .lyx format
 	virtual void write(std::ostream &) const {}
 	/// read inset in .lyx format
-	virtual void read(Lexer &) {}
+	virtual void read(support::Lexer &) {}
 	/** Export the inset to LaTeX.
 	 *  Don't use a temporary stringstream if the final output is
 	 *  supposed to go to a file.
diff --git a/src/insets/InsetArgument.cpp b/src/insets/InsetArgument.cpp
index 89ed730b83..c4708c8d42 100644
--- a/src/insets/InsetArgument.cpp
+++ b/src/insets/InsetArgument.cpp
@@ -22,7 +22,6 @@
 #include "InsetList.h"
 #include "Language.h"
 #include "Layout.h"
-#include "Lexer.h"
 #include "ParIterator.h"
 #include "TexRow.h"
 #include "texstream.h"
@@ -33,12 +32,14 @@
 #include "support/debug.h"
 #include "support/docstream.h"
 #include "support/gettext.h"
+#include "support/Lexer.h"
 #include "support/lstrings.h"
 
 using namespace std;
 
 namespace lyx {
 
+using support::Lexer;
 
 InsetArgument::InsetArgument(Buffer * buf, string const & name)
     : InsetCollapsible(buf), name_(name), labelstring_(docstring()),
diff --git a/src/insets/InsetArgument.h b/src/insets/InsetArgument.h
index 34f4309cb0..a3dd7d05bf 100644
--- a/src/insets/InsetArgument.h
+++ b/src/insets/InsetArgument.h
@@ -68,7 +68,7 @@ public:
 	///
 	void write(std::ostream & os) const override;
 	///
-	void read(Lexer & lex) override;
+	void read(support::Lexer & lex) override;
 	///
 	bool neverIndent() const override { return true; }
 	///
diff --git a/src/insets/InsetBibitem.cpp b/src/insets/InsetBibitem.cpp
index 6336da32d4..343770e14d 100644
--- a/src/insets/InsetBibitem.cpp
+++ b/src/insets/InsetBibitem.cpp
@@ -26,7 +26,6 @@
 #include "InsetIterator.h"
 #include "InsetList.h"
 #include "Language.h"
-#include "Lexer.h"
 #include "output_xhtml.h"
 #include "Paragraph.h"
 #include "ParagraphList.h"
@@ -40,6 +39,7 @@
 #include "support/debug.h"
 #include "support/docstream.h"
 #include "support/gettext.h"
+#include "support/Lexer.h"
 #include "support/lstrings.h"
 #include "support/mutex.h"
 
diff --git a/src/insets/InsetBibitem.h b/src/insets/InsetBibitem.h
index 2a210e8c90..b9ce1aef81 100644
--- a/src/insets/InsetBibitem.h
+++ b/src/insets/InsetBibitem.h
@@ -51,7 +51,7 @@ public:
 	///
 	bool isLabeled() const override { return true; }
 	///
-	void read(Lexer & lex) override;
+	void read(support::Lexer & lex) override;
 	///
 	int plaintext(odocstringstream &, OutputParams const &,
 	              size_t max_length = INT_MAX) const override;
diff --git a/src/insets/InsetBox.cpp b/src/insets/InsetBox.cpp
index edfa6a569c..972ca20572 100644
--- a/src/insets/InsetBox.cpp
+++ b/src/insets/InsetBox.cpp
@@ -24,7 +24,6 @@
 #include "FuncStatus.h"
 #include "FuncRequest.h"
 #include "LaTeXFeatures.h"
-#include "Lexer.h"
 #include "MetricsInfo.h"
 #include "output_docbook.h"
 #include "output_xhtml.h"
@@ -36,6 +35,7 @@
 #include "support/docstream.h"
 #include "support/FileName.h"
 #include "support/gettext.h"
+#include "support/Lexer.h"
 #include "support/lstrings.h"
 #include "support/Translator.h"
 
diff --git a/src/insets/InsetBox.h b/src/insets/InsetBox.h
index f4a743667b..a5b71e5cda 100644
--- a/src/insets/InsetBox.h
+++ b/src/insets/InsetBox.h
@@ -29,7 +29,7 @@ public:
 	///
 	void write(std::ostream & os) const;
 	///
-	void read(Lexer & lex);
+	void read(support::Lexer & lex);
 
 	///
 	std::string type;
@@ -108,7 +108,7 @@ public:
 	///
 	void write(std::ostream &) const override;
 	///
-	void read(Lexer & lex) override;
+	void read(support::Lexer & lex) override;
 	///
 	void metrics(MetricsInfo &, Dimension &) const override;
 	///
diff --git a/src/insets/InsetBranch.cpp b/src/insets/InsetBranch.cpp
index 229e1bc37e..a86b934826 100644
--- a/src/insets/InsetBranch.cpp
+++ b/src/insets/InsetBranch.cpp
@@ -23,7 +23,6 @@
 #include "FuncStatus.h"
 #include "Inset.h"
 #include "LaTeXFeatures.h"
-#include "Lexer.h"
 #include "LyX.h"
 #include "output_docbook.h"
 #include "output_xhtml.h"
@@ -33,6 +32,7 @@
 #include "support/convert.h"
 #include "support/debug.h"
 #include "support/gettext.h"
+#include "support/Lexer.h"
 #include "support/lstrings.h"
 
 #include "frontends/alert.h"
@@ -45,6 +45,8 @@ using namespace std;
 
 namespace lyx {
 
+using support::Lexer;
+
 InsetBranch::InsetBranch(Buffer * buf, InsetBranchParams const & params)
 	: InsetCollapsible(buf, InsetText::DefaultLayout), params_(params)
 {}
diff --git a/src/insets/InsetBranch.h b/src/insets/InsetBranch.h
index 5098e70afb..58154701e3 100644
--- a/src/insets/InsetBranch.h
+++ b/src/insets/InsetBranch.h
@@ -26,7 +26,7 @@ public:
 	///
 	void write(std::ostream & os) const;
 	///
-	void read(Lexer & lex);
+	void read(support::Lexer & lex);
 	///
 	docstring branch;
 	///
@@ -65,7 +65,7 @@ private:
 	///
 	void write(std::ostream &) const override;
 	///
-	void read(Lexer & lex) override;
+	void read(support::Lexer & lex) override;
 	///
 	docstring const buttonLabel(BufferView const &) const override;
 	///
diff --git a/src/insets/InsetCollapsible.cpp b/src/insets/InsetCollapsible.cpp
index 519033e24a..d6c0461543 100644
--- a/src/insets/InsetCollapsible.cpp
+++ b/src/insets/InsetCollapsible.cpp
@@ -24,7 +24,6 @@
 #include "FuncRequest.h"
 #include "FuncStatus.h"
 #include "InsetLayout.h"
-#include "Lexer.h"
 #include "MetricsInfo.h"
 #include "TextClass.h"
 #include "TocBackend.h"
@@ -37,6 +36,7 @@
 #include "support/FileName.h"
 #include "support/gettext.h"
 #include "support/lassert.h"
+#include "support/Lexer.h"
 #include "support/lstrings.h"
 #include "support/Changer.h"
 #include "support/TempFile.h"
@@ -46,6 +46,8 @@ using namespace std;
 
