malachi 0.9.8

A domain specific pattern matching language made for defining bot commands.
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58

// SPDX-License-Identifier: Apache-2.0
// Copyright 2024 Taylan Gökkaya

// This file is licensed under the terms of Apache-2.0 License.

use super::{
	prelude::*,
	string::parse_string,
	Filter,
};

fn parse_keyword(input: &str) -> IResult<&str, &str> {
	context(
		"filter name",
		recognize(pair(alpha1, many0(alt((alphanumeric1, tag("-")))))),
	)(input)
}

pub fn parse_regex(input: &str) -> IResult<&str, String> {
	let upto = is_not("/\\");
	let parse_fragment = alt((
		upto,
		value("/", tag("\\/")),
		recognize(pair(tag("\\"), take(1_usize))),
	));

	delimited(
		tag("/"),
		context(
			"empty regex",
			fold_many1(parse_fragment, String::new, |buf, s| buf + s),
		),
		tag("/"),
	)(input)
}

pub fn parse_filter(input: &str) -> IResult<&str, Filter<'_>> {
	// The syntax for filters is exactly like a function call in rust.
	// Arguments  are comma separated quoted strings.
	// A string literal can be used as a shorthand for `eq("...")`.
	let args = wrap_space0(list0(parse_string, ','));
	let args = delimited(char('('), args, char(')'));

	let normal = map(pair(parse_keyword, args), |(name, args)| Filter {
		name,
		args,
	});
	let short = map(parse_string, |s| Filter {
		name: "eq",
		args: vec![s],
	});
	let reg = map(parse_regex, |s| Filter {
		name: "regex",
		args: vec![s],
	});

	alt((normal, short, reg))(input)
}