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| -rw-r--r-- | src/construct/code_indented.rs | 190 |
1 files changed, 190 insertions, 0 deletions
diff --git a/src/construct/code_indented.rs b/src/construct/code_indented.rs new file mode 100644 index 0000000..6bf089b --- /dev/null +++ b/src/construct/code_indented.rs @@ -0,0 +1,190 @@ +//! Code (indented) is a construct that occurs in the flow content type. +//! +//! It forms with the following BNF: +//! +//! ```bnf +//! code_indented ::= indented_filled_line *( eol *( blank_line eol ) indented_filled_line ) +//! +//! ; Restriction: at least one `code` must not be whitespace. +//! indented_filled_line ::= 4space_or_tab *code +//! blank_line ::= *space_or_tab +//! eol ::= '\r' | '\r\n' | '\n' +//! code ::= . ; any unicode code point (other than line endings). +//! space_or_tab ::= ' ' | '\t' +//! ``` +//! +//! Code (indented) relates to both the `<pre>` and the `<code>` elements in +//! HTML. +//! See [*§ 4.4.3 The `pre` element*][html-pre] and the [*§ 4.5.15 The `code` +//! element*][html-code] in the HTML spec for more info. +//! +//! In markdown, it is also possible to use code (text) in the text content +//! type. +//! It is also possible to create code with the [code (fenced)][code-fenced] +//! construct. +//! That construct is more explicit, more similar to code (text), and has +//! support for specifying the programming language that the code is in, so it +//! is recommended to use that instead of indented code. +//! +//! ## References +//! +//! * [`code-indented.js` in `micromark`](https://github.com/micromark/micromark/blob/main/packages/micromark-core-commonmark/dev/lib/code-indented.js) +//! * [*§ 4.4 Indented code blocks* in `CommonMark`](https://spec.commonmark.org/0.30/#indented-code-blocks) +//! +//! [code-fenced]: crate::construct::code_fenced +//! [html-pre]: https://html.spec.whatwg.org/multipage/grouping-content.html#the-pre-element +//! [html-code]: https://html.spec.whatwg.org/multipage/text-level-semantics.html#the-code-element +//! +//! <!-- To do: link `flow`, `code_text` --> + +use crate::constant::TAB_SIZE; +use crate::tokenizer::{Code, State, StateFnResult, TokenType, Tokenizer}; + +/// Start of code (indented). +/// +/// ```markdown +/// | asd +/// ``` +pub fn start(tokenizer: &mut Tokenizer, code: Code) -> StateFnResult { + match code { + Code::VirtualSpace | Code::Char(' ' | '\t') => { + tokenizer.enter(TokenType::CodeIndented); + tokenizer.enter(TokenType::CodeIndentedPrefixWhitespace); + indent(tokenizer, code, 0) + } + _ => (State::Nok, None), + } +} + +/// Inside the initial whitespace. +/// +/// ```markdown +/// | asd +/// | asd +/// | asd +/// |asd +/// ``` +/// +/// > **Parsing note**: it is not needed to check if this first line is a +/// > filled line (that it has a non-whitespace character), because blank lines +/// > are parsed already, so we never run into that. +fn indent(tokenizer: &mut Tokenizer, code: Code, size: usize) -> StateFnResult { + match code { + _ if size == TAB_SIZE => { + tokenizer.exit(TokenType::CodeIndentedPrefixWhitespace); + at_break(tokenizer, code) + } + Code::VirtualSpace | Code::Char(' ' | '\t') => { + tokenizer.consume(code); + ( + State::Fn(Box::new(move |tokenizer, code| { + indent(tokenizer, code, size + 1) + })), + None, + ) + } + _ => (State::Nok, None), + } +} + +/// At a break. +/// +/// ```markdown +/// |asd +/// asd| +/// ``` +fn at_break(tokenizer: &mut Tokenizer, code: Code) -> StateFnResult { + match code { + Code::None => after(tokenizer, code), + Code::CarriageReturnLineFeed | Code::Char('\n' | '\r') => tokenizer + .attempt(further_start, |ok| { + Box::new(if ok { at_break } else { after }) + })(tokenizer, code), + _ => { + tokenizer.enter(TokenType::CodeFlowChunk); + content(tokenizer, code) + } + } +} + +/// Inside code content. +/// +/// ```markdown +/// |ab +/// a|b +/// ab| +/// ``` +fn content(tokenizer: &mut Tokenizer, code: Code) -> StateFnResult { + match code { + Code::None | Code::CarriageReturnLineFeed | Code::Char('\n' | '\r') => { + tokenizer.exit(TokenType::CodeFlowChunk); + at_break(tokenizer, code) + } + _ => { + tokenizer.consume(code); + (State::Fn(Box::new(content)), None) + } + } +} + +/// After indented code. +/// +/// ```markdown +/// ab| +/// ``` +fn after(tokenizer: &mut Tokenizer, code: Code) -> StateFnResult { + tokenizer.exit(TokenType::CodeIndented); + (State::Ok, Some(vec![code])) +} + +/// Right at a line ending, trying to parse another indent. +/// +/// ```markdown +/// ab| +/// cd +/// ``` +fn further_start(tokenizer: &mut Tokenizer, code: Code) -> StateFnResult { + // To do: `nok` if lazy line. + match code { + Code::CarriageReturnLineFeed | Code::Char('\n' | '\r') => { + tokenizer.enter(TokenType::LineEnding); + tokenizer.consume(code); + tokenizer.exit(TokenType::LineEnding); + (State::Fn(Box::new(further_start)), None) + } + Code::VirtualSpace | Code::Char(' ' | '\t') => { + tokenizer.enter(TokenType::CodeIndentedPrefixWhitespace); + further_indent(tokenizer, code, 0) + } + _ => (State::Nok, None), + } +} + +/// Inside further whitespace. +/// +/// ```markdown +/// asd +/// | asd +/// ``` +fn further_indent(tokenizer: &mut Tokenizer, code: Code, size: usize) -> StateFnResult { + match code { + _ if size == TAB_SIZE => { + tokenizer.exit(TokenType::CodeIndentedPrefixWhitespace); + (State::Ok, Some(vec![code])) + } + Code::VirtualSpace | Code::Char(' ' | '\t') => { + tokenizer.consume(code); + ( + State::Fn(Box::new(move |tokenizer, code| { + further_indent(tokenizer, code, size + 1) + })), + None, + ) + } + Code::CarriageReturnLineFeed | Code::Char('\n' | '\r') => { + tokenizer.exit(TokenType::CodeIndentedPrefixWhitespace); + further_start(tokenizer, code) + } + _ => (State::Nok, None), + } +} |