Allow context menus in mathed

It is now possible to get a context menu for math insets.
InsetMathSpace was already providing a specific context menu,
but it was never triggered because the math hull inset is not
descendable. It is still so, but now when a context menu is
requested all the insets inside the math hull are examined.
If the inset under the cursor provides a context menu, it
is shown instead of the general math one.

Fixes #12100.

src/BufferView.cpp

@@ -50,7 +50,7 @@
 #include "insets/InsetRef.h"
 #include "insets/InsetText.h"
 
-#include "mathed/InsetMath.h"
+#include "mathed/InsetMathNest.h"
 #include "mathed/MathData.h"
 #include "mathed/MathRow.h"
 
@@ -669,13 +669,53 @@ string BufferView::contextMenu(int x, int y) const
 
 	// Get inset under mouse, if there is one.
 	Inset const * covering_inset = getCoveringInset(buffer_.text(), x, y);
-	if (covering_inset)
+	if (covering_inset) {
+		if (covering_inset->asInsetMath()) {
+			CoordCache::Insets const & inset_cache =
+				coordCache().getInsets();
+			Inset const * inner_inset = mathContextMenu(
+				covering_inset->asInsetMath()->asNestInset(),
+				inset_cache, x, y);
+			if (inner_inset)
+				return inner_inset->contextMenu(*this, x, y);
+		}
 		return covering_inset->contextMenu(*this, x, y);
+	}
 
 	return buffer_.inset().contextMenu(*this, x, y);
 }
 
 
+Inset const * BufferView::mathContextMenu(InsetMathNest const * inset,
+		CoordCache::Insets const & inset_cache, int x, int y) const
+{
+	for (size_t i = 0; i < inset->nargs(); ++i) {
+		MathData const & ar = inset->cell(i);
+		for (size_t j = 0; j < ar.size(); ++j) {
+			string const name = lyxerr.debugging(Debug::MATHED)
+				? insetName(ar[j].nucleus()->lyxCode())
+				: string();
+			LYXERR(Debug::MATHED, "Examining inset: " << name);
+			if (!ar[j].nucleus()->contextMenuName().empty()) {
+				if (inset_cache.covers(ar[j].nucleus(), x, y)) {
+					LYXERR(Debug::MATHED, "Hit inset: "
+					       << name);
+					return ar[j].nucleus();
+				}
+			}
+			InsetMathNest const * imn =
+				ar[j].nucleus()->asNestInset();
+			if (imn) {
+				Inset const * inner =
+					mathContextMenu(imn, inset_cache, x, y);
+				if (inner)
+					return inner;
+			}
+		}
+	}
+	return nullptr;
+}
+
 
 void BufferView::scrollDocView(int const pixels, bool update)
 {

src/BufferView.h

@@ -15,6 +15,7 @@
 #ifndef BUFFER_VIEW_H
 #define BUFFER_VIEW_H
 
+#include "CoordCache.h"
 #include "DocumentClassPtr.h"
 #include "TexRow.h"
 #include "update_flags.h"
@@ -32,7 +33,6 @@ namespace frontend { class GuiBufferViewDelegate; }
 
 class Buffer;
 class Change;
-class CoordCache;
 class Cursor;
 class CursorSlice;
 class Dimension;
@@ -42,6 +42,7 @@ class FuncRequest;
 class FuncStatus;
 class Intl;
 class Inset;
+class InsetMathNest;
 class Length;
 class MathData;
 class MathRow;
@@ -160,6 +161,9 @@ public:
 	docstring toolTip(int x, int y) const;
 	/// \return the context menu for the given position.
 	std::string contextMenu(int x, int y) const;
+	/// \return the math inset with a context menu for the given position
+	Inset const * mathContextMenu(InsetMathNest const * inset,
+		CoordCache::Insets const & inset_cache, int x, int y) const;
 
 	/// Save the current position as bookmark.
 	/// if idx == 0, save to temp_bookmark

src/mathed/InsetMathRef.h

@@ -33,6 +33,12 @@ public:
 	///
 	void infoize(odocstream & os) const override;
 	///
+	bool hasSettings() const override { return true; }
+	///
+	bool clickable(BufferView const &, int, int) const override { return true; }
+	///
+	std::string contextMenuName() const override { return "context-ref"; }
+	///
 	mode_type currentMode() const override { return TEXT_MODE; }
 	///
 	bool lockedMode() const override { return true; }

src/mathed/InsetMathSpace.h

@@ -62,6 +62,8 @@ public:
 	///
 	bool hasSettings() const override { return true; }
 	///
+	bool clickable(BufferView const &, int, int) const override { return true; }
+	///
 	std::string contextMenuName() const override;
 	///
 	bool getStatus(Cursor &, FuncRequest const &, FuncStatus &) const override;