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Diffstat (limited to 'src/matchers/tuple_matcher.rs')
| -rw-r--r-- | src/matchers/tuple_matcher.rs | 207 |
1 files changed, 207 insertions, 0 deletions
diff --git a/src/matchers/tuple_matcher.rs b/src/matchers/tuple_matcher.rs new file mode 100644 index 0000000..a2e325b --- /dev/null +++ b/src/matchers/tuple_matcher.rs @@ -0,0 +1,207 @@ +// Copyright 2022 Google LLC +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +// There are no visible documentation elements in this module; the declarative +// macro is documented at the top level. +#![doc(hidden)] + +/// Functions for use only by the declarative macros in this module. +/// +/// **For internal use only. API stablility is not guaranteed!** +#[doc(hidden)] +pub mod internal { + use crate::matcher::{Matcher, MatcherResult}; + use std::fmt::{Debug, Write}; + + /// Replaces the first expression with the second at compile time. + /// + /// This is used below in repetition sequences where the output must only + /// include the same expression repeated the same number of times as the + /// macro input. + /// + /// **For internal use only. API stablility is not guaranteed!** + #[doc(hidden)] + macro_rules! replace_expr { + ($_ignored:tt, $replacement:expr) => { + $replacement + }; + } + + // This implementation is provided for completeness, but is completely trivial. + // The only actual value which can be supplied is (), which must match. + impl Matcher for () { + type ActualT = (); + + fn matches(&self, _: &Self::ActualT) -> MatcherResult { + MatcherResult::Match + } + + fn describe(&self, matcher_result: MatcherResult) -> String { + match matcher_result { + MatcherResult::Match => "is the empty tuple".into(), + MatcherResult::NoMatch => "is not the empty tuple".into(), + } + } + } + + /// Generates a tuple matcher for tuples of a specific length. + /// + /// **For internal use only. API stablility is not guaranteed!** + #[doc(hidden)] + macro_rules! tuple_matcher_n { + ($([$field_number:tt, $matcher_type:ident, $field_type:ident]),*) => { + impl<$($field_type: Debug, $matcher_type: Matcher<ActualT = $field_type>),*> + Matcher for ($($matcher_type,)*) + { + type ActualT = ($($field_type,)*); + + fn matches(&self, actual: &($($field_type,)*)) -> MatcherResult { + $(match self.$field_number.matches(&actual.$field_number) { + MatcherResult::Match => {}, + MatcherResult::NoMatch => { + return MatcherResult::NoMatch; + } + })* + MatcherResult::Match + } + + fn explain_match(&self, actual: &($($field_type,)*)) -> String { + let mut explanation = format!("which {}", self.describe(self.matches(actual))); + $(match self.$field_number.matches(&actual.$field_number) { + MatcherResult::Match => {}, + MatcherResult::NoMatch => { + writeln!( + &mut explanation, + concat!("Element #", $field_number, " is {:?}, {}"), + actual.$field_number, + self.$field_number.explain_match(&actual.$field_number) + ).unwrap(); + } + })* + (explanation) + } + + fn describe(&self, matcher_result: MatcherResult) -> String { + match matcher_result { + MatcherResult::Match => { + format!( + concat!( + "is a tuple whose values respectively match:\n", + $(replace_expr!($field_number, " {},\n")),* + ), + $(self.$field_number.describe(matcher_result)),* + ) + } + MatcherResult::NoMatch => { + format!( + concat!( + "is a tuple whose values do not respectively match:\n", + $(replace_expr!($field_number, " {},\n")),* + ), + $(self.$field_number.describe(MatcherResult::Match)),* + ) + } + } + } + } + }; + } + + tuple_matcher_n!([0, I0, T0]); + + tuple_matcher_n!([0, I0, T0], [1, I1, T1]); + + tuple_matcher_n!([0, I0, T0], [1, I1, T1], [2, I2, T2]); + + tuple_matcher_n!([0, I0, T0], [1, I1, T1], [2, I2, T2], [3, I3, T3]); + + tuple_matcher_n!([0, I0, T0], [1, I1, T1], [2, I2, T2], [3, I3, T3], [4, I4, T4]); + + tuple_matcher_n!([0, I0, T0], [1, I1, T1], [2, I2, T2], [3, I3, T3], [4, I4, T4], [5, I5, T5]); + + tuple_matcher_n!( + [0, I0, T0], + [1, I1, T1], + [2, I2, T2], + [3, I3, T3], + [4, I4, T4], + [5, I5, T5], + [6, I6, T6] + ); + + tuple_matcher_n!( + [0, I0, T0], + [1, I1, T1], + [2, I2, T2], + [3, I3, T3], + [4, I4, T4], + [5, I5, T5], + [6, I6, T6], + [7, I7, T7] + ); + + tuple_matcher_n!( + [0, I0, T0], + [1, I1, T1], + [2, I2, T2], + [3, I3, T3], + [4, I4, T4], + [5, I5, T5], + [6, I6, T6], + [7, I7, T7], + [8, I8, T8] + ); + + tuple_matcher_n!( + [0, I0, T0], + [1, I1, T1], + [2, I2, T2], + [3, I3, T3], + [4, I4, T4], + [5, I5, T5], + [6, I6, T6], + [7, I7, T7], + [8, I8, T8], + [9, I9, T9] + ); + + tuple_matcher_n!( + [0, I0, T0], + [1, I1, T1], + [2, I2, T2], + [3, I3, T3], + [4, I4, T4], + [5, I5, T5], + [6, I6, T6], + [7, I7, T7], + [8, I8, T8], + [9, I9, T9], + [10, I10, T10] + ); + + tuple_matcher_n!( + [0, I0, T0], + [1, I1, T1], + [2, I2, T2], + [3, I3, T3], + [4, I4, T4], + [5, I5, T5], + [6, I6, T6], + [7, I7, T7], + [8, I8, T8], + [9, I9, T9], + [10, I10, T10], + [11, I11, T11] + ); +} |