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|
use alloc::string::String;
/// Signal used as feedback when parsing MDX ESM/expressions.
#[derive(Clone, Debug)]
pub enum Signal {
/// A syntax error.
///
/// `markdown-rs` will crash with error message `String`, and convert the
/// `usize` (byte offset into `&str` passed to `MdxExpressionParse` or
/// `MdxEsmParse`) to where it happened in the whole document.
///
/// ## Examples
///
/// ```rust ignore
/// Signal::Error("Unexpected `\"`, expected identifier".into(), 1)
/// ```
Error(String, usize),
/// An error at the end of the (partial?) expression.
///
/// `markdown-rs` will either crash with error message `String` if it
/// doesn’t have any more text, or it will try again later when more text
/// is available.
///
/// ## Examples
///
/// ```rust ignore
/// Signal::Eof("Unexpected end of file in string literal".into())
/// ```
Eof(String),
/// Done, successfully.
///
/// `markdown-rs` knows that this is the end of a valid expression/esm and
/// continues with markdown.
///
/// ## Examples
///
/// ```rust ignore
/// Signal::Ok
/// ```
Ok,
}
/// Signature of a function that parses MDX ESM.
///
/// Can be passed as `mdx_esm_parse` in
/// [`ParseOptions`][crate::configuration::ParseOptions] to support
/// ESM according to a certain grammar (typically, a programming language).
pub type EsmParse = dyn Fn(&str) -> Signal;
/// Expression kind.
#[derive(Clone, Debug)]
pub enum ExpressionKind {
/// Kind of expressions in prose.
///
/// ```mdx
/// > | # {Math.PI}
/// ^^^^^^^^^
/// |
/// > | {Math.PI}
/// ^^^^^^^^^
/// ```
Expression,
/// Kind of expressions as attributes.
///
/// ```mdx
/// > | <a {...b}>
/// ^^^^^^
/// ```
AttributeExpression,
/// Kind of expressions as attribute values.
///
/// ```mdx
/// > | <a b={c}>
/// ^^^
/// ```
AttributeValueExpression,
}
/// Signature of a function that parses MDX expressions.
///
/// Can be passed as `mdx_expression_parse` in
/// [`ParseOptions`][crate::configuration::ParseOptions] to support
/// expressions according to a certain grammar (typically, a programming
/// language).
///
pub type ExpressionParse = dyn Fn(&str, &ExpressionKind) -> Signal;
#[cfg(test)]
mod tests {
use super::*;
use alloc::boxed::Box;
#[test]
fn test_mdx_expression_parse() {
fn func(_value: &str, _kind: &ExpressionKind) -> Signal {
Signal::Ok
}
let func_accepting = |_a: Box<ExpressionParse>| true;
assert!(
matches!(func("a", &ExpressionKind::Expression), Signal::Ok),
"should expose an `ExpressionParse` type (1)"
);
assert!(
func_accepting(Box::new(func)),
"should expose an `ExpressionParse` type (2)"
);
}
#[test]
fn test_mdx_esm_parse() {
fn func(_value: &str) -> Signal {
Signal::Ok
}
let func_accepting = |_a: Box<EsmParse>| true;
assert!(
matches!(func("a"), Signal::Ok),
"should expose an `EsmParse` type (1)"
);
assert!(
func_accepting(Box::new(func)),
"should expose an `EsmParse` type (2)"
);
}
}
|
