bimr-engine/grammar

Grammar

bimr.bnf is a human-readable reference describing the BIMR language grammar in BNF notation. It is not consumed by the build — it documents the rules that the lexer and parser implement in code.

How the pipeline works

Lexer (lexer/src/lexer.rs) — powered by logos. The grammar is expressed directly as Rust attributes on the Token enum: regex patterns for identifiers, integers, and strings; literal patterns for punctuation (=, ,, (, )). logos generates the tokeniser at compile time — no external grammar file is involved.

Parser (parser/src/parser.rs) — powered by chumsky. Consumes the token stream produced by the lexer and builds an AST. The grammar rules map directly to parser combinators:

BNF rule	Parser combinator
program ::= statement*	statement().repeated().collect()
statement ::= identifier = expression	identifier().then_ignore(just(Equal)).then(expression())
expression ::= function_call | identifier | integer | string	choice((function_call, base_expr()))
function_call ::= identifier ( arguments )	identifier().then(...).delimited_by(LeftParen, RightParen)
arguments ::= expression (, expression)*	base_expr().separated_by(just(Comma))

Summary

bimr.bnf serves as a concise spec to understand the language at a glance. The source of truth is the Rust code in lexer/ and parser/.