glc

This crate's aim is to generate random expressions based on a context-free grammar.

The acronym stands for "gramática livre de contexto" (context-free grammar).

How to Use

```rust use glc::{Grammar, torrule, ntseqrule};

let grammar = Grammar( // starting symbol "S".into(),

// vector of rules
vec![
    // a rule that generates a sequence of non-terminals: "A B"
    nt_seq_rule!("S" => "A", "B"),
    nt_seq_rule!("B" => "A", "B", "N"),
    nt_seq_rule!("B" => "E"),
    t_or_rule!("E" => ""),

    // a rule that is an "or" of terminals: any letter from a-z
    t_or_rule!(
        "A" => "a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k",
               "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v",
               "w", "x", "y", "z"
    ),
    t_or_rule!("N" => "0", "1", "2", "3", "4", "5", "6", "7", "8", "9"),
],

)

// generate a random string with this grammar println!("{}", grammar.gen()); ```

A simplified version of the macro above is available:

``rust // You may need to tune this parameter depending on how large is your grammar, // since thegrammar` macro is recursive.

![recursion_limit = "256"]

use glc::grammar;

let _grammar = grammar!{ // The first non-terminal seen (head of the 1st rule) will be // the starting symbol (in this case: S). S => A B; B => A B N; B => E; E => ""; // Or transform a non-terminal in one among many terminals A => "a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z"; N => "0", "1", "2", "3", "4", "5", "6", "7", "8", "9" };

```

For a real-life example take a look at mexe.

Links