136 lines
3.7 KiB
Rust
136 lines
3.7 KiB
Rust
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(),
|
|
))
|
|
}
|