✨ feat(lang): add coalesce operator (??) support #706
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Add support for the null coalescing operator (??) to the mq language. The operator provides a concise way to handle null/none values by returning the right operand when the left operand is null or none. - Add COALESCE constant to ast/constants.rs - Implement TokenKind::Coalesce in lexer - Add coalesce operator parsing with precedence level 6 - Implement coalesce builtin function in eval/builtin.rs - Include comprehensive test cases for operator and function behavior - Add documentation for coalesce function
CodSpeed Performance ReportMerging #706 will not alter performanceComparing Summary
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Pull Request Overview
This PR adds support for the null coalescing operator (??) to the mq language, providing a concise way to handle null/none values by returning the right operand when the left operand is null or none.
Key changes:
- Introduces
TokenKind::Coalescefor lexer support of the??operator - Implements coalesce operator parsing with precedence level 6 (same as range operator)
- Adds
COALESCEbuiltin function that returns the first non-None value from two arguments
Reviewed Changes
Copilot reviewed 8 out of 8 changed files in this pull request and generated 2 comments.
Show a summary per file
| File | Description |
|---|---|
| crates/mq-lang/src/lexer/token.rs | Adds TokenKind::Coalesce variant and its display implementation, reorganizes enum variants alphabetically |
| crates/mq-lang/src/lexer.rs | Adds coalesce token parser and includes it in punctuation parsing |
| crates/mq-lang/src/eval/builtin.rs | Implements COALESCE builtin function with documentation and hash mapping |
| crates/mq-lang/src/eval.rs | Adds comprehensive test cases for coalesce function behavior |
| crates/mq-lang/src/cst/parser.rs | Adds coalesce binary operation support to CST parser with test case |
| crates/mq-lang/src/cst/node.rs | Adds BinaryOp::Coalesce variant to node types |
| crates/mq-lang/src/ast/parser.rs | Implements coalesce operator precedence and AST parsing with extensive test coverage |
| crates/mq-lang/src/ast/constants.rs | Defines COALESCE constant for the operator name |
| alt(( | ||
| and, or, l_paren, r_paren, l_brace, r_brace, comma, colon, semi_colon, l_bracket, | ||
| and, or, coalesce, l_paren, r_paren, l_brace, r_brace, comma, colon, semi_colon, l_bracket, | ||
| r_bracket, question, pipe, |
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The coalesce parser should be ordered by precedence or token length. Since ?? is two characters and ? is one character, coalesce should come before question in the alt() parser to ensure proper tokenization of ?? before attempting to parse it as two separate ? tokens.
| r_bracket, question, pipe, | |
| r_bracket, pipe, question, |
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Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
| fn punctuations(input: Span) -> IResult<Span, Token> { | ||
| alt(( | ||
| and, or, l_paren, r_paren, l_brace, r_brace, comma, colon, semi_colon, l_bracket, | ||
| and, or, coalesce, l_paren, r_paren, l_brace, r_brace, comma, colon, semi_colon, l_bracket, |
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The coalesce parser should be placed after question in the alt() chain to ensure proper parsing precedence. Since ?? starts with ?, the single ? parser might consume the first character before ?? can be matched.
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Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
| [a, b] => { | ||
| if a.is_none() { | ||
| Ok(std::mem::take(b)) | ||
| } else { | ||
| Ok(std::mem::take(a)) | ||
| } | ||
| } |
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The coalesce function implementation lacks documentation explaining its null coalescing behavior. Add a doc comment describing that it returns the first non-None value from the two arguments.
Copilot uses AI. Check for mistakes.
Add support for the null coalescing operator (??) to the mq language. The operator provides a concise way to handle null/none values by returning the right operand when the left operand is null or none.