Cargo.toml

@@ -6,5 +6,3 @@ edition = "2021"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-arbitrary = "1.2.0"
-proptest = "1.0.0"

README.md

@@ -1,5 +0,0 @@
-# Rust Parser Combinator
-
-This is a super-basic Rust parser combinator library I wrote mostly
-as an exercise for myself. Inspired by [nom](https://github.com/rust-bakery/nom)
-and [chumsky](https://github.com/zesterer/chumsky)

src/combinators/repeated.rs

@@ -1,5 +1,5 @@
 use crate::combinators::separated_by::SeparatedBy;
-use crate::parser::{BoxedParser, ParseResult, Parser, ParserInput, Representation};
+use crate::parser::{BoxedParser, ParseResult, Parser, ParserInput};
 
 pub fn repeated<'a, P, I, O>(parser: P) -> Repeated<'a, I, O>
 where
@@ -83,8 +83,4 @@ where
 
         Ok((results, further_input))
     }
-
-    fn representation(&self) -> Representation {
-        Representation::new("NOT IMPL'D")
-    }
 }

src/combinators/separated_by.rs

@@ -1,5 +1,5 @@
 use crate::combinators::repeated::Repeated;
-use crate::parser::{BoxedParser, ParseResult, Parser, ParserInput, Representation};
+use crate::parser::{BoxedParser, ParseResult, Parser, ParserInput};
 
 pub struct SeparatedBy<'a, I, O>
 where
@@ -14,10 +14,6 @@ impl<'a, I, O> Parser<I, Vec<O>, I> for SeparatedBy<'a, I, O>
 where
     I: ParserInput + Clone + 'a,
 {
-    fn representation(&self) -> Representation {
-        Representation::new("NOT IMPL'D")
-    }
-
     fn parse(&self, input: I) -> ParseResult<I, Vec<O>, I> {
         let at_least = self.inner_repeated.at_least.unwrap_or(0);
         let at_most = self.inner_repeated.at_most.unwrap_or(u16::MAX);

src/lib.rs

@@ -4,4 +4,221 @@ mod parser;
 pub mod primitives;
 pub mod sequence;
 
