textparse

A Rust library to declaratively implement parsers that are based on Packrat Parsing.

Examples

The following code implements a parser for a JSON subset format: ```rust use textparse::{ components::{AnyChar, Char, Digit, Eos, Items, NonEmpty, Not, Str, While, Whitespace}, Parse, Parser, Position, Span, };

[derive(Clone, Span, Parse)]

struct JsonValue(WithoutWhitespaces);

[derive(Clone, Span, Parse)]

[parse(name = "a JSON value")]

enum JsonValueInner { Null(JsonNull), String(JsonString), Number(JsonNumber), Array(JsonArray), Object(JsonObject), }

[derive(Clone, Span, Parse)]

struct JsonNull(Str<'n', 'u', 'l', 'l'>);

[derive(Clone, Span, Parse)]

[parse(name = "a JSON string")]

struct JsonString(Char<'"'>, While<(Not>, AnyChar)>, Char<'"'>);

[derive(Clone, Span, Parse)]

[parse(name = "a JSON number")]

struct JsonNumber(NonEmpty>);

[derive(Clone, Span, Parse)]

[parse(name = "a JSON array")]

struct JsonArray(Char<'['>, Csv, Char<']'>);

[derive(Clone, Span, Parse)]

[parse(name = "a JSON object")]

struct JsonObject(Char<'{'>, Csv, Char<'}'>);

[derive(Clone, Span, Parse)]

struct JsonObjectItem(WithoutWhitespaces, Char<':'>, JsonValue);

[derive(Clone, Span, Parse)]

struct Csv(Items>);

[derive(Clone, Span, Parse)]

struct WithoutWhitespaces(While, T, While); ```

You can run the above parser via examples/checkjson.rs as follows: ```console $ echo '["foo",null,{"key": "value"}, 123]' | cargo run --example checkjson OK: the input string is a JSON text.

$ echo '["foo" null]' | cargo run --example check_json Error: expected one of ',', or ']' --> :1:8 | 1 | ["foo" null] | ^ expected one of ',', or ']' ```