1 files changed, 76 insertions, 0 deletions
diff --git a/compiler/rustc_errors/src/markdown/mod.rs b/compiler/rustc_errors/src/markdown/mod.rs
new file mode 100644
index 000000000..53b766dfc
--- /dev/null
+++ b/compiler/rustc_errors/src/markdown/mod.rs
@@ -0,0 +1,76 @@
+//! A simple markdown parser that can write formatted text to the terminal
+//!
+//! Entrypoint is `MdStream::parse_str(...)`
+use std::io;
+
+use termcolor::{Buffer, BufferWriter, ColorChoice};
+mod parse;
+mod term;
+
+/// An AST representation of a Markdown document
+#[derive(Clone, Debug, Default, PartialEq)]
+pub struct MdStream<'a>(Vec<MdTree<'a>>);
+
+impl<'a> MdStream<'a> {
+    /// Parse a markdown string to a tokenstream
+    #[must_use]
+    pub fn parse_str(s: &str) -> MdStream<'_> {
+        parse::entrypoint(s)
+    }
+
+    /// Write formatted output to a termcolor buffer
+    pub fn write_termcolor_buf(&self, buf: &mut Buffer) -> io::Result<()> {
+        term::entrypoint(self, buf)
+    }
+}
+
+/// Create a termcolor buffer with the `Always` color choice
+pub fn create_stdout_bufwtr() -> BufferWriter {
+    BufferWriter::stdout(ColorChoice::Always)
+}
+
+/// A single tokentree within a Markdown document
+#[derive(Clone, Debug, PartialEq)]
+pub enum MdTree<'a> {
+    /// Leaf types
+    Comment(&'a str),
+    CodeBlock {
+        txt: &'a str,
+        lang: Option<&'a str>,
+    },
+    CodeInline(&'a str),
+    Strong(&'a str),
+    Emphasis(&'a str),
+    Strikethrough(&'a str),
+    PlainText(&'a str),
+    /// [Foo](www.foo.com) or simple anchor <www.foo.com>
+    Link {
+        disp: &'a str,
+        link: &'a str,
+    },
+    /// `[Foo link][ref]`
+    RefLink {
+        disp: &'a str,
+        id: Option<&'a str>,
+    },
+    /// [ref]: www.foo.com
+    LinkDef {
+        id: &'a str,
+        link: &'a str,
+    },
+    /// Break bewtween two paragraphs (double `\n`), not directly parsed but
+    /// added later
+    ParagraphBreak,
+    /// Break bewtween two lines (single `\n`)
+    LineBreak,
+    HorizontalRule,
+    Heading(u8, MdStream<'a>),
+    OrderedListItem(u16, MdStream<'a>),
+    UnorderedListItem(MdStream<'a>),
+}
+
+impl<'a> From<Vec<MdTree<'a>>> for MdStream<'a> {
+    fn from(value: Vec<MdTree<'a>>) -> Self {
+        Self(value)
+    }
+}