diff options
Diffstat (limited to 'common/predicate')
| -rw-r--r-- | common/predicate/predicate.go | 72 | ||||
| -rw-r--r-- | common/predicate/predicate_test.go | 83 |
2 files changed, 155 insertions, 0 deletions
diff --git a/common/predicate/predicate.go b/common/predicate/predicate.go new file mode 100644 index 000000000..f9cb1bb2b --- /dev/null +++ b/common/predicate/predicate.go @@ -0,0 +1,72 @@ +// Copyright 2024 The Hugo Authors. All rights reserved. +// +// 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. + +package predicate + +// P is a predicate function that tests whether a value of type T satisfies some condition. +type P[T any] func(T) bool + +// And returns a predicate that is a short-circuiting logical AND of this and the given predicates. +func (p P[T]) And(ps ...P[T]) P[T] { + return func(v T) bool { + for _, pp := range ps { + if !pp(v) { + return false + } + } + return p(v) + } +} + +// Or returns a predicate that is a short-circuiting logical OR of this and the given predicates. +func (p P[T]) Or(ps ...P[T]) P[T] { + return func(v T) bool { + for _, pp := range ps { + if pp(v) { + return true + } + } + return p(v) + } +} + +// Negate returns a predicate that is a logical negation of this predicate. +func (p P[T]) Negate() P[T] { + return func(v T) bool { + return !p(v) + } +} + +// Filter returns a new slice holding only the elements of s that satisfy p. +// Filter modifies the contents of the slice s and returns the modified slice, which may have a smaller length. +func (p P[T]) Filter(s []T) []T { + var n int + for _, v := range s { + if p(v) { + s[n] = v + n++ + } + } + return s[:n] +} + +// FilterCopy returns a new slice holding only the elements of s that satisfy p. +func (p P[T]) FilterCopy(s []T) []T { + var result []T + for _, v := range s { + if p(v) { + result = append(result, v) + } + } + return result +} diff --git a/common/predicate/predicate_test.go b/common/predicate/predicate_test.go new file mode 100644 index 000000000..1e1ec004b --- /dev/null +++ b/common/predicate/predicate_test.go @@ -0,0 +1,83 @@ +// Copyright 2024 The Hugo Authors. All rights reserved. +// +// 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. + +package predicate_test + +import ( + "testing" + + qt "github.com/frankban/quicktest" + "github.com/gohugoio/hugo/common/predicate" +) + +func TestAdd(t *testing.T) { + c := qt.New(t) + + var p predicate.P[int] = intP1 + + c.Assert(p(1), qt.IsTrue) + c.Assert(p(2), qt.IsFalse) + + neg := p.Negate() + c.Assert(neg(1), qt.IsFalse) + c.Assert(neg(2), qt.IsTrue) + + and := p.And(intP2) + c.Assert(and(1), qt.IsFalse) + c.Assert(and(2), qt.IsFalse) + c.Assert(and(10), qt.IsTrue) + + or := p.Or(intP2) + c.Assert(or(1), qt.IsTrue) + c.Assert(or(2), qt.IsTrue) + c.Assert(or(10), qt.IsTrue) + c.Assert(or(11), qt.IsFalse) +} + +func TestFilter(t *testing.T) { + c := qt.New(t) + + var p predicate.P[int] = intP1 + p = p.Or(intP2) + + ints := []int{1, 2, 3, 4, 1, 6, 7, 8, 2} + + c.Assert(p.Filter(ints), qt.DeepEquals, []int{1, 2, 1, 2}) + c.Assert(ints, qt.DeepEquals, []int{1, 2, 1, 2, 1, 6, 7, 8, 2}) +} + +func TestFilterCopy(t *testing.T) { + c := qt.New(t) + + var p predicate.P[int] = intP1 + p = p.Or(intP2) + + ints := []int{1, 2, 3, 4, 1, 6, 7, 8, 2} + + c.Assert(p.FilterCopy(ints), qt.DeepEquals, []int{1, 2, 1, 2}) + c.Assert(ints, qt.DeepEquals, []int{1, 2, 3, 4, 1, 6, 7, 8, 2}) +} + +var intP1 = func(i int) bool { + if i == 10 { + return true + } + return i == 1 +} + +var intP2 = func(i int) bool { + if i == 10 { + return true + } + return i == 2 +} |