Help: Override pygments CMakeLexer to support <..> and [..]

* The code snippets in the docs consist of CMake code mixed
  with syntax definition punctuation like < > [ ] ... Therefore
  a pure CMake lexer is inadequate. Here it is replaced by a
  CMake syntax definition parser.
* Fixed syntax definition snippets in FindPkgConfig.cmake to
  make best use of syntax highlighting. This source file is the
  hardest to support because it contains comparison operators
  <= = >=, which need special attention to avoid confusion
  with the placeholder indicators <...>.
* Fixed syntax in execute_process.rst (there were unbalanced
  brackets).
* Disabled syntax highlighting for long string examples in
  cmake-language.7.rst.
* No highlighting of removed syntax in CMP0049
* To inspect the outcome of this patch, see e.g. the pages
  * manual/cmake-buildsystem.7.html
  * module/ExternalProject.html
  * module/FindPkgConfig.html
  which are particularly rich in complex code snippets.

1 files changed, 29 insertions, 0 deletions

diff --git a/Utilities/Sphinx/colors.py b/Utilities/Sphinx/colors.py
new file mode 100644
index 0000000000..f98a4831fd
--- /dev/null
+++ b/Utilities/Sphinx/colors.py
@@ -0,0 +1,29 @@
+# -*- coding: utf-8 -*-
+
+from pygments.style import Style
+from pygments.token import Name, Comment, String, Number, Operator, Whitespace
+
+class CMakeTemplateStyle(Style):
+    """
+        for more token names, see pygments/styles.default
+    """
+
+    background_color = "#f8f8f8"
+    default_style = ""
+
+    styles = {
+        Whitespace:                "#bbbbbb",
+        Comment:                   "italic #408080",
+        Operator:                  "bold #000000",
+        String:                    "#217A21",
+        Number:                    "#105030",
+        Name.Builtin:              "#400080",          # anything lowercase
+        Name.Function:             "bold #1010A0",     # function
+        Name.Variable:             "#1080B0",          # <..>
+        Name.Tag:                  "#19177C",          # ${..}
+        Name.Constant:             "#6020E0",          # uppercase only
+        Name.Entity:               "italic #70A020",   # @..@
+        Name.Attribute:            "#906060",          # paths, URLs
+        Name.Label:                "#A0A000",          # anything left over
+        Name.Exception:            "bold #FF0000",     # for debugging only
+    }