Add a tooltips option to HtmlFormatter. (#1822)

* Add a tooltips option to HtmlFormmater.

* Rename option tooltips to debug_token_types.

* Use explicit if block.

* Fix check.

* Document how to use the new debug_token_types option for the HTML formatter.

* Remove output redirection from example call.

1 files changed, 17 insertions, 2 deletions

diff --git a/pygments/formatters/html.py b/pygments/formatters/html.py
index f9588f78..ba2df3fa 100644
--- a/pygments/formatters/html.py
+++ b/pygments/formatters/html.py
@@ -349,6 +349,12 @@ class HtmlFormatter(Formatter):
 
         .. versionadded:: 2.4
 
+    `debug_token_types`
+        Add ``title`` attributes to all token ``<span>`` tags that show the
+        name of the token.
+
+        .. versionadded:: 2.10
+
 
     **Subclassing the HTML formatter**
 
@@ -419,6 +425,7 @@ class HtmlFormatter(Formatter):
         self.filename = self._decodeifneeded(options.get('filename', ''))
         self.wrapcode = get_bool_opt(options, 'wrapcode', False)
         self.span_element_openers = {}
+        self.debug_token_types = get_bool_opt(options, 'debug_token_types', False)
 
         if self.tagsfile:
             if not ctags:
@@ -836,12 +843,20 @@ class HtmlFormatter(Formatter):
             try:
                 cspan = self.span_element_openers[ttype]
             except KeyError:
+                title = ' title="%s"' % '.'.join(ttype) if self.debug_token_types else ''
                 if nocls:
                     css_style = self._get_css_inline_styles(ttype)
-                    cspan = css_style and '<span style="%s">' % self.class2style[css_style][0] or ''
+                    if css_style:
+                        css_style = self.class2style[css_style][0]
+                        cspan = '<span style="%s"%s>' % (css_style, title)
+                    else:
+                        cspan = ''
                 else:
                     css_class = self._get_css_classes(ttype)
-                    cspan = css_class and '<span class="%s">' % css_class or ''
+                    if css_class:
+                        cspan = '<span class="%s"%s>' % (css_class, title)
+                    else:
+                        cspan = ''
                 self.span_element_openers[ttype] = cspan
 
             parts = self._translate_parts(value)