Clean up C extension

This commit fixes a few warnings in the C extension. It also fixes a bug
by calling `global_parse` instead of `_parse`.

Fixes #124

.gitignore

@@ -32,3 +32,6 @@ mkmf.log
 Makefile
 ext/mathematical/build
 ext/mathematical/lasem/build
+# clangd files
+*compile_commands.json
+*.cache

ext/mathematical/lasem_overrides.c

@@ -17,7 +17,7 @@ lsm_itex_free_mathml_buffer	(char *mathml)
 }
 
 char *
-lsm_itex_to_mathml (const char *itex, gssize size) { }
+lsm_itex_to_mathml (const char *itex, gssize size) { return NULL; }
 
 
 char *
@@ -27,7 +27,7 @@ lsm_mtex_to_mathml (const char *mtex, gssize size, int delimiter, int render_typ
   char *mathml;
   int status = 0;
 
-  if (mtex == NULL) {
+  if (!mtex) {
     return NULL;
   }
 
@@ -42,7 +42,7 @@ lsm_mtex_to_mathml (const char *mtex, gssize size, int delimiter, int render_typ
 
   switch (render_type) {
   case PARSE:
-    mathml = mtex2MML_parse(mtex, usize, delimiter);
+    mathml = mtex2MML_global_parse(mtex, usize, delimiter, 1);
     if (mathml == NULL) {
       status = 1;
     }
@@ -60,7 +60,7 @@ lsm_mtex_to_mathml (const char *mtex, gssize size, int delimiter, int render_typ
     mathml = mtex2MML_output();
     break;
   default:
-    mathml = mtex2MML_parse(mtex, usize, delimiter);
+    mathml = mtex2MML_global_parse(mtex, usize, delimiter, 1);
     if (mathml == NULL) {
       status = 1;
     }
@@ -82,9 +82,5 @@ lsm_mtex_to_mathml (const char *mtex, gssize size, int delimiter, int render_typ
 void
 lsm_mtex_free_mathml_buffer (char *mathml)
 {
-  if (mathml == NULL) {
-    return;
-  }
-
   mtex2MML_free_string (mathml);
 }

ext/mathematical/mathematical.c

@@ -145,14 +145,12 @@ VALUE process(VALUE self, unsigned long maxsize, const char *latex_code, unsigne
   lsm_dom_view_render (view, cairo, 0, 0);
 
   switch (format) {
-  case FORMAT_PNG: {
+  case FORMAT_PNG:
     cairo_surface_write_to_png_stream (cairo_get_target (cairo), cairoPngSurfaceCallback, self);
     break;
-  }
-  default: {
+  default:
     break;
   }
-  }
 
   cairo_destroy (cairo);
   cairo_surface_destroy (surface);