Refactoring and cleanup for parser module

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "purrchance"
-version = "0.2.0"
+version = "0.3.0"
 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

@@ -14,7 +14,7 @@ fn main() {
     }
 
     let raw_grammar = read_to_string(&args[1]).unwrap();
-    let grammar = load_grammar(&raw_grammar);
+    let grammar = load_grammar(&raw_grammar).unwrap();
     if args.len() < 3 {
         eprintln!("{:?}", grammar);
         exit(0);

src/lib.rs

@@ -115,7 +115,7 @@ mod tests {
 
     #[test]
     fn eval_loaded_grammar() {
-        let g = load_grammar("test\n  foo\n");
+        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")));
     }
@@ -125,7 +125,7 @@ mod tests {
         let g = load_grammar("// testing
 test
   foo // blah blah
-// isn't this fun?");
+// isn't this fun?").unwrap();
         let nt = Symbol::NonTerminal(String::from("test"));
         assert_eq!(nt.eval(&g), Some(String::from("foo")));
     }
@@ -135,7 +135,7 @@ test
         let g = load_grammar("// testing
 test
   foo ^100
-// isn't this fun?");
+// isn't this fun?").unwrap();
         let nt = Symbol::NonTerminal(String::from("test"));
         assert_eq!(nt.eval(&g), Some(String::from("foo")));
     }
@@ -146,11 +146,32 @@ test
 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("
@@ -159,7 +180,7 @@ test
 
 test1
   foo
-");
+").unwrap();
         let nt = Symbol::NonTerminal(String::from("test"));
         assert_eq!(nt.eval(&g), Some(String::from("foo")));
     }

src/parser.rs

@@ -11,24 +11,7 @@ use nom::multi::*;
 use nom::number::complete::*;
 use nom::sequence::*;
 
-fn nonterminal(input: &str) -> IResult<&str, Symbol> {
+fn take_until_any<T, Input, Error: ParseError<Input>>(tags: Vec<T>) -> impl Fn(Input) -> IResult<Input, Input, Error>
-    map(delimited(tag("["), nonterminal_name, tag("]")), Symbol::NonTerminal)(input)
-}
-fn weight(input: &str) -> IResult<&str, f64> {
-    preceded(tag("^"), alt((double, rat)))(input)
-}
-fn comment(input: &str) -> IResult<&str, ()> {
-    map(tuple((tag("//"), is_not("\n"))), |_| ())(input)
-}
-fn whitespace(input: &str) -> IResult<&str, ()> {
-    map(take_while(|c| (c == ' ' || c == '\t')), |_| ())(input)
-}
-
-fn empty_line(input: &str) -> IResult<&str, ()> {
-    map(tuple((whitespace, opt(comment), tag("\n"))), |_| ())(input)
-}
-
-pub fn take_until_any<T, Input, Error: ParseError<Input>>(tags: Vec<T>) -> impl Fn(Input) -> IResult<Input, Input, Error>
 where
     Input: InputTake + FindSubstring<T>,
     T: InputLength + Clone,
@@ -59,6 +42,10 @@ fn nonterminal_name(input: &str) -> IResult<&str, String> {
     Ok((input, String::from(head.to_owned() + tail)))
 }
 
+fn nonterminal(input: &str) -> IResult<&str, Symbol> {
+    map(delimited(tag("["), nonterminal_name, tag("]")), Symbol::NonTerminal)(input)
+}
+
 fn rat(input: &str) -> IResult<&str, f64> {
     let (input, num) = double(input)?;
     let (input, _) = tag("/")(input)?;
@@ -67,17 +54,43 @@ fn rat(input: &str) -> IResult<&str, f64> {
     Ok((input, num / denom))
 }
 
+fn weight(input: &str) -> IResult<&str, f64> {
+    preceded(tag("^"), alt((rat, double)))(input)
+}
+
+fn comment(input: &str) -> IResult<&str, ()> {
+    map(tuple((tag("//"), is_not("\n"))), |_| ())(input)
+}
+
+fn whitespace(input: &str) -> IResult<&str, ()> {
+    map(take_while(|c| (c == ' ' || c == '\t')), |_| ())(input)
+}
+
+fn eol(input: &str) -> IResult<&str, ()> {
+    map(alt((tag("\n"), all_consuming(take(0usize)))), |_| ())(input)
+}
+
+fn empty_lines(input: &str) -> IResult<&str, ()> {
+    map(
+        tuple((
+            many0(tuple((whitespace, opt(comment), tag("\n")))),
+            opt(tuple((whitespace, opt(comment), eol))),
+        )),
+        |_| ()
+    )(input)
+}
+
 fn expr(input: &str) -> IResult<&str, (Expr, f64)> {
     let (input, (_, _, syms, _, weight, _, _, _, _)) = tuple((
-        many0(empty_line),
+        empty_lines,
         alt((tag("  "), tag("\t"))),
         many1(alt((terminal, nonterminal))),
         whitespace,
         opt(weight),
         whitespace,
         opt(comment),
-        tag("\n"),
+        eol,
-        many0(empty_line),
+        empty_lines,
     ))(input)?;
 
     Ok((input, (Expr(syms), weight.unwrap_or(1.0))))
@@ -85,7 +98,7 @@ fn expr(input: &str) -> IResult<&str, (Expr, f64)> {
 
 fn list(input: &str) -> IResult<&str, (String, List)> {
     let (input, (_, name, _, _, _, exprs)) = tuple((
-        many0(empty_line),
+        empty_lines,
         nonterminal_name,
         whitespace,
         opt(comment),
@@ -102,6 +115,6 @@ fn grammar(input: &str) -> IResult<&str, Grammar> {
     Ok((input, Grammar(HashMap::from_iter(lists.into_iter()))))
 }
 
-pub fn load_grammar(input: &str) -> Grammar {
+pub fn load_grammar(input: &str) -> Result<Grammar, Err<(&str, ErrorKind)>> {
-    grammar(input).unwrap().1
+    all_consuming(grammar)(input).map(|(_, g)| g)
 }