+#[cfg(test)]
 pub use parser::{ParseResult, Parser, ParserInput};
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::choice::choice;
+    use crate::combinators::repeated;
+    use crate::primitives::{any_char, literal, literal_char, one_of, pred};
+    use crate::sequence::seq;
+
+    #[test]
+    fn test_parsing() {
+        let output = literal("a")("a yolo");
+        assert_eq!(output.unwrap(), ("a", " yolo"));
+    }
+
+    /*
+     * JSON BNF
+     * <JSON>     ::= <value>
+    <value>    ::= <object> | <array> | <boolean> | <string> | <number> | <null>
+    <array>    ::= "[" [<value>] {"," <value>}* "]"
+    <object>   ::= "{" [<property>] {"," <property>}* "}"
+    <property> ::= <string> ":" <value>
+    */
+    #[derive(Debug, Clone, PartialEq)]
+    enum JsonValue {
+        Null,
+        Bool(bool),
+        Str(String),
+        Num(f64),
+        Array(Vec<JsonValue>),
+        Object(Vec<(String, JsonValue)>),
+    }
+
+    trait JsonParser<'a, T>: Parser<&'a str, T, &'a str> {}
+    impl<'a, T, P> JsonParser<'a, T> for P where P: Parser<&'a str, T, &'a str> {}
+
+    fn json_null<'a>() -> impl JsonParser<'a, JsonValue> {
+        literal("null").to(JsonValue::Null)
+    }
+    fn json_bool<'a>() -> impl JsonParser<'a, JsonValue> {
+        choice((
+            literal("true").to(JsonValue::Bool(true)),
+            literal("false").to(JsonValue::Bool(false)),
+        ))
+    }
+
+    fn json_number() -> impl JsonParser<'static, JsonValue> {
+        let digit = || one_of("1234567890");
+        let digits = || repeated(digit()).at_least(1);
+
+        let json_number_inner = choice((
+            seq((digits(), literal(".").ignore_then(digits()).optional())).map(
+                |(mut digits, maybe_decimal)| {
+                    if let Some(decimal_digits) = maybe_decimal {
+                        digits.push(".");
+                        digits.extend(decimal_digits.into_iter());
+                    }
+                    digits.into_iter().collect::<String>()
+                },
+            ),
+            literal(".").ignore_then(digits()).map(|decimal_digits| {
+                let mut d = vec!["."];
+                d.extend(decimal_digits.into_iter());
+                d.into_iter().collect::<String>()
+            }),
+        ))
+        .map(|digits| digits.parse::<f64>().unwrap());
+
+        literal("-")
+            .optional()
+            .then(json_number_inner)
+            .map(|(maybe_sign, mut val)| {
+                if maybe_sign.is_some() {
+                    val *= -1.0;
+                }
+                JsonValue::Num(val)
+            })
+    }
+
+    fn json_string_raw() -> impl JsonParser<'static, String> {
+        seq((
+            literal_char('"'),
+            repeated(pred(any_char, |ch| *ch != '"')),
+            literal_char('"'),
+        ))
+        .map(|(_, s, _)| s.iter().cloned().collect::<String>())
+    }
+
+    fn json_string() -> impl JsonParser<'static, JsonValue> {
+        json_string_raw().map(JsonValue::Str)
+    }
+
+    fn whitespace() -> impl JsonParser<'static, ()> {
+        repeated(choice((
+            literal_char('\t'),
+            literal_char('\n'),
+            literal_char(' '),
+        )))
+        .to(())
+    }
+
+    fn json_array() -> impl JsonParser<'static, JsonValue> {
+        move |input| {
+            let val = json_value().surrounded_by(whitespace());
+
+            repeated(val)
+                .separated_by(literal(","), false)
+                .delimited(literal_char('['), literal_char(']'))
+                .map(JsonValue::Array)
+                .parse(input)
+        }
+    }
+
+    fn json_object() -> impl JsonParser<'static, JsonValue> {
+        move |input| {
+            let kv = json_string_raw()
+                .surrounded_by(whitespace())
+                .then_ignore(literal_char(':'))
+                .then(json_value().surrounded_by(whitespace()));
+
+            repeated(kv)
+                .separated_by(literal_char(','), false)
+                .delimited(literal_char('{'), literal_char('}'))
+                .map(JsonValue::Object)
+                .parse(input)
+        }
+    }
+
+    fn json_value() -> impl JsonParser<'static, JsonValue> {
+        choice((
+            json_null(),
+            json_bool(),
+            json_number(),
+            json_string(),
+            json_array(),
+            json_object(),
+        ))
+    }
+
+    #[test]
+    fn parse_json_primitives() {
+        assert_eq!(
+            json_string().parse(r#""yolo swagg""#).unwrap(),
+            (JsonValue::Str("yolo swagg".into()), "")
+        );
+
+        assert_eq!(
+            json_number().parse("-383").unwrap().0,
+            JsonValue::Num(-383f64)
+        );
+        assert_eq!(
+            json_number().parse("-.383").unwrap().0,
+            JsonValue::Num(-0.383)
+        );
+        assert_eq!(
+            json_number().parse(".383").unwrap().0,
+            JsonValue::Num(0.383)
+        );
+        assert_eq!(
+            json_number().parse("-1.383").unwrap().0,
+            JsonValue::Num(-1.383)
+        );
+    }
+
+    #[test]
+    fn parse_json_array() {
+        assert!(json_array().parse(r#"[ 4, 9, "ara",]"#).is_err());
+        assert_eq!(
+            json_array().parse("[[],[]]").unwrap().0,
+            JsonValue::Array(vec![JsonValue::Array(vec![]), JsonValue::Array(vec![])])
+        );
+        assert_eq!(
+            json_array().parse(r#"[  4,   9,   "foo"   ]"#).unwrap(),
+            (
+                JsonValue::Array(vec![
+                    JsonValue::Num(4.),
+                    JsonValue::Num(9.0),
+                    JsonValue::Str("foo".to_string())
+                ]),
+                ""
+            )
+        );
+        assert_eq!(
+            json_array().parse(r#"[8,null,[],5],{}"#).unwrap(),
+            (
+                JsonValue::Array(vec![
+                    JsonValue::Num(8.),
+                    JsonValue::Null,
+                    JsonValue::Array(vec![]),
+                    JsonValue::Num(5.),
+                ]),
+                ",{}"
+            )
+        );
+        assert_eq!(json_value().parse("true"), Ok((JsonValue::Bool(true), "")));
+    }
+
+    #[test]
+    fn parse_json_object() {
+        assert_eq!(
+            json_object().parse(r#"{ "a": 23}"#).unwrap().0,
+            JsonValue::Object(vec![("a".into(), JsonValue::Num(23.))])
+        );
+        assert_eq!(
+            json_object().parse(r#"{}"#).unwrap().0,
+            JsonValue::Object(vec![])
+        );
+    }
+
+    #[test]
+    fn parse_json() {
+        let test_json = include_str!("joplin-cfg.json");
+        let parsed_json = json_object().parse(test_json);
+        assert!(parsed_json.is_ok());
+    }
+}