 namespace lyx {
 
+using support::Lexer;
+
 InsetCollapsible::InsetCollapsible(Buffer * buf, InsetText::UsePlain ltype)
 	: InsetText(buf, ltype), status_(Open)
 {
diff --git a/src/insets/InsetCollapsible.h b/src/insets/InsetCollapsible.h
index 0f2711afba..22f846b89a 100644
--- a/src/insets/InsetCollapsible.h
+++ b/src/insets/InsetCollapsible.h
@@ -53,7 +53,7 @@ public:
 	///
 	docstring layoutName() const override { return from_ascii("Collapsible"); }
 	///
-	void read(Lexer &) override;
+	void read(support::Lexer &) override;
 	///
 	void write(std::ostream &) const override;
 
diff --git a/src/insets/InsetCommand.cpp b/src/insets/InsetCommand.cpp
index 50db6ddcdb..226d6193c9 100644
--- a/src/insets/InsetCommand.cpp
+++ b/src/insets/InsetCommand.cpp
@@ -21,7 +21,6 @@
 #include "FuncRequest.h"
 #include "FuncStatus.h"
 #include "InsetIterator.h"
-#include "Lexer.h"
 #include "LyX.h"
 #include "MetricsInfo.h"
 #include "texstream.h"
@@ -41,6 +40,7 @@
 #include "insets/InsetWrap.h"
 
 #include "support/debug.h"
+#include "support/Lexer.h"
 #include "support/lstrings.h"
 
 #include "frontends/Application.h"
diff --git a/src/insets/InsetCommand.h b/src/insets/InsetCommand.h
index 1605764450..d9ff9f8322 100644
--- a/src/insets/InsetCommand.h
+++ b/src/insets/InsetCommand.h
@@ -72,7 +72,7 @@ public:
 	///
 	void write(std::ostream & os) const override { p_.write(os); }
 	///
-	void read(Lexer & lex) override { p_.Read(lex, &buffer()); }
+	void read(support::Lexer & lex) override { p_.Read(lex, &buffer()); }
 	///
 	void doDispatch(Cursor & cur, FuncRequest & cmd) override;
 	///
diff --git a/src/insets/InsetCommandParams.cpp b/src/insets/InsetCommandParams.cpp
index 9c3552a4b7..523a4c81dc 100644
--- a/src/insets/InsetCommandParams.cpp
+++ b/src/insets/InsetCommandParams.cpp
@@ -30,7 +30,6 @@
 
 #include "Buffer.h"
 #include "Encoding.h"
-#include "Lexer.h"
 
 #include "frontends/alert.h"
 
@@ -38,9 +37,9 @@
 #include "support/docstream.h"
 #include "support/ExceptionMessage.h"
 #include "support/gettext.h"
-#include "support/lstrings.h"
-
 #include "support/lassert.h"
+#include "support/Lexer.h"
+#include "support/lstrings.h"
 
 #include <algorithm>
 #include <functional>
diff --git a/src/insets/InsetCommandParams.h b/src/insets/InsetCommandParams.h
index f05fb61ddc..a7cdd841b6 100644
--- a/src/insets/InsetCommandParams.h
+++ b/src/insets/InsetCommandParams.h
@@ -26,9 +26,10 @@
 namespace lyx {
 
 class Buffer;
-class Lexer;
 class OutputParams;
 
+namespace support { class Lexer; }
+
 class ParamInfo {
 public:
 	///
@@ -128,9 +129,9 @@ public:
 	///
 	InsetCode code() const { return insetCode_; }
 	/// Parse the command
-	void read(Lexer &);
+	void read(support::Lexer &);
 	///
-	void Read(Lexer &, Buffer const *);
+	void Read(support::Lexer &, Buffer const *);
 	///
 	void write(std::ostream &) const;
 	///
diff --git a/src/insets/InsetERT.cpp b/src/insets/InsetERT.cpp
index 00f497f031..e4b0e88022 100644
--- a/src/insets/InsetERT.cpp
+++ b/src/insets/InsetERT.cpp
@@ -18,7 +18,6 @@
 #include "FuncStatus.h"
 #include "InsetLayout.h"
 #include "Language.h"
-#include "Lexer.h"
 #include "xml.h"
 #include "ParagraphParameters.h"
 #include "Paragraph.h"
@@ -26,6 +25,7 @@
 
 #include "support/docstream.h"
 #include "support/gettext.h"
+#include "support/Lexer.h"
 #include "support/lstrings.h"
 #include "support/TempFile.h"
 #include "Encoding.h"
diff --git a/src/insets/InsetExternal.cpp b/src/insets/InsetExternal.cpp
index 0581d2e6fc..04c4c0de94 100644
--- a/src/insets/InsetExternal.cpp
+++ b/src/insets/InsetExternal.cpp
@@ -25,8 +25,6 @@
 #include "FuncStatus.h"
 #include "FuncRequest.h"
 #include "LaTeXFeatures.h"
-#include "Lexer.h"
-#include "LyX.h" // use_gui
 #include "LyXRC.h"
 #include "MetricsInfo.h"
 #include "output_latex.h"
@@ -46,6 +44,7 @@
 #include "support/filetools.h"
 #include "support/gettext.h"
 #include "support/lassert.h"
+#include "support/Lexer.h"
 #include "support/lstrings.h"
 #include "support/lyxlib.h"
 #include "support/TempFile.h"
diff --git a/src/insets/InsetExternal.h b/src/insets/InsetExternal.h
index ce71c94df3..28316d3be1 100644
--- a/src/insets/InsetExternal.h
+++ b/src/insets/InsetExternal.h
@@ -51,7 +51,7 @@ public:
 	InsetExternalParams();
 
 	void write(Buffer const &, std::ostream &) const;
-	bool read(Buffer const &, Lexer &);
+	bool read(Buffer const &, support::Lexer &);
 
 	/// The name of the tempfile used for manipulations.
 	support::FileName tempname() const { return tempname_(); }
@@ -141,7 +141,7 @@ public:
 	///
 	void write(std::ostream &) const override;
 	///
-	void read(Lexer & lex) override;
+	void read(support::Lexer & lex) override;
 	///
 	int plaintext(odocstringstream & ods, OutputParams const & op,
 	              size_t max_length = INT_MAX) const override;
diff --git a/src/insets/InsetFlex.cpp b/src/insets/InsetFlex.cpp
index 91c0b8cea1..2a8af67fae 100644
--- a/src/insets/InsetFlex.cpp
+++ b/src/insets/InsetFlex.cpp
@@ -20,12 +20,12 @@
 #include "FuncRequest.h"
 #include "FuncStatus.h"
 #include "Language.h"
-#include "Lexer.h"
 #include "ParIterator.h"
 #include "TextClass.h"
 
 #include "support/debug.h"
 #include "support/gettext.h"
+#include "support/Lexer.h"
 #include "support/lstrings.h"
 
 #include <ostream>
diff --git a/src/insets/InsetFloat.cpp b/src/insets/InsetFloat.cpp
index 9bef3ab258..8e024205e7 100644
--- a/src/insets/InsetFloat.cpp
+++ b/src/insets/InsetFloat.cpp
@@ -30,7 +30,6 @@
 #include "FuncRequest.h"
 #include "FuncStatus.h"
 #include "LaTeXFeatures.h"
-#include "Lexer.h"
 #include "xml.h"
 #include "output_docbook.h"
 #include "output_xhtml.h"
@@ -43,6 +42,7 @@
 #include "support/debug.h"
 #include "support/docstream.h"
 #include "support/gettext.h"
+#include "support/Lexer.h"
 #include "support/lstrings.h"
 
