Add benchmarking code for json parser

Cargo.toml

@@ -5,9 +5,21 @@ edition = "2021"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
+[features]
+testutil = []
+
 [dependencies]
 arbitrary = "1.2.0"
 proptest = "1.0.0"
 
 [dev-dependencies]
+criterion = "0.4.0"
 rstest = "0.16.0"
+# see https://github.com/rust-lang/cargo/issues/2911#issuecomment-749580481
+parser-combinator = { path = ".", features = ["testutil"] }
+
+[[bench]]
+name = "json-benchmark"
+harness = false
+
+

benches/json-benchmark.rs

@@ -0,0 +1,14 @@
+use criterion::{black_box, criterion_group, criterion_main, Criterion};
+use parser_combinator::testutil::json_object;
+use parser_combinator::Parser;
+
+pub fn criterion_benchmark(c: &mut Criterion) {
+    let test_json = include_str!("../tests/joplin-cfg.json");
+
+    c.bench_function("parse_json", |b| {
+        b.iter(|| json_object().parse(black_box(test_json)))
+    });
+}
+
+criterion_group!(benches, criterion_benchmark);
+criterion_main!(benches);

src/lib.rs

@@ -4,4 +4,7 @@ mod parser;
 pub mod primitives;
 pub mod sequence;
 
+#[cfg(feature = "testutil")]
+pub mod testutil;
+
 pub use parser::{ParseResult, Parser, ParserInput, Representation};

src/testutil/mod.rs

@@ -0,0 +1,135 @@
+use crate::choice::choice;
+use crate::combinators::repeated;
+use crate::primitives::{any_char, literal, literal_char, one_of, pred};
+use crate::sequence::seq;
+use crate::Parser;
+
+/*
+    * JSON BNF
+    * <JSON>     ::= <value>
+<value>    ::= <object> | <array> | <boolean> | <string> | <number> | <null>
+<array>    ::= "[" [<value>] {"," <value>}* "]"
+<object>   ::= "{" [<property>] {"," <property>}* "}"
+<property> ::= <string> ":" <value>
+*/
+#[derive(Debug, Clone, PartialEq)]
+pub enum JsonValue {
+    Null,
+    Bool(bool),
+    Str(String),
+    Num(f64),
+    Array(Vec<JsonValue>),
+    Object(Vec<(String, JsonValue)>),
+}
+
+pub 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> {}
+
+pub fn json_null<'a>() -> impl JsonParser<'a, JsonValue> {
+    literal("null").to(JsonValue::Null)
+}
+
+pub fn json_bool<'a>() -> impl JsonParser<'a, JsonValue> {
+    choice((
+        literal("true").to(JsonValue::Bool(true)),
+        literal("false").to(JsonValue::Bool(false)),
+    ))
+}
+
+pub fn json_number<'a>() -> impl JsonParser<'a, JsonValue> {
+    fn digit<'a>() -> impl JsonParser<'a, &'a str> {
+        one_of("1234567890")
+    }
+
+    fn digits<'a>() -> impl JsonParser<'a, Vec<&'a str>> {
+        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)
+        })
+}
+
+pub 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>())
+}
+
+pub 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(())
+}
+
+pub 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)
+    }
+}
+
+pub 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)
+    }
+}
+
+pub fn json_value<'a>() -> impl JsonParser<'a, JsonValue> {
+    choice((
+        json_null(),
+        json_bool(),
+        json_number(),
+        json_string(),
+        json_array(),
+        json_object(),
+    ))
+}

tests/json_parser.rs

@@ -1,9 +1,8 @@
-use parser_combinator::choice::choice;
+use parser_combinator::primitives::literal;
-use parser_combinator::combinators::repeated;
+use parser_combinator::testutil::{
-use parser_combinator::primitives::{any_char, literal, literal_char, one_of, pred};
+    json_array, json_bool, json_null, json_number, json_object, json_string, JsonValue,
-use parser_combinator::sequence::seq;
+};
-use parser_combinator::Parser;
+use parser_combinator::{Parser, Representation};
-use parser_combinator::Representation;
 
 use proptest::prelude::*;
 
@@ -32,136 +31,6 @@ fn test_parsing() {
     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> {
-    fn digit<'a>() -> impl JsonParser<'a, &'a str> {
-        one_of("1234567890")
-    }
-
-    fn digits<'a>() -> impl JsonParser<'a, Vec<&'a str>> {
-        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!(