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Use functions not closures

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This commit is contained in:
Greg Shuflin 2022-10-19 22:35:13 -07:00
parent e6ce2cf34d
commit 03ff159c95
1 changed files with 48 additions and 35 deletions
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83
src/lib.rs
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@ -41,17 +41,21 @@ mod tests {
Object(HashMap<String, JsonValue>), Object(HashMap<String, JsonValue>),
} }
#[test] trait JsonParser<'a, T>: Parser<&'a str, T, &'a str> {}
fn parse_json() { impl<'a, T, P> JsonParser<'a, T> for P where P: Parser<&'a str, T, &'a str> {}
let json_null = literal("null").to(JsonValue::Null);
let json_bool = choice(( 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("true").to(JsonValue::Bool(true)),
literal("false").to(JsonValue::Bool(false)), literal("false").to(JsonValue::Bool(false)),
)); ))
}
fn json_number() -> impl JsonParser<'static, JsonValue> {
let digit = || one_of("1234567890"); let digit = || one_of("1234567890");
assert_eq!(digit().parse("3"), Ok(("3", "")));
let digits = || repeated(digit()).at_least(1); let digits = || repeated(digit()).at_least(1);
let json_number_inner = choice(( let json_number_inner = choice((
@ -72,40 +76,49 @@ mod tests {
)) ))
.map(|digits| digits.parse::<f64>().unwrap()); .map(|digits| digits.parse::<f64>().unwrap());
let json_number = literal("-")
literal("-") .optional()
.optional() .then(json_number_inner)
.then(json_number_inner) .map(|(maybe_sign, mut val)| {
.map(|(maybe_sign, mut val)| { if maybe_sign.is_some() {
if maybe_sign.is_some() { val *= -1.0;
val *= -1.0; }
} JsonValue::Num(val)
JsonValue::Num(val) })
}); }
assert_eq!( fn json_string<'a>() -> impl JsonParser<'a, JsonValue> {
json_number.parse("-383").unwrap().0, seq((
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)
);
let json_string = seq((
literal_char('"'), literal_char('"'),
pred(any_char, |ch| *ch != '"'), pred(any_char, |ch| *ch != '"'),
literal_char('"'), literal_char('"'),
)) ))
.map(|(_, s, _)| JsonValue::Str(s.to_string())); .map(|(_, s, _)| JsonValue::Str(s.to_string()))
}
let json_value = choice((json_null, json_bool, json_number, json_string)); fn json_value() -> impl JsonParser<'static, JsonValue> {
choice((json_null(), json_bool(), json_number(), json_string()))
}
assert_eq!(json_value.parse("true"), Ok((JsonValue::Bool(true), ""))); #[test]
fn parse_json() {
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)
);
assert_eq!(json_value().parse("true"), Ok((JsonValue::Bool(true), "")));
} }
} }