 #include "frontends/Application.h"
diff --git a/src/insets/InsetFloat.h b/src/insets/InsetFloat.h
index 50c698a43e..ada6add04a 100644
--- a/src/insets/InsetFloat.h
+++ b/src/insets/InsetFloat.h
@@ -30,7 +30,7 @@ public:
 	///
 	void write(std::ostream & os) const;
 	///
-	void read(Lexer & lex);
+	void read(support::Lexer & lex);
 	///
 	std::string type;
 	///
@@ -88,7 +88,7 @@ private:
 	///
 	void write(std::ostream & os) const override;
 	///
-	void read(Lexer & lex) override;
+	void read(support::Lexer & lex) override;
 	///
 	void validate(LaTeXFeatures & features) const override;
 	///
diff --git a/src/insets/InsetFloatList.cpp b/src/insets/InsetFloatList.cpp
index 3315d3b896..7075538f82 100644
--- a/src/insets/InsetFloatList.cpp
+++ b/src/insets/InsetFloatList.cpp
@@ -23,7 +23,6 @@
 #include "FuncRequest.h"
 #include "Language.h"
 #include "LaTeXFeatures.h"
-#include "Lexer.h"
 #include "Paragraph.h"
 #include "output_xhtml.h"
 #include "texstream.h"
@@ -32,6 +31,7 @@
 
 #include "support/debug.h"
 #include "support/gettext.h"
+#include "support/Lexer.h"
 #include "support/lstrings.h"
 
 #include <ostream>
diff --git a/src/insets/InsetFloatList.h b/src/insets/InsetFloatList.h
index ce6caa5770..21477f520d 100644
--- a/src/insets/InsetFloatList.h
+++ b/src/insets/InsetFloatList.h
@@ -36,7 +36,7 @@ public:
 	///
 	void write(std::ostream &) const override;
 	///
-	void read(Lexer &) override;
+	void read(support::Lexer &) override;
 	///
 	void latex(otexstream &, OutputParams const &) const override;
 	///
diff --git a/src/insets/InsetGraphics.cpp b/src/insets/InsetGraphics.cpp
index 62577f07db..b092ff44ff 100644
--- a/src/insets/InsetGraphics.cpp
+++ b/src/insets/InsetGraphics.cpp
@@ -63,7 +63,6 @@ TODO
 #include "InsetIterator.h"
 #include "LaTeX.h"
 #include "LaTeXFeatures.h"
-#include "Lexer.h"
 #include "MetricsInfo.h"
 #include "Mover.h"
 #include "output_docbook.h"
@@ -86,6 +85,7 @@ TODO
 #include "support/filetools.h"
 #include "support/gettext.h"
 #include "support/Length.h"
+#include "support/Lexer.h"
 #include "support/lyxlib.h"
 #include "support/lstrings.h"
 #include "support/os.h"
diff --git a/src/insets/InsetGraphics.h b/src/insets/InsetGraphics.h
index df2abc4b01..73b5625b11 100644
--- a/src/insets/InsetGraphics.h
+++ b/src/insets/InsetGraphics.h
@@ -68,7 +68,7 @@ public:
 	///
 	void write(std::ostream &) const override;
 	///
-	void read(Lexer & lex) override;
+	void read(support::Lexer & lex) override;
 	/** returns the number of rows (\n's) of generated tex code.
 	 #fragile == true# means, that the inset should take care about
 	 fragile commands by adding a #\protect# before.
diff --git a/src/insets/InsetGraphicsParams.cpp b/src/insets/InsetGraphicsParams.cpp
index 9f6ffbb901..ab2c9ff29c 100644
--- a/src/insets/InsetGraphicsParams.cpp
+++ b/src/insets/InsetGraphicsParams.cpp
@@ -15,7 +15,6 @@
 
 #include "Buffer.h"
 #include "LyX.h" // for use_gui
-#include "Lexer.h"
 #include "LyXRC.h"
 
 #include "graphics/epstools.h"
@@ -24,6 +23,7 @@
 #include "support/convert.h"
 #include "support/debug.h"
 #include "support/lyxlib.h"
+#include "support/Lexer.h"
 #include "support/lstrings.h"
 #include "support/Translator.h"
 
diff --git a/src/insets/InsetGraphicsParams.h b/src/insets/InsetGraphicsParams.h
index 1aa0b23d5b..dc6fde7a66 100644
--- a/src/insets/InsetGraphicsParams.h
+++ b/src/insets/InsetGraphicsParams.h
@@ -23,8 +23,8 @@
 namespace lyx {
 
 namespace graphics { class Params; }
+namespace support { class Lexer; }
 
-class Lexer;
 class Buffer;
 
 
@@ -77,7 +77,7 @@ public:
 	/// Buffer is needed to figure out if a figure is embedded.
 	void Write(std::ostream & os, Buffer const & buf) const;
 	/// If the token belongs to our parameters, read it.
-	bool Read(Lexer & lex, std::string const & token, Buffer const & buf,
+	bool Read(support::Lexer & lex, std::string const & token, Buffer const & buf,
 	          bool allowOrigin);
 	/// convert
 	// Only a subset of InsetGraphicsParams is needed for display purposes.
diff --git a/src/insets/InsetIPA.cpp b/src/insets/InsetIPA.cpp
index 7745b8d946..a6ee44032c 100644
--- a/src/insets/InsetIPA.cpp
+++ b/src/insets/InsetIPA.cpp
@@ -19,7 +19,6 @@
 #include "FuncRequest.h"
 #include "FuncStatus.h"
 #include "LaTeXFeatures.h"
-#include "Lexer.h"
 #include "MetricsInfo.h"
 #include "RenderPreview.h"
 #include "texstream.h"
@@ -28,6 +27,8 @@
 
 #include "graphics/PreviewImage.h"
 
+#include "support/Lexer.h"
+
 #include <sstream>
 
 using namespace std;
diff --git a/src/insets/InsetIPAMacro.cpp b/src/insets/InsetIPAMacro.cpp
index 2d4b1fb13c..4c72e9b702 100644
--- a/src/insets/InsetIPAMacro.cpp
+++ b/src/insets/InsetIPAMacro.cpp
@@ -21,7 +21,6 @@
 #include "FuncStatus.h"
 #include "InsetLayout.h"
 #include "LaTeXFeatures.h"
-#include "Lexer.h"
 #include "MetricsInfo.h"
 #include "xml.h"
 #include "texstream.h"
@@ -32,12 +31,15 @@
 #include "support/debug.h"
 #include "support/docstream.h"
 #include "support/gettext.h"
+#include "support/Lexer.h"
 #include "support/Translator.h"
 
 using namespace std;
 