src/parser/boxed_parser.rs

@@ -1,4 +1,4 @@
-use crate::parser::{ParseResult, Parser, ParserInput, Representation};
+use crate::parser::{ParseResult, Parser, ParserInput};
 
 pub struct BoxedParser<'a, I, O, E>
 where
@@ -22,9 +22,6 @@ where
 }
 
 impl<'a, I: ParserInput, O, E> Parser<I, O, E> for BoxedParser<'a, I, O, E> {
-    fn representation(&self) -> Representation {
-        Representation::new("NOT IMPL'D")
-    }
     fn parse(&self, input: I) -> ParseResult<I, O, E> {
         self.inner.parse(input)
     }

src/parser/mod.rs

@@ -1,25 +1,24 @@
 mod boxed_parser;
 mod named_parser;
-mod parser_input;
-mod representation;
 
 use std::rc::Rc;
 
 pub use boxed_parser::BoxedParser;
 pub use named_parser::NamedParser;
-pub use parser_input::ParserInput;
-pub use representation::Representation;
 
 pub type ParseResult<I, O, E> = Result<(O, I), E>;
 
+pub trait ParserInput: std::fmt::Debug {}
+
+impl ParserInput for &str {}
+impl ParserInput for String {}
+
 pub trait Parser<I, O, E>
 where
     I: ParserInput,
 {
     fn parse(&self, input: I) -> ParseResult<I, O, E>;
 
-    fn representation(&self) -> Representation;
-
     fn boxed<'a>(self) -> BoxedParser<'a, I, O, E>
     where
         Self: Sized + 'a,
@@ -145,23 +144,6 @@ where
     fn parse(&self, input: I) -> ParseResult<I, O, E> {
         self(input)
     }
-
-    fn representation(&self) -> Representation {
-        Representation::new("NOT IMPL'D")
-    }
-}
-
-impl<I: ParserInput, O, E, F> Parser<I, O, E> for (F, Representation)
-where
-    F: Fn(I) -> ParseResult<I, O, E>,
-{
-    fn parse(&self, input: I) -> ParseResult<I, O, E> {
-        self.0(input)
-    }
-
-    fn representation(&self) -> Representation {
-        self.1.clone()
-    }
 }
 
 impl<I, O, E, T> Parser<I, O, E> for Rc<T>
@@ -172,8 +154,4 @@ where
     fn parse(&self, input: I) -> ParseResult<I, O, E> {
         self.as_ref().parse(input)
     }
-
-    fn representation(&self) -> Representation {
-        self.as_ref().representation()
-    }
 }

