42 lines
1.8 KiB
Rust
42 lines
1.8 KiB
Rust
// Copyright 2016 Mozilla
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//
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// Licensed under the Apache License, Version 2.0 (the "License"); you may not use
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// this file except in compliance with the License. You may obtain a copy of the
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// License at http://www.apache.org/licenses/LICENSE-2.0
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// Unless required by applicable law or agreed to in writing, software distributed
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// under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
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// CONDITIONS OF ANY KIND, either express or implied. See the License for the
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// specific language governing permissions and limitations under the License.
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extern crate combine;
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use combine::ParseResult;
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use combine::combinator::{Expected, FnParser};
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/// A type definition for a function parser that either parses an `O` from an input stream of type
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/// `I`, or fails with an "expected" failure.
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/// See <https://docs.rs/combine/2.2.1/combine/trait.Parser.html#method.expected> for more
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/// illumination.
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/// Nothing about this is specific to the result type of the parser.
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pub type ResultParser<O, I> = Expected<FnParser<I, fn(I) -> ParseResult<O, I>>>;
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/// `assert_parses_to!` simplifies some of the boilerplate around running a
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/// parser function against input and expecting a certain result.
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#[macro_export]
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macro_rules! assert_parses_to {
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( $parser: path, $input: expr, $expected: expr ) => {{
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let mut par = $parser();
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let result = par.parse(&$input[..]);
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assert_eq!(result, Ok(($expected, &[][..])));
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}}
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}
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/// `satisfy_unwrap!` makes it a little easier to implement a `satisfy_map`
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/// body that matches a particular `Value` enum case, otherwise returning `None`.
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#[macro_export]
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macro_rules! satisfy_unwrap {
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( $cas: path, $var: ident, $body: block ) => {
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satisfy_map(|x: edn::Value| if let $cas($var) = x $body else { None })
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}
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}
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