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Fix issue #21702 - avoid quadratic template expansion in constraints of multiple search term versions of std.algorithm.searching.startsWith & endsWith

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Nathan Sashihara 2021-03-12 07:58:28 -08:00 • committed by The Dlang Bot
parent 748002fe86
commit 6d9a508baf
1 changed files with 10 additions and 13 deletions
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23
std/algorithm/searching.d
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@ -103,6 +103,7 @@ T2=$(TR $(TDNW $(LREF $1)) $(TD $+))
module std.algorithm.searching;
import std.functional : unaryFun, binaryFun;
import std.meta : allSatisfy;
import std.range.primitives;
import std.traits;
import std.typecons : Tuple, Flag, Yes, No, tuple;
@ -769,9 +770,7 @@ ptrdiff_t countUntil(alias pred = "a == b", R, Rs...)(R haystack, Rs needles)
if (isForwardRange!R
&& Rs.length > 0
&& isForwardRange!(Rs[0]) == isInputRange!(Rs[0])
&& is(typeof(startsWith!pred(haystack, needles[0])))
&& (Rs.length == 1
|| is(typeof(countUntil!pred(haystack, needles[1 .. $])))))
&& allSatisfy!(canTestStartsWith!(pred, R), Rs))
{
typeof(return) result;
@ -1027,8 +1026,7 @@ In the case when no needle parameters are given, return `true` iff back of
*/
uint endsWith(alias pred = "a == b", Range, Needles...)(Range doesThisEnd, Needles withOneOfThese)
if (isBidirectionalRange!Range && Needles.length > 1 &&
is(typeof(.endsWith!pred(doesThisEnd, withOneOfThese[0])) : bool) &&
is(typeof(.endsWith!pred(doesThisEnd, withOneOfThese[1 .. $])) : uint))
allSatisfy!(canTestStartsWith!(pred, Range), Needles))
{
alias haystack = doesThisEnd;
alias needles = withOneOfThese;
@ -2499,8 +2497,6 @@ $(REF among, std,algorithm,comparison) for checking a value against multiple pos
+/
template canFind(alias pred="a == b")
{
import std.meta : allSatisfy;
/++
Returns `true` if and only if any value `v` found in the
input range `range` satisfies the predicate `pred`.
@ -4217,8 +4213,6 @@ Params:
*/
template skipOver(alias pred = (a, b) => a == b)
{
import std.meta : allSatisfy;
enum bool isPredComparable(T) = ifTestable!(T, binaryFun!pred);
/**
@ -4607,11 +4601,8 @@ In the case when no needle parameters are given, return `true` iff front of
*/
uint startsWith(alias pred = (a, b) => a == b, Range, Needles...)(Range doesThisStart, Needles withOneOfThese)
if (isInputRange!Range && Needles.length > 1 &&
is(typeof(.startsWith!pred(doesThisStart, withOneOfThese[0])) : bool ) &&
is(typeof(.startsWith!pred(doesThisStart, withOneOfThese[1 .. $])) : uint))
allSatisfy!(canTestStartsWith!(pred, Range), Needles))
{
import std.meta : allSatisfy;
template checkType(T)
{
enum checkType = is(immutable ElementEncodingType!Range == immutable T);
@ -4933,6 +4924,12 @@ if (isInputRange!R &&
}}
}
private template canTestStartsWith(alias pred, Haystack)
{
enum bool canTestStartsWith(Needle) = is(typeof(
(ref Haystack h, ref Needle n) => startsWith!pred(h, n)));
}
/* (Not yet documented.)
Consume all elements from `r` that are equal to one of the elements
`es`.