More JSON

src/lib.rs

@@ -12,7 +12,8 @@ pub use parser::{ParseResult, Parser};
 mod tests {
     use super::*;
     use crate::choice::choice;
-    use crate::primitives::literal;
+    use crate::primitives::{any_char, literal, literal_char, pred};
+    use crate::sequence::seq;
     use std::collections::HashMap;
 
     #[test]
@@ -42,10 +43,19 @@ mod tests {
     #[test]
     fn parse_json() {
         let json_null = literal("null").to(JsonValue::Null);
-        let json_true = literal("true").to(JsonValue::Bool(true));
-        let json_false = literal("false").to(JsonValue::Bool(false));
+        let json_bool = choice((
+            literal("true").to(JsonValue::Bool(true)),
+            literal("false").to(JsonValue::Bool(false)),
+        ));
 
-        let json_value = choice((json_null, json_true, json_false));
+        let json_string = seq((
+            literal_char('"'),
+            pred(any_char, |ch| *ch != '"'),
+            literal_char('"'),
+        ))
+        .map(|(_, s, _)| JsonValue::Str(s.to_string()));
+
+        let json_value = choice((json_null, json_bool, json_string));
 
         assert_eq!(json_value.parse("true"), Ok((JsonValue::Bool(true), "")));
     }

src/primitives.rs

@@ -1,5 +1,12 @@
 use crate::parser::{ParseResult, Parser};
 
+pub fn literal_char(expected: char) -> impl Fn(&str) -> ParseResult<&str, char, &str> {
+    move |input| match input.chars().next() {
+        Some(ch) if ch == expected => Ok((expected, &input[ch.len_utf8()..])),
+        _ => Err(input),
+    }
+}
+
 pub fn literal(expected: &'static str) -> impl Fn(&str) -> ParseResult<&str, &str, &str> {
     move |input| match input.get(0..expected.len()) {
         Some(next) if next == expected => Ok((expected, &input[expected.len()..])),