Merge branch 'katex-math' into 'master'

Render math in Asciidoc and Markdown with KaTeX using code blocks

Closes #13690 and #13180

See merge request !8003

1 files changed, 37 insertions, 0 deletions

diff --git a/doc/user/markdown.md b/doc/user/markdown.md
index 4d24eb21976..f6484688721 100644
--- a/doc/user/markdown.md
+++ b/doc/user/markdown.md
@@ -319,6 +319,40 @@ Here's a sample video:
 
 ![Sample Video](img/markdown_video.mp4)
 
+### Math
+
+> If this is not rendered correctly, see
+https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/user/markdown.md#math
+
+It is possible to have math written with the LaTeX syntax rendered using [KaTeX][katex].
+
+Math written inside ```$``$``` will be rendered inline with the text.
+
+Math written inside triple back quotes, with the language declared as `math`, will be rendered on a separate line.
+
+Example:
+
+    This math is inline $`a^2+b^2=c^2`$.
+
+    This is on a separate line
+    ```math
+    a^2+b^2=c^2
+    ```
+
+Becomes:
+
+This math is inline $`a^2+b^2=c^2`$.
+
+This is on a separate line
+```math
+a^2+b^2=c^2
+```
+
+_Be advised that KaTeX only supports a [subset][katex-subset] of LaTeX._
+
+>**Note:**
+This also works for the asciidoctor `:stem: latexmath`. For details see the [asciidoctor user manual][asciidoctor-manual].
+
 ## Standard Markdown
 
 ### Headers
@@ -764,3 +798,6 @@ A link starting with a `/` is relative to the wiki root.
 [markdown.md]: https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/user/markdown.md
 [rouge]: http://rouge.jneen.net/ "Rouge website"
 [redcarpet]: https://github.com/vmg/redcarpet "Redcarpet website"
+[katex]: https://github.com/Khan/KaTeX "KaTeX website"
+[katex-subset]: https://github.com/Khan/KaTeX/wiki/Function-Support-in-KaTeX "Macros supported by KaTeX"
+[asciidoctor-manual]: http://asciidoctor.org/docs/user-manual/#activating-stem-support "Asciidoctor user manual"
\ No newline at end of file