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Provide groupBy and groupByTo with keySelector and valueTransform.

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Rename parameters of groupBy, add type parameter for MutableMap to groupByTo.
This commit is contained in:
Ilya Gorbunov
2016-01-25 21:15:56 +03:00
parent 0eaaee8202
commit 7703252239
6 changed files with 565 additions and 112 deletions
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libraries/tools/kotlin-stdlib-gen/src/templates/Mapping.kt
+74 -9
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@@ -277,33 +277,98 @@ fun mapping(): List<GenericFunction> {
}
}
templates add f("groupBy(selector: (T) -> K)") {
templates add f("groupBy(keySelector: (T) -> K)") {
inline(true)
include(CharSequences)
doc { f -> "Returns a map of the ${f.element.pluralize()} in original ${f.collection} grouped by the key returned by the given [selector] function." }
doc { f ->
"""
Groups ${f.element.pluralize()} of the original ${f.collection} by the key returned by the given [keySelector] function
applied to each ${f.element} and returns a map where each group key is associated with a list of corresponding ${f.element.pluralize()}.
@sample test.collections.CollectionTest.groupBy
"""
}
typeParam("K")
returns("Map<K, List<T>>")
body { "return groupByTo(LinkedHashMap<K, MutableList<T>>(), selector)" }
body { "return groupByTo(LinkedHashMap<K, MutableList<T>>(), keySelector)" }
}
templates add f("groupByTo(map: MutableMap<K, MutableList<T>>, selector: (T) -> K)") {
templates add f("groupByTo(destination: M, keySelector: (T) -> K)") {
inline(true)
include(CharSequences)
typeParam("K")
doc { f -> "Appends ${f.element.pluralize()} from original ${f.collection} grouped by the key returned by the given [selector] function to the given [map]." }
returns("Map<K, MutableList<T>>")
typeParam("M : MutableMap<in K, MutableList<T>>")
doc { f ->
"""
Groups ${f.element.pluralize()} of the original ${f.collection} by the key returned by the given [keySelector] function
applied to each ${f.element} and puts to the [destination] map each group key associated with a list of corresponding ${f.element.pluralize()}.
@return The [destination] map.
@sample test.collections.CollectionTest.groupBy
"""
}
returns("M")
body {
"""
for (element in this) {
val key = selector(element)
val list = map.getOrPut(key) { ArrayList<T>() }
val key = keySelector(element)
val list = destination.getOrPut(key) { ArrayList<T>() }
list.add(element)
}
return map
return destination
"""
}
}
templates add f("groupBy(keySelector: (T) -> K, valueTransform: (T) -> V)") {
inline(true)
include(CharSequences)
doc { f ->
"""
Groups values returned by the [valueTransform] function applied to each ${f.element} of the original ${f.collection}
by the key returned by the given [keySelector] function applied to the ${f.element}
and returns a map where each group key is associated with a list of corresponding values.
@sample test.collections.CollectionTest.groupByKeysAndValues
"""
}
typeParam("K")
typeParam("V")
returns("Map<K, List<V>>")
body { "return groupByTo(LinkedHashMap<K, MutableList<V>>(), keySelector, valueTransform)" }
}
templates add f("groupByTo(destination: M, keySelector: (T) -> K, valueTransform: (T) -> V)") {
inline(true)
include(CharSequences)
typeParam("K")
typeParam("V")
typeParam("M : MutableMap<in K, MutableList<V>>")
doc { f ->
"""
Groups values returned by the [valueTransform] function applied to each ${f.element} of the original ${f.collection}
by the key returned by the given [keySelector] function applied to the ${f.element}
and puts to the [destination] map each group key associated with a list of corresponding values.
@return The [destination] map.
@sample test.collections.CollectionTest.groupByKeysAndValues
"""
}
returns("M")
body {
"""
for (element in this) {
val key = keySelector(element)
val list = destination.getOrPut(key) { ArrayList<V>() }
list.add(valueTransform(element))
}
return destination
"""
}
}
return templates
}