 namespace lyx {
 
+using support::Lexer;
+
 namespace {
 
 typedef Translator<string, InsetIPADecoParams::Type> IPADecoTranslator;
diff --git a/src/insets/InsetIPAMacro.h b/src/insets/InsetIPAMacro.h
index dc1977f977..f871729c94 100644
--- a/src/insets/InsetIPAMacro.h
+++ b/src/insets/InsetIPAMacro.h
@@ -33,7 +33,7 @@ public:
 	///
 	void write(std::ostream & os) const;
 	///
-	void read(Lexer & lex);
+	void read(support::Lexer & lex);
 	///
 	Type type;
 };
@@ -70,7 +70,7 @@ private:
 	///
 	void write(std::ostream &) const override;
 	///
-	void read(Lexer & lex) override;
+	void read(support::Lexer & lex) override;
 	///
 	bool neverIndent() const override { return true; }
 	///
@@ -143,7 +143,7 @@ public:
 	///
 	void write(std::ostream &) const override;
 	/// Will not be used when lyxf3
-	void read(Lexer & lex) override;
+	void read(support::Lexer & lex) override;
 	///
 	void latex(otexstream &, OutputParams const &) const override;
 	///
diff --git a/src/insets/InsetIndex.cpp b/src/insets/InsetIndex.cpp
index 64bb398099..eb16a543ce 100644
--- a/src/insets/InsetIndex.cpp
+++ b/src/insets/InsetIndex.cpp
@@ -30,7 +30,6 @@
 #include "Paragraph.h"
 #include "LaTeX.h"
 #include "LaTeXFeatures.h"
-#include "Lexer.h"
 #include "LyX.h"
 #include "output_latex.h"
 #include "output_xhtml.h"
@@ -43,6 +42,7 @@
 #include "support/docstream.h"
 #include "support/FileName.h"
 #include "support/gettext.h"
+#include "support/Lexer.h"
 #include "support/lstrings.h"
 #include "support/Translator.h"
 
diff --git a/src/insets/InsetIndex.h b/src/insets/InsetIndex.h
index 860281b970..a1b7507a27 100644
--- a/src/insets/InsetIndex.h
+++ b/src/insets/InsetIndex.h
@@ -34,7 +34,7 @@ public:
 	///
 	void write(std::ostream & os) const;
 	///
-	void read(Lexer & lex);
+	void read(support::Lexer & lex);
 	///
 	docstring index;
 	///
@@ -72,7 +72,7 @@ private:
 	///
 	void write(std::ostream & os) const override;
 	///
-	void read(Lexer & lex) override;
+	void read(support::Lexer & lex) override;
 	///
 	void docbook(XMLStream &, OutputParams const &) const override;
 	///
diff --git a/src/insets/InsetIndexMacro.cpp b/src/insets/InsetIndexMacro.cpp
index 80ba766b53..cbd17a17e1 100644
--- a/src/insets/InsetIndexMacro.cpp
+++ b/src/insets/InsetIndexMacro.cpp
@@ -25,7 +25,6 @@
 #include "InsetList.h"
 #include "LaTeX.h"
 #include "LaTeXFeatures.h"
-#include "Lexer.h"
 #include "MetricsInfo.h"
 #include "xml.h"
 #include "texstream.h"
@@ -35,6 +34,7 @@
 #include "support/debug.h"
 #include "support/docstream.h"
 #include "support/gettext.h"
+#include "support/Lexer.h"
 #include "support/lstrings.h"
 #include "support/Translator.h"
 
diff --git a/src/insets/InsetIndexMacro.h b/src/insets/InsetIndexMacro.h
index 07109f8faf..b7ceed3fba 100644
--- a/src/insets/InsetIndexMacro.h
+++ b/src/insets/InsetIndexMacro.h
@@ -35,7 +35,7 @@ public:
 	///
 	void write(std::ostream & os) const;
 	///
-	void read(Lexer & lex);
+	void read(support::Lexer & lex);
 	///
 	Type type;
 };
@@ -76,7 +76,7 @@ private:
 	///
 	void write(std::ostream &) const override;
 	///
-	void read(Lexer & lex) override;
+	void read(support::Lexer & lex) override;
 	///
 	bool neverIndent() const override { return true; }
 	/// We do not output anything directly to the stream
diff --git a/src/insets/InsetInfo.cpp b/src/insets/InsetInfo.cpp
index df83f96b98..cfb5b7eafc 100644
--- a/src/insets/InsetInfo.cpp
+++ b/src/insets/InsetInfo.cpp
@@ -30,7 +30,6 @@
 #include "LyXAction.h"
 #include "LyXRC.h"
 #include "LyXVC.h"
-#include "Lexer.h"
 #include "output_docbook.h"
 #include "Paragraph.h"
 #include "ParIterator.h"
@@ -49,6 +48,7 @@
 #include "support/filetools.h"
 #include "support/gettext.h"
 #include "support/Length.h"
+#include "support/Lexer.h"
 #include "support/Messages.h"
 #include "support/lstrings.h"
 #include "support/qstring_helpers.h"
diff --git a/src/insets/InsetInfo.h b/src/insets/InsetInfo.h
index 9af4d2fe4d..e0cf7585b3 100644
--- a/src/insets/InsetInfo.h
+++ b/src/insets/InsetInfo.h
@@ -178,7 +178,7 @@ public:
 	///
 	bool hasSettings() const override { return true; }
 	///
-	void read(Lexer & lex) override;
+	void read(support::Lexer & lex) override;
 	///
 	void write(std::ostream & os) const override;
 	///
diff --git a/src/insets/InsetLayout.cpp b/src/insets/InsetLayout.cpp
index 8e5ed651cf..7a0c61211e 100644
--- a/src/insets/InsetLayout.cpp
+++ b/src/insets/InsetLayout.cpp
@@ -15,10 +15,10 @@
 #include "InsetLayout.h"
 
 #include "ColorSet.h"
-#include "Lexer.h"
 #include "TextClass.h"
 
 #include "support/debug.h"
+#include "support/Lexer.h"
 #include "support/lstrings.h"
 #include "support/textutils.h"
 
diff --git a/src/insets/InsetLayout.h b/src/insets/InsetLayout.h
index 6700100252..1d25dea046 100644
--- a/src/insets/InsetLayout.h
+++ b/src/insets/InsetLayout.h
@@ -24,9 +24,9 @@
 
 namespace lyx {
 
-class Lexer;
 class TextClass;
 
+namespace support { class Lexer; }
 
 enum class InsetDecoration : int {
 	CLASSIC,
@@ -57,7 +57,7 @@ public:
 	///
 	InsetLayout() { labelfont_.setColor(Color_insetlabel); }
 	///
-	bool read(Lexer & lexrc, TextClass const & tclass,
+	bool read(support::Lexer & lexrc, TextClass const & tclass,
 			bool validating = false);
 	///
 	docstring name() const { return name_; }
@@ -266,7 +266,7 @@ private:
 	///
 	std::string defaultCSSClass() const;
 	///
-	void readArgument(Lexer &);
+	void readArgument(support::Lexer &);
 	///
 	docstring name_ = from_ascii("undefined");
 	/**
diff --git a/src/insets/InsetListings.cpp b/src/insets/InsetListings.cpp
index 8268cebd68..24c8a21a63 100644
--- a/src/insets/InsetListings.cpp
+++ b/src/insets/InsetListings.cpp
@@ -25,7 +25,6 @@
 #include "InsetLayout.h"
 #include "Language.h"
 #include "LaTeXFeatures.h"
-#include "Lexer.h"
 #include "output_latex.h"
 #include "output_docbook.h"
 #include "output_xhtml.h"
@@ -35,6 +34,7 @@
 #include "support/debug.h"
 #include "support/docstream.h"
 #include "support/gettext.h"
+#include "support/Lexer.h"
 #include "support/lstrings.h"
 #include "support/lassert.h"
 
diff --git a/src/insets/InsetListings.h b/src/insets/InsetListings.h
index c72865cd90..df4d1e422e 100644
--- a/src/insets/InsetListings.h
+++ b/src/insets/InsetListings.h
@@ -52,7 +52,7 @@ private:
 	///
 	void write(std::ostream & os) const override;
 	///
-	void read(Lexer & lex) override;
+	void read(support::Lexer & lex) override;
 	///
 	void latex(otexstream &, OutputParams const &) const override;
 	///
diff --git a/src/insets/InsetListingsParams.cpp b/src/insets/InsetListingsParams.cpp
index e017d52352..2ce8f2719a 100644
--- a/src/insets/InsetListingsParams.cpp
+++ b/src/insets/InsetListingsParams.cpp
@@ -13,11 +13,10 @@
 
