bnf_rules 0.1.7

LR(1) parser generator
Documentation

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 = "0.1.7"

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.

[^1]: Generic parameters are also available.

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