Add quick-and-dirty binary for loading and evaluating grammars

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "purrchance"
-version = "0.1.0"
+version = "0.2.0"
 authors = ["xenofem <xenofem@xeno.science>"]
 description = "An unofficial Rust implementation of the Perchance grammar engine"
 repository = "https://git.xeno.science/xenofem/purrchance"

src/bin/purrchance.rs

@@ -0,0 +1,25 @@
+use purrchance::*;
+use purrchance::parser::*;
+
+use std::env;
+use std::fs::read_to_string;
+use std::process::exit;
+
+fn main() {
+    let args: Vec<String> = env::args().collect();
+
+    if args.len() < 2 {
+        eprintln!("too few arguments!");
+        exit(1);
+    }
+
+    let raw_grammar = read_to_string(&args[1]).unwrap();
+    let grammar = load_grammar(&raw_grammar);
+    if args.len() < 3 {
+        eprintln!("{:?}", grammar);
+        exit(0);
+    }
+
+    let sym = Symbol::NonTerminal(args[2].clone());
+    println!("{}", sym.eval(&grammar).unwrap());
+}

src/lib.rs

@@ -10,6 +10,7 @@ pub trait Purrchance {
     fn eval(&self, g: &Grammar) -> Option<String>;
 }
 
+#[derive(Debug)]
 pub enum Symbol {
     Terminal(String),
     NonTerminal(String),
@@ -24,6 +25,7 @@ impl Purrchance for Symbol {
     }
 }
 
+#[derive(Debug)]
 pub struct Expr(Vec<Symbol>);
 
 impl Purrchance for Expr {
@@ -32,6 +34,7 @@ impl Purrchance for Expr {
     }
 }
 
+#[derive(Debug)]
 pub struct List(Vec<(Expr, f64)>);
 
 impl Purrchance for List {
@@ -40,6 +43,7 @@ impl Purrchance for List {
     }
 }
 
+#[derive(Debug)]
 pub struct Grammar(HashMap<String,List>);
 
 #[cfg(test)]
@@ -142,6 +146,19 @@ test
 test
   foo ^1000000
 	bar ^1/1000000
+");
+        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
 ");
         let nt = Symbol::NonTerminal(String::from("test"));
         assert_eq!(nt.eval(&g), Some(String::from("foo")));