Module lexer 

Functions

classify_keyword

Classify an identifier string as a keyword or plain IDENT.

lex

Lex source into a sequence of (SyntaxKind, slice) pairs.

lex_punctuation

Try to lex punctuation starting at pos. Returns (kind, advance). Handles all greedy multi-char disambiguation. None means the byte isn’t punctuation at all (falls through to ident/digit/error handling).