grob: Render expressions in expression mode

This ensures that we get the right multiplication operators.

Fixes: #1148

Signed-off-by: Christophe de Dinechin <christophe@dinechin.org>

src/expression.cc

@@ -2083,6 +2083,7 @@ GRAPH_BODY(expression)
     size_t       depth = rt.depth();
     bool         ok    = true;
     bool         funcall = o->type() == ID_funcall;
+    save<bool>   sexpr(g.expression, true);
 
     // First push all things so that we have the outermost operators first
     for (object_p obj : *expr)

src/grob.h

@@ -253,14 +253,16 @@ struct grapher
             font_id       f     = settings::EDITOR,
             grob::pattern fg    = grob::pattern::black,
             grob::pattern bg    = grob::pattern::white,
-            bool          stack = false)
+            bool          stack = false,
+            bool          expr  = false)
         : maxw(w),
           maxh(h),
           voffset(0),
           font(f),
           foreground(fg),
           background(bg),
-          stack(stack)
+          stack(stack),
+          expression(expr)
     {}
     grapher(const grapher &other) = default;
 
@@ -287,6 +289,7 @@ struct grapher
     grob::pattern foreground;
     grob::pattern background;
     bool          stack;
+    bool          expression;
 };
 
 #endif // GROB_H

src/object.cc

@@ -997,7 +997,7 @@ GRAPH_BODY(object)
 //  The default for rendering is to render the text using default font
 // ----------------------------------------------------------------------------
 {
-    renderer r(nullptr, ~0U, g.stack, true);
+    renderer r(nullptr, ~0U, g.stack, true, g.expression);
     using pixsize  = blitter::size;
     size_t  sz     = o->render(r);
     gcutf8  txt    = r.text();

src/renderer.h

@@ -42,10 +42,10 @@ struct renderer
 // ----------------------------------------------------------------------------
 {
     renderer(char *buf = nullptr, size_t len = ~0U,
-             bool stk = false, bool ml = false)
+             bool stk = false, bool ml = false, bool expr = false)
         : target(buf), length(len), written(0), saving(), tabs(0), column(0),
           edit(!stk && buf == nullptr),
-          expr(false), stk(stk), mlstk(ml), txt(false),
+          expr(expr), stk(stk), mlstk(ml), txt(false),
           needSpace(false), gotSpace(false),
           needCR(false), gotCR(false) {}
     renderer(bool equation, bool edit = false, bool stk = false, bool ml = false)