src/parser/named_parser.rs

@@ -1,5 +1,5 @@
+use crate::parser::{ParseResult, Parser, ParserInput};
 use super::boxed_parser::BoxedParser;
-use crate::parser::{ParseResult, Parser, ParserInput, Representation};
 
 pub struct NamedParser<'a, I, O, E>
 where
@@ -26,10 +26,6 @@ where
 }
 
 impl<'a, I: ParserInput, O, E> Parser<I, O, E> for NamedParser<'a, I, O, E> {
-    fn representation(&self) -> Representation {
-        Representation::new("NOT IMPL'D")
-    }
-
     fn parse(&self, input: I) -> ParseResult<I, O, E> {
         self.inner_parser.parse(input)
     }

src/parser/parser_input.rs

@@ -1,11 +0,0 @@
-pub trait ParserInput: std::fmt::Debug {
-    type Output;
-    fn next_token() -> Self::Output;
-}
-
-impl ParserInput for &str {
-    type Output = ();
-    fn next_token() -> Self::Output {
-        ()
-    }
-}

src/parser/representation.rs

@@ -1,12 +0,0 @@
-
-
-#[derive(Debug, Clone)]
-pub struct Representation {
-    val: String
-}
-
-impl Representation {
-    pub fn new(from: &str) -> Self {
-        Self { val: from.to_string() }
-    }
-}

src/primitives/mod.rs

@@ -1,4 +1,4 @@
-use crate::parser::{ParseResult, Parser, ParserInput, Representation};
+use crate::parser::{ParseResult, Parser, ParserInput};
 
 pub fn literal_char(expected: char) -> impl Fn(&str) -> ParseResult<&str, char, &str> {
     move |input| match input.chars().next() {
@@ -7,13 +7,11 @@ pub fn literal_char(expected: char) -> impl Fn(&str) -> ParseResult<&str, char,
     }
 }
 
-pub fn literal<'a>(expected: &'static str) -> impl Parser<&'a str, &'a str, &'a str> {
+pub fn literal(expected: &'static str) -> impl Fn(&str) -> ParseResult<&str, &str, &str> {
-    println!("literal call expected: {}", expected);
+    move |input| match input.get(0..expected.len()) {
-    let p = move |input: &'a str| match input.get(0..expected.len()) {
         Some(next) if next == expected => Ok((expected, &input[expected.len()..])),
         _ => Err(input),
-    };
+    }
-    (p, Representation::new("yolo"))
 }
 
 pub fn any_char(input: &str) -> ParseResult<&str, char, &str> {
@@ -24,23 +22,15 @@ pub fn any_char(input: &str) -> ParseResult<&str, char, &str> {
 }
 
 pub fn one_of<'a>(items: &'static str) -> impl Parser<&'a str, &'a str, &'a str> {
-    let p = move |input: &'a str| {
+    move |input: &'a str| {
-        if let Some(ch) = input.chars().next() {
+        if let Some(ch) = input.chars().nth(0) {
             if items.contains(ch) {
                 let (first, rest) = input.split_at(1);
                 return Ok((first, rest));
             }
         }
         Err(input)
-    };
-
-    let mut s = String::new();
-    for ch in items.chars() {
-        s.push(ch);
-        s.push_str(" | ");
     }
-    let rep = Representation::new(&s);
-    (p, rep)
 }
 
 pub fn pred<P, F, I, O>(parser: P, pred_fn: F) -> impl Parser<I, O, I>
@@ -49,8 +39,7 @@ where
     P: Parser<I, O, I>,
     F: Fn(&O) -> bool,
 {
-    let orig_rep = parser.representation();
+    move |input| {
-    (move |input| {
         parser.parse(input).and_then(|(result, rest)| {
             if pred_fn(&result) {
                 Ok((result, rest))
@@ -58,7 +47,7 @@ where
                 Err(rest)
             }
         })
-    }, Representation::new(&format!("{:?} if <PREDICATE>", orig_rep)))
+    }
 }
 