 #include "InsetListingsParams.h"
 
-#include "support/Length.h"
-#include "Lexer.h"
-
 #include "support/convert.h"
 #include "support/gettext.h"
+#include "support/Length.h"
+#include "support/Lexer.h"
 #include "support/lstrings.h"
 #include "support/textutils.h"
 
diff --git a/src/insets/InsetListingsParams.h b/src/insets/InsetListingsParams.h
index 90c5adb763..29240e8194 100644
--- a/src/insets/InsetListingsParams.h
+++ b/src/insets/InsetListingsParams.h
@@ -31,7 +31,7 @@ public:
 	void write(std::ostream &) const;
 
 	/// read parameters from an ostream
-	void read(Lexer &);
+	void read(support::Lexer &);
 
 	/// valid parameter string
 	std::string params(std::string const & sep=",") const;
diff --git a/src/insets/InsetNewline.cpp b/src/insets/InsetNewline.cpp
index ecfacf47ce..38898c8ecd 100644
--- a/src/insets/InsetNewline.cpp
+++ b/src/insets/InsetNewline.cpp
@@ -17,7 +17,6 @@
 #include "Dimension.h"
 #include "FuncRequest.h"
 #include "FuncStatus.h"
-#include "Lexer.h"
 #include "MetricsInfo.h"
 #include "output_docbook.h"
 #include "output_xhtml.h"
@@ -30,11 +29,14 @@
 #include "support/debug.h"
 #include "support/docstream.h"
 #include "support/docstring.h"
+#include "support/Lexer.h"
 
 using namespace std;
 
 namespace lyx {
 
+using support::Lexer;
+
 InsetNewline::InsetNewline() : Inset(nullptr)
 {}
 
diff --git a/src/insets/InsetNewline.h b/src/insets/InsetNewline.h
index c85a97df66..36cfe7390a 100644
--- a/src/insets/InsetNewline.h
+++ b/src/insets/InsetNewline.h
@@ -32,7 +32,7 @@ public:
 	///
 	void write(std::ostream & os) const;
 	///
-	void read(Lexer & lex);
+	void read(support::Lexer & lex);
 	///
 	Kind kind;
 };
@@ -69,7 +69,7 @@ private:
 	///
 	docstring xhtml(XMLStream &, OutputParams const &) const override;
 	///
-	void read(Lexer & lex) override;
+	void read(support::Lexer & lex) override;
 	///
 	void write(std::ostream & os) const override;
 	/// is this equivalent to a space (which is BTW different from
diff --git a/src/insets/InsetNewpage.cpp b/src/insets/InsetNewpage.cpp
index da94452632..caac17e27c 100644
--- a/src/insets/InsetNewpage.cpp
+++ b/src/insets/InsetNewpage.cpp
@@ -16,7 +16,6 @@
 #include "Cursor.h"
 #include "FuncRequest.h"
 #include "FuncStatus.h"
-#include "Lexer.h"
 #include "MetricsInfo.h"
 #include "xml.h"
 #include "texstream.h"
@@ -30,13 +29,15 @@
 #include "support/docstring.h"
 #include "support/docstream.h"
 #include "support/gettext.h"
+#include "support/Lexer.h"
 
 using namespace std;
 
-
 namespace lyx {
 
-	InsetNewpage::InsetNewpage() : Inset(nullptr)
+using support::Lexer;
+
+InsetNewpage::InsetNewpage() : Inset(nullptr)
 {}
 
 
diff --git a/src/insets/InsetNewpage.h b/src/insets/InsetNewpage.h
index d086276df2..80fee2ffc9 100644
--- a/src/insets/InsetNewpage.h
+++ b/src/insets/InsetNewpage.h
@@ -38,7 +38,7 @@ public:
 	///
 	void write(std::ostream & os) const;
 	///
-	void read(Lexer & lex);
+	void read(support::Lexer & lex);
 	///
 	Kind kind;
 };
@@ -72,7 +72,7 @@ private:
 	///
 	docstring xhtml(XMLStream &, OutputParams const &) const override;
 	///
-	void read(Lexer & lex) override;
+	void read(support::Lexer & lex) override;
 	///
 	void write(std::ostream & os) const override;
 	///
diff --git a/src/insets/InsetNote.cpp b/src/insets/InsetNote.cpp
index b12b755fba..7eed0ed9cc 100644
--- a/src/insets/InsetNote.cpp
+++ b/src/insets/InsetNote.cpp
@@ -25,7 +25,6 @@
 #include "FuncStatus.h"
 #include "InsetLayout.h"
 #include "LaTeXFeatures.h"
-#include "Lexer.h"
 #include "LyXRC.h"
 #include "output_docbook.h"
 #include "output_latex.h"
@@ -33,6 +32,7 @@
 #include "support/debug.h"
 #include "support/docstream.h"
 #include "support/gettext.h"
+#include "support/Lexer.h"
 #include "support/lstrings.h"
 #include "support/Translator.h"
 
@@ -45,6 +45,8 @@ using namespace std;
 
 namespace lyx {
 
+using support::Lexer;
+
 namespace {
 
 typedef Translator<string, InsetNoteParams::Type> NoteTranslator;
diff --git a/src/insets/InsetNote.h b/src/insets/InsetNote.h
index 94a07906e5..25e91f88eb 100644
--- a/src/insets/InsetNote.h
+++ b/src/insets/InsetNote.h
@@ -30,7 +30,7 @@ public:
 	///
 	void write(std::ostream & os) const;
 	///
-	void read(Lexer & lex);
+	void read(support::Lexer & lex);
 	///
 	Type type;
 };
@@ -71,7 +71,7 @@ private:
 	///
 	void write(std::ostream &) const override;
 	///
-	void read(Lexer & lex) override;
+	void read(support::Lexer & lex) override;
 	/// show the note dialog
 	bool showInsetDialog(BufferView * bv) const override;
 	///
diff --git a/src/insets/InsetPhantom.cpp b/src/insets/InsetPhantom.cpp
index d1a25f6a70..968d8f0337 100644
--- a/src/insets/InsetPhantom.cpp
+++ b/src/insets/InsetPhantom.cpp
@@ -22,7 +22,6 @@
 #include "FuncRequest.h"
 #include "FuncStatus.h"
 #include "LaTeXFeatures.h"
-#include "Lexer.h"
 #include "MetricsInfo.h"
 #include "texstream.h"
 #include "TextClass.h"
@@ -34,6 +33,7 @@
 
 #include "frontends/Application.h"
 #include "frontends/FontMetrics.h"
+#include "support/Lexer.h"
 #include "frontends/Painter.h"
 
