bnf_rules!

LR(1) parser generator

Generate LR(1) parser at compilation time.

use bnf_rules::bnf_rules_macro::bnf_rules;

// Grammar
bnf_rules!(
    source   ::= expr
    expr     ::= factor { "+" factor }
    factor   ::= "-" primary | primary
    primary  ::= "(" expr ")" | number
    number   ::= r"\d+" // regex
);

pub fn parse() {

    // A function named "parse_source" is automatically generated.
    let ast_node: Result<ASTNode, ParseError> = parse_source("(100 + 200) + -100");
    dbg!(ast_node.unwrap());

}

Usage

bnf_rules = "0.1.5"

Extended BNF

Form	Semantic
source	An entire input source.
ident	A non-terminal symbol named "ident".
"something"	A terminal symbol for text.
r"\d+"	A terminal symbol for regex.
fn (function_name)	A custom tokenizer with user function.1
{ pattern }	Zero or more repetitions of "pattern".
[ pattern ]	"pattern" or null.
pattern1 | pattern2	"pattern1" or "pattern2".
( patterns )	A group of patterns.

Example 1: https://github.com/bea4dev/bnf_rules/blob/master/src/lib.rs

Example 2: https://github.com/bea4dev/catla/blob/master/catla_parser/src/grammar.rs

Footnotes

1. Generic parameters are also available. ↩