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extern crate nom; extern crate rand; pub mod parser; use rand::{seq::SliceRandom, thread_rng}; use std::collections::HashMap; pub trait Purrchance { fn eval(&self, g: &Grammar) -> Option<String>; } #[derive(Clone, Debug)] pub enum Symbol { Terminal(String), NonTerminal(String), } impl Purrchance for Symbol { fn eval(&self, g: &Grammar) -> Option<String> { match self { Symbol::Terminal(s) => Some(String::from(s)), Symbol::NonTerminal(label) => g.0.get(label)?.eval(g), } } } #[derive(Clone, Debug)] pub struct Expr(Vec<Symbol>); impl Purrchance for Expr { fn eval(&self, g: &Grammar) -> Option<String> { Some(self.0.iter().map(|sym| sym.eval(g)).collect::<Option<Vec<String>>>()?.join("")) } } #[derive(Clone, Debug)] pub struct List(Vec<(Expr, f64)>); impl Purrchance for List { fn eval(&self, g: &Grammar) -> Option<String> { self.0.choose_weighted(&mut thread_rng(), |item| item.1).ok()?.0.eval(g) } } #[derive(Clone, Debug)] pub struct Grammar(HashMap<String,List>); #[cfg(test)] mod tests { use super::*; use parser::*; #[test] fn eval_terminal() { let sym = Symbol::Terminal("hello world".to_string()); let g = Grammar(HashMap::new()); assert_eq!(sym.eval(&g), Some("hello world".to_string())); } #[test] fn eval_terminals_expr() { let sym1 = Symbol::Terminal("hell".to_string()); let sym2 = Symbol::Terminal("o world".to_string()); let expr = Expr(vec![sym1, sym2]); let g = Grammar(HashMap::new()); assert_eq!(expr.eval(&g), Some("hello world".to_string())); } #[test] fn eval_single_terminals_expr_list() { let sym1 = Symbol::Terminal("hell".to_string()); let sym2 = Symbol::Terminal("o world".to_string()); let expr = Expr(vec![sym1, sym2]); let list = List(vec![(expr, 1.0)]); let g = Grammar(HashMap::new()); assert_eq!(list.eval(&g), Some("hello world".to_string())); } #[test] fn eval_multiple_terminals_expr_list() { let sym1 = Symbol::Terminal("hello".to_string()); let sym2 = Symbol::Terminal("goodbye".to_string()); let list = List(vec![(Expr(vec![sym1]), 1.0), (Expr(vec![sym2]), 1.0)]); let g = Grammar(HashMap::new()); assert!(vec![Some("hello".to_string()), Some("goodbye".to_string())].contains(&list.eval(&g))); } #[test] fn eval_empty_list() { let list = List(vec![]); let g = Grammar(HashMap::new()); assert_eq!(list.eval(&g), None); } #[test] fn eval_valid_nonterminal() { let term = Symbol::Terminal("hello world".to_string()); let list = List(vec![(Expr(vec![term]), 1.0)]); let mut g = Grammar(HashMap::new()); g.0.insert("output".to_string(), list); let nt = Symbol::NonTerminal("output".to_string()); assert_eq!(nt.eval(&g), Some("hello world".to_string())); } #[test] fn eval_missing_nonterminal() { let term = Symbol::Terminal("hello world".to_string()); let list = List(vec![(Expr(vec![term]), 1.0)]); let mut g = Grammar(HashMap::new()); g.0.insert("output".to_string(), list); let nt = Symbol::NonTerminal("missing".to_string()); assert_eq!(nt.eval(&g), None); } #[test] fn eval_loaded_grammar() { let g = load_grammar("test\n foo\n").unwrap(); let nt = Symbol::NonTerminal(String::from("test")); assert_eq!(nt.eval(&g), Some(String::from("foo"))); } #[test] fn eval_loaded_grammar_comments() { let g = load_grammar("// testing test foo // blah blah // isn't this fun?").unwrap(); let nt = Symbol::NonTerminal(String::from("test")); assert_eq!(nt.eval(&g), Some(String::from("foo"))); } #[test] fn eval_loaded_grammar_comments_weights() { let g = load_grammar("// testing test foo ^100 // isn't this fun?").unwrap(); let nt = Symbol::NonTerminal(String::from("test")); assert_eq!(nt.eval(&g), Some(String::from("foo"))); } #[test] fn eval_loaded_grammar_comments_fraction_weights_tabs() { let g = load_grammar(" test foo ^1000000 bar ^1/1000000 ").unwrap(); let nt = Symbol::NonTerminal(String::from("test")); assert_eq!(nt.eval(&g), Some(String::from("foo"))); } #[test] fn eval_loaded_grammar_comments_fraction_weights_tabs2() { let g = load_grammar(" test bar ^1/1000000 foo ^1000000 ").unwrap(); let nt = Symbol::NonTerminal(String::from("test")); assert_eq!(nt.eval(&g), Some(String::from("foo"))); } #[test] fn eval_loaded_grammar_comments_fraction_weights3() { let g = load_grammar(" test bar ^1/1000000000 foo ^1/2 ").unwrap(); let nt = Symbol::NonTerminal(String::from("test")); assert_eq!(nt.eval(&g), Some(String::from("foo"))); } #[test] fn eval_loaded_grammar_multiple_lists() { let g = load_grammar(" test [test1] test1 foo ").unwrap(); let nt = Symbol::NonTerminal(String::from("test")); assert_eq!(nt.eval(&g), Some(String::from("foo"))); } #[test] fn eval_loaded_grammar_no_trailing_newline() { let g = load_grammar("test foo").unwrap(); let nt = Symbol::NonTerminal(String::from("test")); assert_eq!(nt.eval(&g), Some(String::from("foo"))); } }