 /// Parses a standard identifier in a programming language
@@ -71,7 +60,7 @@ pub fn identifier(input: &str) -> ParseResult<&str, String, &str> {
         _ => return Err(input),
     }
 
-    for next in chars {
+    while let Some(next) = chars.next() {
         if next.is_alphanumeric() {
             buf.push(next);
         } else {

tests/json_parser.rs

@@ -1,231 +0,0 @@
-use parser_combinator::choice::choice;
-use parser_combinator::combinators::repeated;
-use parser_combinator::primitives::{any_char, literal, literal_char, one_of, pred};
-use parser_combinator::sequence::seq;
-use parser_combinator::Parser;
-
-use proptest::prelude::*;
-
-proptest! {
-    #[test]
-    fn doesnt_crash(s in "\\PC*") {
-        let _output = json_object().parse(&s);
-    }
-
-    #[test]
-    fn parse_string(s in r#"[^"]+"#) {
-        let input = format!("\"{}\"", s);
-        let output = json_string().parse(&input).unwrap();
-        match output {
-            (JsonValue::Str(output_s), "") if output_s == s => (),
-            _ => panic!(),
-        }
-    }
-}
-
-#[test]
-fn test_parsing() {
-    let output = literal("a").parse("a yolo");
-    assert_eq!(output.unwrap(), ("a", " yolo"));
-}
-
-/*
-    * JSON BNF
-    * <JSON>     ::= <value>
-<value>    ::= <object> | <array> | <boolean> | <string> | <number> | <null>
-<array>    ::= "[" [<value>] {"," <value>}* "]"
-<object>   ::= "{" [<property>] {"," <property>}* "}"
-<property> ::= <string> ":" <value>
-*/
-#[derive(Debug, Clone, PartialEq)]
-enum JsonValue {
-    Null,
-    Bool(bool),
-    Str(String),
-    Num(f64),
-    Array(Vec<JsonValue>),
-    Object(Vec<(String, JsonValue)>),
-}
-
-trait JsonParser<'a, T>: Parser<&'a str, T, &'a str> {}
-impl<'a, T, P> JsonParser<'a, T> for P where P: Parser<&'a str, T, &'a str> {}
-
-fn json_null<'a>() -> impl JsonParser<'a, JsonValue> {
-    literal("null").to(JsonValue::Null)
-}
-fn json_bool<'a>() -> impl JsonParser<'a, JsonValue> {
-    choice((
-        literal("true").to(JsonValue::Bool(true)),
-        literal("false").to(JsonValue::Bool(false)),
-    ))
-}
-
-fn json_number<'a>() -> impl JsonParser<'a, JsonValue> {
-    let digit = || one_of("1234567890");
-    let digits = || repeated(digit()).at_least(1);
-
-    let json_number_inner = choice((
-        seq((digits(), literal(".").ignore_then(digits()).optional())).map(
-            |(mut digits, maybe_decimal)| {
-                if let Some(decimal_digits) = maybe_decimal {
-                    digits.push(".");
-                    digits.extend(decimal_digits.into_iter());
-                }
-                digits.into_iter().collect::<String>()
-            },
-        ),
-        literal(".").ignore_then(digits()).map(|decimal_digits| {
-            let mut d = vec!["."];
-            d.extend(decimal_digits.into_iter());
-            d.into_iter().collect::<String>()
-        }),
-    ))
-    .map(|digits| digits.parse::<f64>().unwrap());
-
-    literal("-")
-        .optional()
-        .then(json_number_inner)
-        .map(|(maybe_sign, mut val)| {
-            if maybe_sign.is_some() {
-                val *= -1.0;
-            }
-            JsonValue::Num(val)
-        })
-}
-
-fn json_string_raw<'a>() -> impl JsonParser<'a, String> {
-    seq((
-        literal_char('"'),
-        repeated(pred(any_char, |ch| *ch != '"')),
-        literal_char('"'),
-    ))
-    .map(|(_, s, _)| s.iter().cloned().collect::<String>())
