tree fb628f9aa5e539abc5bd2e64240bb0211707be0b
parent ad74392541b9a72b521e56673cfdd013532fbd4a
author Sketch🕴️ <skallywag@sketch.dev> 1772291616 +0400
committer Sketch🕴️ <skallywag@sketch.dev> 1772291616 +0400

parser: implement recursive-descent parser with tests

- Parse([]token.Token) (ast.Node, error) converts tokens to AST
- Grammar: expr → term ((+|-) term)*, term → factor ((*|/) factor)*, factor → NUMBER | '(' expr ')'
- Correct operator precedence (* / before + -)
- Left-associative operators
- Error handling: empty input, missing/unexpected parens, trailing tokens, consecutive operators
- 19 unit tests covering success and error cases