 #include <algorithm>
@@ -43,6 +43,8 @@ using namespace std;
 
 namespace lyx {
 
+using support::Lexer;
+
 namespace {
 
 typedef Translator<string, InsetPhantomParams::Type> PhantomTranslator;
diff --git a/src/insets/InsetPhantom.h b/src/insets/InsetPhantom.h
index 72281df2ae..57f08102ba 100644
--- a/src/insets/InsetPhantom.h
+++ b/src/insets/InsetPhantom.h
@@ -30,7 +30,7 @@ public:
 	///
 	void write(std::ostream & os) const;
 	///
-	void read(Lexer & lex);
+	void read(support::Lexer & lex);
 	///
 	Type type;
 };
@@ -66,7 +66,7 @@ private:
 	///
 	void write(std::ostream &) const override;
 	///
-	void read(Lexer & lex) override;
+	void read(support::Lexer & lex) override;
 	///
 	void setButtonLabel() override;
 	/// show the phantom dialog
diff --git a/src/insets/InsetQuotes.cpp b/src/insets/InsetQuotes.cpp
index 46b8ef11ae..8d6caf1e5e 100644
--- a/src/insets/InsetQuotes.cpp
+++ b/src/insets/InsetQuotes.cpp
@@ -24,7 +24,6 @@
 #include "FuncRequest.h"
 #include "Language.h"
 #include "LaTeXFeatures.h"
-#include "Lexer.h"
 #include "LyXRC.h"
 #include "MetricsInfo.h"
 #include "Paragraph.h"
@@ -39,6 +38,7 @@
 #include "support/docstring.h"
 #include "support/docstream.h"
 #include "support/gettext.h"
+#include "support/Lexer.h"
 #include "support/lstrings.h"
 #include "support/textutils.h"
 
diff --git a/src/insets/InsetQuotes.h b/src/insets/InsetQuotes.h
index 2eeb5fa866..13bd8ea124 100644
--- a/src/insets/InsetQuotes.h
+++ b/src/insets/InsetQuotes.h
@@ -143,7 +143,7 @@ public:
 	///
 	void write(std::ostream &) const override;
 	///
-	void read(Lexer & lex) override;
+	void read(support::Lexer & lex) override;
 	///
 	bool getStatus(Cursor &, FuncRequest const &, FuncStatus &) const override;
 	///
diff --git a/src/insets/InsetScript.cpp b/src/insets/InsetScript.cpp
index c1f8da1e82..b588f4283e 100644
--- a/src/insets/InsetScript.cpp
+++ b/src/insets/InsetScript.cpp
@@ -22,7 +22,6 @@
 #include "FuncRequest.h"
 #include "FuncStatus.h"
 #include "LaTeXFeatures.h"
-#include "Lexer.h"
 #include "LyXAction.h"
 #include "MetricsInfo.h"
 #include "output_docbook.h"
@@ -32,6 +31,7 @@
 
 #include "support/docstream.h"
 #include "support/gettext.h"
+#include "support/Lexer.h"
 #include "support/lstrings.h"
 #include "support/Translator.h"
 
@@ -45,6 +45,8 @@ using namespace std;
 
 namespace lyx {
 
+using support::Lexer;
+
 namespace {
 
 typedef Translator<string, InsetScriptParams::Type> ScriptTranslator;
diff --git a/src/insets/InsetScript.h b/src/insets/InsetScript.h
index 1a008a9888..eab074b1e2 100644
--- a/src/insets/InsetScript.h
+++ b/src/insets/InsetScript.h
@@ -30,7 +30,7 @@ public:
 	///
 	void write(std::ostream & os) const;
 	///
-	void read(Lexer & lex);
+	void read(support::Lexer & lex);
 	///
 	int shift(FontInfo const & font) const;
 	///
@@ -87,7 +87,7 @@ public:
 	///
 	void write(std::ostream &) const override;
 	///
-	void read(Lexer & lex) override;
+	void read(support::Lexer & lex) override;
 	///
 	bool forcePlainLayout(idx_type = 0) const override { return true; }
 	///
diff --git a/src/insets/InsetSeparator.cpp b/src/insets/InsetSeparator.cpp
index 218172c87a..765fa93933 100644
--- a/src/insets/InsetSeparator.cpp
+++ b/src/insets/InsetSeparator.cpp
@@ -16,7 +16,6 @@
 #include "Dimension.h"
 #include "FuncRequest.h"
 #include "FuncStatus.h"
-#include "Lexer.h"
 #include "MetricsInfo.h"
 #include "output_docbook.h"
 #include "output_xhtml.h"
@@ -29,12 +28,15 @@
 #include "support/debug.h"
 #include "support/docstream.h"
 #include "support/docstring.h"
+#include "support/Lexer.h"
 
 using namespace std;
 using namespace lyx::frontend;
 
 namespace lyx {
 
+using support::Lexer;
+
 InsetSeparator::InsetSeparator() : Inset(nullptr)
 {}
 
diff --git a/src/insets/InsetSeparator.h b/src/insets/InsetSeparator.h
index b824214ae7..dba716c6aa 100644
--- a/src/insets/InsetSeparator.h
+++ b/src/insets/InsetSeparator.h
@@ -31,7 +31,7 @@ public:
 	///
 	void write(std::ostream & os) const;
 	///
-	void read(Lexer & lex);
+	void read(support::Lexer & lex);
 	///
 	Kind kind;
 };
@@ -85,7 +85,7 @@ private:
 	///
 	docstring xhtml(XMLStream &, OutputParams const &) const override;
 	///
-	void read(Lexer & lex) override;
+	void read(support::Lexer & lex) override;
 	///
 	void write(std::ostream & os) const override;
 	/// is this equivalent to a space (which is BTW different from
diff --git a/src/insets/InsetSpace.cpp b/src/insets/InsetSpace.cpp
index 8ad6f7f5e0..8991c1166f 100644
--- a/src/insets/InsetSpace.cpp
+++ b/src/insets/InsetSpace.cpp
@@ -22,7 +22,6 @@
 #include "FuncStatus.h"
 #include "Language.h"
 #include "LaTeXFeatures.h"
-#include "Lexer.h"
 #include "MetricsInfo.h"
 #include "texstream.h"
 #include "xml.h"
@@ -37,12 +36,14 @@
 
 #include "frontends/Application.h"
 #include "frontends/FontMetrics.h"
+#include "support/Lexer.h"
 #include "frontends/Painter.h"
 
 using namespace std;
 
 namespace lyx {
 
+using support::Lexer;
 
 InsetSpace::InsetSpace(InsetSpaceParams const & params)
 	: Inset(nullptr), params_(params)
diff --git a/src/insets/InsetSpace.h b/src/insets/InsetSpace.h
index ceca1cfa06..719e09483d 100644
--- a/src/insets/InsetSpace.h
+++ b/src/insets/InsetSpace.h
@@ -79,7 +79,7 @@ struct InsetSpaceParams {
 	///
 	void write(std::ostream & os) const;
 	///
-	void read(Lexer & lex);
+	void read(support::Lexer & lex);
 	///
 	Kind kind;
 	///
@@ -123,7 +123,7 @@ public:
 	///
 	void write(std::ostream &) const override;
 	/// Will not be used when lyxf3
-	void read(Lexer & lex) override;
+	void read(support::Lexer & lex) override;
 	///
 	void latex(otexstream &, OutputParams const &) const override;
 	///
diff --git a/src/insets/InsetSpecialChar.cpp b/src/insets/InsetSpecialChar.cpp
index a1f7fec332..0e5337f51d 100644
--- a/src/insets/InsetSpecialChar.cpp
+++ b/src/insets/InsetSpecialChar.cpp
@@ -19,7 +19,6 @@
 #include "Font.h"
 #include "Language.h"
 #include "LaTeXFeatures.h"
-#include "Lexer.h"
 #include "MetricsInfo.h"
 #include "output_xhtml.h"
 #include "xml.h"
@@ -31,11 +30,14 @@
 
