oxc-markdown-parser 0.0.3

//! Parser configuration.
//!
//! MD and MDX are "the same syntax with different meanings":
//! the syntactic difference reduces to which constructs are enabled,
//! so both dialects share one parser, one AST, and one API.
//! Downstream code never branches on a dialect enum, only on which nodes actually appear.

/// Which syntax constructs the parser recognizes.
///
/// CommonMark's core (paragraphs, headings, thematic breaks, blockquotes,
/// lists, fenced code, emphasis, links, hard breaks) is always on.
/// Everything listed here is a construct that some dialect turns off or bolts on.
///
/// The default set mirrors Prettier's parser composition:
/// GFM + math + wiki-link + liquid,
/// plus container directives (`:::`), which Prettier lacks and consequently corrupts.
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub struct Constructs {
    /// `<https://example.com>` / `<user@example.com>`. Syntax error in MDX.
    pub autolink: bool,
    /// 4-space indented code blocks.
    /// In MDX the indent is an ordinary paragraph (continuation) instead.
    pub code_indented: bool,
    /// HTML blocks (CommonMark types 1–7).
    /// In MDX `<` at flow start is JSX.
    pub html_flow: bool,
    /// Inline HTML tags/comments.
    /// In MDX `<` in text is JSX.
    pub html_text: bool,

    /// GFM bare-URL links (`www.example.com`).
    /// Printed verbatim.
    pub gfm_autolink_literal: bool,
    /// GFM footnotes (`[^label]`).
    pub gfm_footnote: bool,
    /// GFM strikethrough (`~~x~~`).
    pub gfm_strikethrough: bool,
    /// Whether a single `~` also opens strikethrough.
    /// GitHub and Prettier (`singleTilde: false`) require `~~`;
    /// keep this off to leave subscript conventions like `H~2~O` alone.
    pub gfm_strikethrough_single_tilde: bool,
    /// GFM tables.
    pub gfm_table: bool,
    /// GFM task list items (`- [x]`).
    pub gfm_task_list_item: bool,

    /// `$$ … $$` display math.
    pub math_flow: bool,
    /// `$$ … $$` inline math, printed verbatim.
    pub math_text: bool,
    /// Whether a single `$` also opens inline math.
    /// Prettier (`singleDollarTextMath: false`) requires `$$`;
    /// keep this off to leave prose like `$FOO` and `$10` alone.
    pub math_text_single_dollar: bool,
    /// `{% … %}` / `{{ … }}` template tags, multi-line capable.
    /// Never interpreted, kept lossless.
    pub liquid: bool,
    /// `[[target]]` wiki links, alias-less minimal form, printed verbatim.
    pub wiki_link: bool,

    /// `::: … :::` container directives.
    /// Fence lines are kept verbatim (dialects disagree on their grammar);
    /// only children are markdown.
    pub container_directive: bool,

    /// MDX `import` / `export` statements at flow start.
    pub mdx_esm: bool,
    /// MDX `{expr}` as its own flow block.
    pub mdx_expression_flow: bool,
    /// MDX `{expr}` in text.
    pub mdx_expression_text: bool,
    /// MDX JSX elements at flow start.
    pub mdx_jsx_flow: bool,
    /// MDX JSX elements in text.
    pub mdx_jsx_text: bool,
}

impl Constructs {
    /// Markdown mode: CommonMark + GFM + Prettier's extensions + directives.
    pub fn markdown() -> Self {
        Self {
            autolink: true,
            code_indented: true,
            html_flow: true,
            html_text: true,
            gfm_autolink_literal: true,
            gfm_footnote: true,
            gfm_strikethrough: true,
            gfm_strikethrough_single_tilde: false,
            gfm_table: true,
            gfm_task_list_item: true,
            math_flow: true,
            math_text: true,
            math_text_single_dollar: false,
            liquid: true,
            wiki_link: true,
            container_directive: true,
            mdx_esm: false,
            mdx_expression_flow: false,
            mdx_expression_text: false,
            mdx_jsx_flow: false,
            mdx_jsx_text: false,
        }
    }

    /// MDX mode: `autolink` / `code_indented` / `html_flow` / `html_text` off, the `mdx_*` family on.
    /// Unlike markdown mode, parsing can emit diagnostics (MDX has syntax errors; CommonMark does not).
    ///
    /// TODO: Not usable yet: the `mdx_*` constructs are unimplemented,
    /// and disabling `code_indented` must also lift micromark's 4-space/3-column indent limits engine-wide (currently hardcoded),
    /// so this preset misparses e.g. `    # hi`.
    ///
    /// NOTE: Design:
    /// - Expression boundaries need JavaScript lexing (`{"}"}`, `{/* } */}`, template literals),
    ///   so this preset lives behind an `mdx` cargo feature that adds `oxc_parser` as an optional dependency.
    ///   No injection point: the scanner is this crate's own module, tested here.
    ///   The oxc workspace patches `oxc_parser` to its path crate, as it does `oxc_allocator`.
    /// - Semantics follow Prettier's MDX v3 parser (prettier/prettier#18533, micromark-extension-mdx-*):
    ///   - `{expr}` (flow, text, JSX attribute values): at each candidate `}`,
    ///     the text so far must be a complete expression (`Parser::parse_expression`, which rejects trailing content);
    ///     otherwise continue to the next `}`, and fail at EOF.
    ///   - `import` / `export`: ends at a blank line unless the parse error is at the end of input
    ///     (label start == length, or an `Unterminated ...` lexer error), then continue past it.
    ///     Prettier's `dummyAcorn` does not validate the body, so neither do we.
    ///   - JSX tags are lexed here; only their `{...}` attribute values consult the scanner.
    ///   - A hand-written brace scanner would agree on every input Prettier can format
    ///     (they differ only inside invalid JS, where Prettier throws),
    ///     which is why `oxc_lexer`, once published, can replace the probing without changing fixtures.
    pub fn mdx() -> Self {
        Self {
            autolink: false,
            code_indented: false,
            html_flow: false,
            html_text: false,
            mdx_esm: true,
            mdx_expression_flow: true,
            mdx_expression_text: true,
            mdx_jsx_flow: true,
            mdx_jsx_text: true,
            ..Self::markdown()
        }
    }
}

impl Default for Constructs {
    fn default() -> Self {
        Self::markdown()
    }
}

/// Options for [`Parser`](crate::Parser).
#[derive(Clone, Copy, Debug, Default, PartialEq, Eq)]
pub struct ParserOptions {
    pub constructs: Constructs,
}

impl ParserOptions {
    /// Markdown mode (the default): [`Constructs::markdown`].
    pub fn markdown() -> Self {
        Self { constructs: Constructs::markdown() }
    }

    /// MDX mode: [`Constructs::mdx`].
    pub fn mdx() -> Self {
        Self { constructs: Constructs::mdx() }
    }
}