-}
-
-fn json_string<'a>() -> impl JsonParser<'a, JsonValue> {
-    json_string_raw().map(JsonValue::Str)
-}
-
-fn whitespace<'a>() -> impl JsonParser<'a, ()> {
-    repeated(choice((
-        literal_char('\t'),
-        literal_char('\n'),
-        literal_char(' '),
-    )))
-    .to(())
-}
-
-fn json_array<'a>() -> impl JsonParser<'a, JsonValue> {
-    move |input| {
-        let val = json_value().surrounded_by(whitespace());
-
-        repeated(val)
-            .separated_by(literal(","), false)
-            .delimited(literal_char('['), literal_char(']'))
-            .map(JsonValue::Array)
-            .parse(input)
-    }
-}
-
-fn json_object<'a>() -> impl JsonParser<'a, JsonValue> {
-    move |input| {
-        let kv = json_string_raw()
-            .surrounded_by(whitespace())
-            .then_ignore(literal_char(':'))
-            .then(json_value().surrounded_by(whitespace()));
-
-        repeated(kv)
-            .separated_by(literal_char(','), false)
-            .delimited(literal_char('{'), literal_char('}'))
-            .map(JsonValue::Object)
-            .parse(input)
-    }
-}
-
-fn json_value<'a>() -> impl JsonParser<'a, JsonValue> {
-    choice((
-        json_null(),
-        json_bool(),
-        json_number(),
-        json_string(),
-        json_array(),
-        json_object(),
-    ))
-}
-
-#[test]
-fn parse_json_primitives() {
-    assert_eq!(
-        json_string().parse(r#""yolo swagg""#).unwrap(),
-        (JsonValue::Str("yolo swagg".into()), "")
-    );
-
-    assert_eq!(
-        json_number().parse("-383").unwrap().0,
-        JsonValue::Num(-383f64)
-    );
-    assert_eq!(
-        json_number().parse("-.383").unwrap().0,
-        JsonValue::Num(-0.383)
-    );
-    assert_eq!(
-        json_number().parse(".383").unwrap().0,
-        JsonValue::Num(0.383)
-    );
-    assert_eq!(
-        json_number().parse("-1.383").unwrap().0,
-        JsonValue::Num(-1.383)
-    );
-}
-
-#[test]
-fn parse_json_array() {
-    assert!(json_array().parse(r#"[ 4, 9, "ara",]"#).is_err());
-    assert_eq!(
-        json_array().parse("[[],[]]").unwrap().0,
-        JsonValue::Array(vec![JsonValue::Array(vec![]), JsonValue::Array(vec![])])
-    );
-    assert_eq!(
-        json_array().parse(r#"[  4,   9,   "foo"   ]"#).unwrap(),
-        (
-            JsonValue::Array(vec![
-                JsonValue::Num(4.),
-                JsonValue::Num(9.0),
-                JsonValue::Str("foo".to_string())
-            ]),
-            ""
-        )
-    );
-    assert_eq!(
-        json_array().parse(r#"[8,null,[],5],{}"#).unwrap(),
-        (
-            JsonValue::Array(vec![
-                JsonValue::Num(8.),
-                JsonValue::Null,
-                JsonValue::Array(vec![]),
-                JsonValue::Num(5.),
-            ]),
-            ",{}"
-        )
-    );
-    assert_eq!(json_value().parse("true"), Ok((JsonValue::Bool(true), "")));
-}
-
-#[test]
-fn parse_json_object() {
-    assert_eq!(
-        json_object().parse(r#"{ "a": 23}"#).unwrap().0,
-        JsonValue::Object(vec![("a".into(), JsonValue::Num(23.))])
-    );
-    assert_eq!(
-        json_object().parse(r#"{}"#).unwrap().0,
-        JsonValue::Object(vec![])
-    );
-}
-
-#[test]
-fn parse_json_document() {
-    let test_json = include_str!("joplin-cfg.json");
-    let parsed_json = json_object().parse(test_json);
-    assert!(parsed_json.is_ok());
-}