 #include "support/debug.h"
 #include "support/docstream.h"
+#include "support/Lexer.h"
 
 using namespace std;
 
 namespace lyx {
 
+using support::Lexer;
+
 
 InsetSpecialChar::InsetSpecialChar(Kind k)
 	: Inset(nullptr), kind_(k)
diff --git a/src/insets/InsetSpecialChar.h b/src/insets/InsetSpecialChar.h
index 5f7338b8dd..dab1bc3da1 100644
--- a/src/insets/InsetSpecialChar.h
+++ b/src/insets/InsetSpecialChar.h
@@ -71,7 +71,7 @@ public:
 	///
 	void write(std::ostream &) const override;
 	/// Will not be used when lyxf3
-	void read(Lexer & lex) override;
+	void read(support::Lexer & lex) override;
 	///
 	void latex(otexstream &, OutputParams const &) const override;
 	///
diff --git a/src/insets/InsetTabular.cpp b/src/insets/InsetTabular.cpp
index 5242775e7f..46b54486de 100644
--- a/src/insets/InsetTabular.cpp
+++ b/src/insets/InsetTabular.cpp
@@ -38,7 +38,6 @@
 #include "InsetList.h"
 #include "Language.h"
 #include "LaTeXFeatures.h"
-#include "Lexer.h"
 #include "LyX.h"
 #include "LyXRC.h"
 #include "MetricsInfo.h"
@@ -64,6 +63,7 @@
 #include "support/FileName.h"
 #include "support/gettext.h"
 #include "support/lassert.h"
+#include "support/Lexer.h"
 #include "support/lstrings.h"
 #include "support/unique_ptr.h"
 
diff --git a/src/insets/InsetTabular.h b/src/insets/InsetTabular.h
index c38fab0385..f6939c6eff 100644
--- a/src/insets/InsetTabular.h
+++ b/src/insets/InsetTabular.h
@@ -45,10 +45,10 @@ class CompletionList;
 class Cursor;
 class CursorSlice;
 class FuncStatus;
-class Lexer;
 class OutputParams;
 class XMLStream;
 
+namespace support { class Lexer; }
 
 ///
 class InsetTableCell : public InsetText
@@ -603,7 +603,7 @@ public:
 	///
 	void write(std::ostream &) const;
 	///
-	void read(Lexer &);
+	void read(support::Lexer &);
 	///
 	void latex(otexstream &, OutputParams const &) const;
 	/// serialise the table in DocBook, according to buffer parameters
@@ -1021,7 +1021,7 @@ public:
 	///
 	static std::string params2string(InsetTabular const &);
 	///
-	void read(Lexer &) override;
+	void read(support::Lexer &) override;
 	///
 	void write(std::ostream &) const override;
 	///
diff --git a/src/insets/InsetText.cpp b/src/insets/InsetText.cpp
index b8e65709a1..084e418027 100644
--- a/src/insets/InsetText.cpp
+++ b/src/insets/InsetText.cpp
@@ -39,7 +39,7 @@
 #include "Language.h"
 #include "Layout.h"
 #include "LaTeXFeatures.h"
-#include "Lexer.h"
+#include "support/Lexer.h"
 #include "lyxfind.h"
 #include "LyXRC.h"
 #include "MetricsInfo.h"
diff --git a/src/insets/InsetText.h b/src/insets/InsetText.h
index bce125bcca..423735a032 100644
--- a/src/insets/InsetText.h
+++ b/src/insets/InsetText.h
@@ -51,7 +51,7 @@ public:
 	/// empty inset to empty par
 	void clear();
 	///
-	void read(Lexer & lex) override;
+	void read(support::Lexer & lex) override;
 	///
 	void write(std::ostream & os) const override;
 	/// Let the inset compute and store its reference font from \c outer.
diff --git a/src/insets/InsetVSpace.cpp b/src/insets/InsetVSpace.cpp
index 80fba4dd1d..d3c6012b3f 100644
--- a/src/insets/InsetVSpace.cpp
+++ b/src/insets/InsetVSpace.cpp
@@ -20,7 +20,6 @@
 #include "DispatchResult.h"
 #include "FuncRequest.h"
 #include "FuncStatus.h"
-#include "Lexer.h"
 #include "MetricsInfo.h"
 #include "xml.h"
 #include "texstream.h"
@@ -29,6 +28,7 @@
 #include "support/debug.h"
 #include "support/docstream.h"
 #include "support/gettext.h"
+#include "support/Lexer.h"
 #include "support/lassert.h"
 
 #include "frontends/Application.h"
@@ -41,6 +41,8 @@ using namespace std;
 
 namespace lyx {
 
+using support::Lexer;
+
 namespace {
 
 int const ADD_TO_VSPACE_WIDTH = 5;
diff --git a/src/insets/InsetVSpace.h b/src/insets/InsetVSpace.h
index 51c2b5b885..e43dc306aa 100644
--- a/src/insets/InsetVSpace.h
+++ b/src/insets/InsetVSpace.h
@@ -58,7 +58,7 @@ private:
 	/// in fact, appear at all.
 	docstring xhtml(XMLStream &, OutputParams const &) const override;
 	///
-	void read(Lexer & lex) override;
+	void read(support::Lexer & lex) override;
 	///
 	void write(std::ostream & os) const override;
 	///
diff --git a/src/insets/InsetWrap.cpp b/src/insets/InsetWrap.cpp
index 69e5b259e5..85d7ea229a 100644
--- a/src/insets/InsetWrap.cpp
+++ b/src/insets/InsetWrap.cpp
@@ -25,7 +25,6 @@
 #include "FuncRequest.h"
 #include "FuncStatus.h"
 #include "LaTeXFeatures.h"
-#include "Lexer.h"
 #include "xml.h"
 #include "texstream.h"
 #include "TextClass.h"
@@ -33,6 +32,7 @@
 #include "support/debug.h"
 #include "support/docstream.h"
 #include "support/gettext.h"
+#include "support/Lexer.h"
 
 #include "frontends/Application.h"
 
@@ -43,6 +43,8 @@ using namespace std;
 
 namespace lyx {
 
+using support::Lexer;
+
 InsetWrap::InsetWrap(Buffer * buf, string const & type)
 	: InsetCaptionable(buf)
 {
diff --git a/src/insets/InsetWrap.h b/src/insets/InsetWrap.h
index a44821e428..01541fdabf 100644
--- a/src/insets/InsetWrap.h
+++ b/src/insets/InsetWrap.h
@@ -25,7 +25,7 @@ public:
 	///
 	void write(std::ostream &) const;
 	///
-	void read(Lexer &);
+	void read(support::Lexer &);
 
