Add simple TeX parser based on flex/bison. * libinterp/corefcn/oct-tex-lexer.ll, libinterp/corefcn/oct-tex-pareser.yy: New files. * libinterp/Makefile.am (BUILT_SOURCES): Add oct-tex-lexer.cc and oct-tex-parser.cc. * libinterp/corefcn/modules.mk (corefcn/oct-tex-lexer.cc, corefcn/oct-tex-parser.h): New rules. * libinterp/corefcn/txt-eng-ft.h (ft_render::text_to_pixels, ft_render::get_extent): Add interpreter argument. * libinterp/corefcn/txt-eng-ft.cc (ft_render::text_to_pixels, ft_render::get_extent): Likewise. Use text_parser::parse(). * libinterp/corefcn/gl-render.cc (opengl_renderer::text_to_pixels): Use new interpreter argument. * libinterp/corefcn/graphics.cc (axes::properties::get_ticklabel_extents): Likewise. (uicontrol::properties::update_text_extent): Use text_parser::parse. * libinterp/corefcn/txt-eng.h (memory, string, caseless-str.h, dMatrix.h): New includes. (class text_element_subscript): Renamed from text_subscript_element. (class text_element_supserscript): Renamed from text_superscript_element. (class text_element_symbol, class text_element_fontstyle, class text_element_fontname, class text_element_fontsize, class text_element_color): New classes. (text_element_list::text_element_list(text_element*)): New constructor. (text_element_subscript::text_element_subscript(text_element*), text_element_subscript::text_element::subscript(char)): New constructors. (text_element_subscript::elem): New member. (text_element_subscript::get_element): New method. Returns it. (text_element_subscript::~text_element_subscript): New destructor. Delete it. (text_element_subscript::text_element_subscript()): Make default constructor private. (text_element_superscript::text_element_superscript(text_element*), text_element_superscript::text_element::superscript(char)): New constructors. (text_element_superscript::elem): New member. (text_element_superscript::get_element): New method. Returns it. (text_element_superscript::~text_element_superscript): New destructor. Delete it. (text_element_superscript::text_element_superscript()): Make default constructor private. (text_processor::visit(text_element_symbol), text_processor::visit(text_element_fontstyle), text_processor::visit(text_element_fontname), text_processor::visit(text_element_fontsize), text_processor::visit(text_element_color)): New methods. (text_parser::parse): New static method. (class text_parser_tex): New class.

--- a/libinterp/corefcn/txt-eng-ft.cc
+++ b/libinterp/corefcn/txt-eng-ft.cc
@@ -594,9 +594,10 @@
 }
 
 Matrix
-ft_render::get_extent (const std::string& txt, double rotation)
+ft_render::get_extent (const std::string& txt, double rotation,
+                       const caseless_str& interpreter)
 {
-  text_element *elt = text_parser_none ().parse (txt);
+  text_element *elt = text_parser::parse (txt, interpreter);
   Matrix extent = get_extent (elt, rotation);
   delete elt;
 
@@ -621,14 +622,15 @@
 void
 ft_render::text_to_pixels (const std::string& txt,
                            uint8NDArray& pixels_, Matrix& box,
-                           int halign, int valign, double rotation)
+                           int halign, int valign, double rotation,
+                           const caseless_str& interpreter)
 {
   // FIXME: clip "rotation" between 0 and 360
   int rot_mode = rotation_to_mode (rotation);
 
   multiline_halign = halign;
 
-  text_element *elt = text_parser_none ().parse (txt);
+  text_element *elt = text_parser::parse (txt, interpreter);
   pixels_ = render (elt, box, rot_mode);
   delete elt;