Add support for parsing MDX ESM, expressions

This commit adds support for hooks that lets a user integrate another
parser with `micromark-rs`, to parse ESM and expressions according to
a particular grammar (such as a programming language, typically
JavaScript).

For an example integrating with SWC, see `tests/test_utils/mod.rs`.

The integration occurs with two functions passed in `options`:
`mdx_expression_parse` and `mdx_esm_parse`.
The can signal back to micromark when they are successful,
whether there is an error at the end (in which case micromark will
try to parse more), or whether there is a syntax error (in which case
micromark will crash).

1 files changed, 12 insertions, 2 deletions

diff --git a/tests/math_text.rs b/tests/math_text.rs
index dced393..7b53268 100644
--- a/tests/math_text.rs
+++ b/tests/math_text.rs
@@ -30,7 +30,12 @@ fn math_text() -> Result<(), String> {
             "$foo$ $$bar$$",
             &Options {
                 math_text_single_dollar: false,
-                ..math.clone()
+                constructs: Constructs {
+                    math_text: true,
+                    math_flow: true,
+                    ..Constructs::default()
+                },
+                ..Options::default()
             }
         )?,
         "<p>$foo$ <code class=\"language-math math-inline\">bar</code></p>",
@@ -133,7 +138,12 @@ fn math_text() -> Result<(), String> {
             &Options {
                 allow_dangerous_html: true,
                 allow_dangerous_protocol: true,
-                ..math.clone()
+                constructs: Constructs {
+                    math_text: true,
+                    math_flow: true,
+                    ..Constructs::default()
+                },
+                ..Options::default()
             }
         )?,
         "<p><a href=\"$\">$</p>",