 	///
 	std::string type;
@@ -60,7 +60,7 @@ private:
 	///
 	void write(std::ostream & os) const override;
 	///
-	void read(Lexer & lex) override;
+	void read(support::Lexer & lex) override;
 	///
 	void validate(LaTeXFeatures & features) const override;
 	///
diff --git a/src/mathed/InsetMathHull.h b/src/mathed/InsetMathHull.h
index 8e527c4d52..1875417d5d 100644
--- a/src/mathed/InsetMathHull.h
+++ b/src/mathed/InsetMathHull.h
@@ -137,9 +137,9 @@ public:
 	///
 	void footer_write(TeXMathStream &) const;
 	///
-	void read(Lexer & lex) override;
+	void read(support::Lexer & lex) override;
 	///
-	bool readQuiet(Lexer & lex);
+	bool readQuiet(support::Lexer & lex);
 	///
 	int plaintext(odocstringstream &, OutputParams const &,
 	              size_t max_length = INT_MAX) const override;
diff --git a/src/mathed/InsetMathMacroTemplate.cpp b/src/mathed/InsetMathMacroTemplate.cpp
index 2a2a87eb57..9b2fd19dab 100644
--- a/src/mathed/InsetMathMacroTemplate.cpp
+++ b/src/mathed/InsetMathMacroTemplate.cpp
@@ -32,7 +32,6 @@
 #include "FuncRequest.h"
 #include "FuncStatus.h"
 #include "LaTeXFeatures.h"
-#include "Lexer.h"
 #include "MetricsInfo.h"
 #include "TocBackend.h"
 
@@ -45,6 +44,7 @@
 #include "support/debug.h"
 #include "support/gettext.h"
 #include "support/docstream.h"
+#include "support/Lexer.h"
 #include "support/lstrings.h"
 
 #include <set>
@@ -55,6 +55,7 @@ using namespace std;
 namespace lyx {
 
 using support::bformat;
+using support::Lexer;
 
 //////////////////////////////////////////////////////////////////////
 
diff --git a/src/mathed/InsetMathMacroTemplate.h b/src/mathed/InsetMathMacroTemplate.h
index 1fa6d00989..785385a7db 100644
--- a/src/mathed/InsetMathMacroTemplate.h
+++ b/src/mathed/InsetMathMacroTemplate.h
@@ -45,7 +45,7 @@ public:
 	///
 	bool notifyCursorLeaves(Cursor const & old, Cursor & cur) override;
 	///
-	void read(Lexer & lex) override;
+	void read(support::Lexer & lex) override;
 	///
 	void write(std::ostream & os) const override;
 	///
diff --git a/src/mathed/MathParser.cpp b/src/mathed/MathParser.cpp
index 79e0ec003d..eb4339c8ea 100644
--- a/src/mathed/MathParser.cpp
+++ b/src/mathed/MathParser.cpp
@@ -72,11 +72,11 @@ following hack as starting point to write some macros:
 #include "Buffer.h"
 #include "BufferParams.h"
 #include "Encoding.h"
-#include "Lexer.h"
 
 #include "support/convert.h"
 #include "support/debug.h"
 #include "support/docstream.h"
+#include "support/Lexer.h"
 
 #include <sstream>
 
@@ -86,6 +86,8 @@ using namespace std;
 
 namespace lyx {
 
+using support::Lexer;
+
 namespace {
 
 InsetMath::mode_type asMode(InsetMath::mode_type oldmode, docstring const & str)
diff --git a/src/mathed/MathParser.h b/src/mathed/MathParser.h
index d69c78a11a..734a92f2f9 100644
--- a/src/mathed/MathParser.h
+++ b/src/mathed/MathParser.h
@@ -24,8 +24,8 @@ class Buffer;
 class MathAtom;
 class MathData;
 class InsetMathGrid;
-class Lexer;
 
+namespace support { class Lexer; }
 
 ///
 class latexkeys {
@@ -75,7 +75,7 @@ bool mathed_parse_normal(Buffer * buf, MathAtom &, docstring const &,
 		Parse::flags f = Parse::NORMAL);
 
 /// parse formula from the LyX lexxer
-bool mathed_parse_normal(Buffer * buf, MathAtom &, Lexer &,
+bool mathed_parse_normal(Buffer * buf, MathAtom &, support::Lexer &,
 		Parse::flags f = Parse::NORMAL);
 
 /// parse formula from a string into a grid
diff --git a/src/Lexer.cpp b/src/support/Lexer.cpp
similarity index 99%
rename from src/Lexer.cpp
rename to src/support/Lexer.cpp
index b964eab2c4..fd8840d1a3 100644
--- a/src/Lexer.cpp
+++ b/src/support/Lexer.cpp
@@ -13,7 +13,7 @@
 
 #include <config.h>
 
-#include "Lexer.h"
+#include "support/Lexer.h"
 
 #include "support/convert.h"
 #include "support/debug.h"
@@ -32,10 +32,11 @@
 #include <vector>
 
 using namespace std;
-using namespace lyx::support;
 
 namespace lyx {
 
+namespace support {
+
 //////////////////////////////////////////////////////////////////////
 //
 // Lexer::Pimpl
@@ -923,5 +924,6 @@ void Lexer::setContext(std::string const & functionName)
 	pimpl_->context = functionName;
 }
 
+} // namespace support
 
 } // namespace lyx
diff --git a/src/Lexer.h b/src/support/Lexer.h
similarity index 98%
rename from src/Lexer.h
rename to src/support/Lexer.h
index 02ec7470e1..96ac205aba 100644
--- a/src/Lexer.h
+++ b/src/support/Lexer.h
@@ -22,7 +22,9 @@
 
 namespace lyx {
 
-namespace support { class FileName; }
+namespace support {
+
+class FileName;
 
 /** A helper structure to describe a keyword for the Lexer.
 	Usually used bundled in C style arrays and passed to the
@@ -37,7 +39,7 @@ struct LexerKeyword
 };
 
 
-/** Generalized simple lexical analizer.
+/** Generalized simple lexical analyzer.
 	Use the method isOK() to check if there is still data available
 	for lexing. Use one of the the operators void* or ! to test if
 	the last reading operation was successful.
@@ -255,6 +257,7 @@ public:
 #define PushPopHelper(x, y, z) unnamed_PushPopHelper;
 // Tip gotten from Bobby Schmidt's column in C/C++ Users Journal
 
+} // namespace support
 
 } // namespace lyx
 
diff --git a/src/support/Makefile.am b/src/support/Makefile.am
index 2c2fce5f46..5c181d6852 100644
--- a/src/support/Makefile.am
+++ b/src/support/Makefile.am
@@ -77,6 +77,8 @@ liblyxsupport_a_SOURCES = \
 	Length.cpp \
 	Length.h \
 	lengthcommon.cpp \
+	Lexer.cpp \
+	Lexer.h \
 	limited_stack.h \
 	lstrings.cpp \
 	lstrings.h \
diff --git a/src/tex2lyx/Preamble.cpp b/src/tex2lyx/Preamble.cpp
index 3226b0f0a5..33885556b5 100644
--- a/src/tex2lyx/Preamble.cpp
+++ b/src/tex2lyx/Preamble.cpp
@@ -19,13 +19,13 @@
 #include "Encoding.h"
 #include "LaTeXPackages.h"
 #include "LayoutFile.h"
-#include "Lexer.h"
 #include "TextClass.h"
 #include "version.h"
 
 #include "support/convert.h"
 #include "support/FileName.h"
 #include "support/filetools.h"
+#include "support/Lexer.h"
 #include "support/lstrings.h"
 
 #include <algorithm>