From 66f7c2930ad5ba39f4b874a0d3b00fd55edfe4c4 Mon Sep 17 00:00:00 2001
From: Juergen Spitzmueller <spitz@lyx.org>
Date: Mon, 12 Dec 2016 15:55:28 +0100
Subject: [PATCH] texstream: implement way to terminate a command depending on
 the context

i.e.,
* space if non terminating char follows
* {} if space follows
* nothing if \, { or } follow
---
 src/texstream.cpp | 55 ++++++++++++++++++++++++++++++++++++++++++++---
 src/texstream.h   | 17 ++++++++++++++-
 2 files changed, 68 insertions(+), 4 deletions(-)

diff --git a/src/texstream.cpp b/src/texstream.cpp
index 5b0e927591..10033a9255 100644
--- a/src/texstream.cpp
+++ b/src/texstream.cpp
@@ -59,11 +59,23 @@ void otexrowstream::put(char_type const & c)
 
 void otexstream::put(char_type const & c)
 {
+	bool isprotected = false;
 	if (protectspace_) {
-		if (!canbreakline_ && c == ' ')
+		if (!canbreakline_ && c == ' ') {
 			os() << "{}";
+			isprotected = true;
+		}
 		protectspace_ = false;
 	}
+	if (terminate_command_) {
+		if ((c == ' ' || c == '\0') && !isprotected)
+			// A space follows. Terminate with brackets.
+			os() << "{}";
+		else if (c != '\\' && c != '{' && c != '}')
+			// Non-terminating character follows. Terminate with space.
+			os() << " ";
+		terminate_command_ = false;
+	}
 	otexrowstream::put(c);
 	lastChar(c);
 }
@@ -89,6 +101,7 @@ TexString otexstringstream::release()
 
 BreakLine breakln;
 SafeBreakLine safebreakln;
+TerminateCommand termcmd;
 
 
 otexstream & operator<<(otexstream & ots, BreakLine)
@@ -98,6 +111,7 @@ otexstream & operator<<(otexstream & ots, BreakLine)
 		ots.lastChar('\n');
 	}
 	ots.protectSpace(false);
+	ots.terminateCommand(false);
 	return ots;
 }
 
@@ -110,6 +124,14 @@ otexstream & operator<<(otexstream & ots, SafeBreakLine)
 		ots.lastChar('\n');
 	}
 	ots.protectSpace(false);
+	ots.terminateCommand(false);
+	return ots;
+}
+
+
+otexstream & operator<<(otexstream & ots, TerminateCommand)
+{
+	ots.terminateCommand(true);
 	return ots;
 }
 
@@ -152,11 +174,24 @@ otexstream & operator<<(otexstream & ots, TexString ts)
 		return ots;
 
 	otexrowstream & otrs = ots;
+	bool isprotected = false;
+	char const c = ts.str[0];
 	if (ots.protectSpace()) {
-		if (!ots.canBreakLine() && ts.str[0] == ' ')
+		if (!ots.canBreakLine() && c == ' ') {
 			otrs << "{}";
+			isprotected = true;
+		}
 		ots.protectSpace(false);
 	}
+	if (ots.terminateCommand()) {
+		if ((c == ' ' || c == '\0') && !isprotected)
+			// A space follows. Terminate with brackets.
+			otrs << "{}";
+		else if (c != '\\' && c != '{' && c != '}')
+			// Non-terminating character follows. Terminate with space.
+			otrs << " ";
+		ots.terminateCommand(false);
+	}
 
 	if (len > 1)
 		ots.canBreakLine(ts.str[len - 2] != '\n');
@@ -183,11 +218,24 @@ otexstream & operator<<(otexstream & ots, docstring const & s)
 	if (len == 0)
 		return ots;
 	otexrowstream & otrs = ots;
+	bool isprotected = false;
+	char const c = s[0];
 	if (ots.protectSpace()) {
-		if (!ots.canBreakLine() && s[0] == ' ')
+		if (!ots.canBreakLine() && c == ' ') {
 			otrs << "{}";
+			isprotected = true;
+		}
 		ots.protectSpace(false);
 	}
+	if (ots.terminateCommand()) {
+		if ((c == ' ' || c == '\0') && !isprotected)
+			// A space follows. Terminate with brackets.
+			otrs << "{}";
+		else if (c != '\\' && c != '{' && c != '}')
+			// Non-terminating character follows. Terminate with space.
+			otrs << " ";
+		ots.terminateCommand(false);
+	}
 
 	if (contains(s, 0xF0000)) {
 		// Some encoding changes for the underlying stream are embedded
@@ -290,6 +338,7 @@ otexstream & operator<<(otexstream & ots, Type value)
 	ots.os() << value;
 	ots.lastChar(0);
 	ots.protectSpace(false);
+	ots.terminateCommand(false);
 	return ots;
 }
 
diff --git a/src/texstream.h b/src/texstream.h
index e5450ce741..bf4eb38bba 100644
--- a/src/texstream.h
+++ b/src/texstream.h
@@ -81,7 +81,8 @@ public:
 	///
 	explicit otexstream(odocstream & os)
 		: otexrowstream(os), canbreakline_(false),
-		  protectspace_(false), parbreak_(true), lastchar_(0) {}
+		  protectspace_(false), terminate_command_(false),
+		  parbreak_(true), lastchar_(0) {}
 	///
 	void put(char_type const & c);
 	///
@@ -95,6 +96,10 @@ public:
 	///
 	bool protectSpace() const { return protectspace_; }
 	///
+	void terminateCommand(bool terminate) { terminate_command_ = terminate; }
+	///
+	bool terminateCommand() const { return terminate_command_; }
+	///
 	void lastChar(char_type const & c)
 	{
 		parbreak_ = (!canbreakline_ && c == '\n');
@@ -111,6 +116,8 @@ private:
 	///
 	bool protectspace_;
 	///
+	bool terminate_command_;
+	///
 	bool parbreak_;
 	///
 	char_type lastchar_;
@@ -144,14 +151,22 @@ struct SafeBreakLine {
 	char n;
 };
 
+/// Helper structs for terminating a command
+struct TerminateCommand {
+	char n;
+};
+
 extern BreakLine breakln;
 extern SafeBreakLine safebreakln;
+extern TerminateCommand termcmd;
 
 ///
 otexstream & operator<<(otexstream &, BreakLine);
 ///
 otexstream & operator<<(otexstream &, SafeBreakLine);
 ///
+otexstream & operator<<(otexstream &, TerminateCommand);
+///
 otexstream & operator<<(otexstream &, odocstream_manip);
 ///
 otexstream & operator<<(otexstream &, TexString);