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Improvements to std.uni.sicmp and std.uni.icmp #4256

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DmitryOlshansky merged 2 commits into from
Apr 29, 2016
Merged

Improvements to std.uni.sicmp and std.uni.icmp #4256

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7922bc8
Fix Issue 15964: The template constraints for std.uni.sicmp are too p…
JackStouffer Apr 28, 2016
afd54b5
Improve docs for icmp
JackStouffer Apr 28, 2016
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38 changes: 30 additions & 8 deletions std/uni.d
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Original file line number Diff line number Diff line change
Expand Up @@ -6930,8 +6930,8 @@ unittest
than $(LREF icmp). However keep in mind the warning below.)

Params:
str1 = a string or a $(D ForwardRange) of $(D dchar)s
str2 = a string or a $(D ForwardRange) of $(D dchar)s
str1 = a string
str2 = a string

Returns:
An $(D int) that is 0 if the strings match,
Expand All @@ -6947,17 +6947,16 @@ unittest
$(LREF icmp)
$(XREF_PACK algorithm,comparison,cmp)
+/
int sicmp(S1, S2)(S1 str1, S2 str2)
if (isForwardRange!S1 && is(Unqual!(ElementType!S1) == dchar)
&& isForwardRange!S2 && is(Unqual!(ElementType!S2) == dchar))
int sicmp(S1, S2)(S1 str1, S2 str2) if (isSomeString!S1 && isSomeString!S2)
{
alias sTable = simpleCaseTable;
import std.utf : decode;

size_t ridx=0;
foreach (dchar lhs; str1)
{
if (ridx == str2.length)
return 1;
import std.utf : decode;
dchar rhs = decode(str2, ridx);
int diff = lhs - rhs;
if (!diff)
Expand Down Expand Up @@ -6991,7 +6990,8 @@ int sicmp(S1, S2)(S1 str1, S2 str2)
}

///
unittest{
unittest
{
assert(sicmp("Август", "авгусТ") == 0);
// Greek also works as long as there is no 1:M mapping in sight
assert(sicmp("ΌΎ", "όύ") == 0);
Expand Down Expand Up @@ -7060,6 +7060,15 @@ private int fullCasedCmp(Range)(dchar lhs, dchar rhs, ref Range rtail)
The cost of $(D icmp) being pedantically correct is
slightly worse performance.
)

Returns:
An $(D int) that is 0 if the strings match,
<0 if $(D str1) is lexicographically "less" than $(D str2),
>0 if $(D str1) is lexicographically "greater" than $(D str2)

See_Also:
$(LREF sicmp)
$(XREF_PACK algorithm,comparison,cmp)
+/
int icmp(S1, S2)(S1 str1, S2 str2)
if (isForwardRange!S1 && is(Unqual!(ElementType!S1) == dchar)
Expand Down Expand Up @@ -7094,11 +7103,24 @@ int icmp(S1, S2)(S1 str1, S2 str2)
}

///
unittest{
unittest
{
assert(icmp("Rußland", "Russland") == 0);
assert(icmp("ᾩ -> \u1F70\u03B9", "\u1F61\u03B9 -> ᾲ") == 0);
}

/**
* By using $(XREF utf, byUTF) and its aliases, GC allocations via auto-decoding
* and thrown exceptions can be avoided, making `icmp` `@safe @nogc nothrow pure`.
*/
@safe @nogc nothrow pure unittest
{
import std.utf : byDchar;

assert(icmp("Rußland".byDchar, "Russland".byDchar) == 0);
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@wilzbach wilzbach Apr 29, 2016

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Wait what???
In German (my mother tongue) this is not guaranteed to be correct. From Wikipedia:

Thus it helps to distinguish words like Buße (long vowel) 'penance, fine' and Busse (short vowel) 'buses'.

https://en.m.wikipedia.org/wiki/%C3%9F

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@DmitryOlshansky DmitryOlshansky Apr 29, 2016

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This is caseless comparison and follows rules of Unicode

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@wilzbach wilzbach Apr 29, 2016

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This is caseless comparison and follows rules of Unicode

Oh sorry. Overlooked from my phone :/

assert(icmp("ᾩ -> \u1F70\u03B9".byDchar, "\u1F61\u03B9 -> ᾲ".byDchar) == 0);
}

// overloads for the most common cases to reduce compile time
@safe pure /*TODO nothrow*/
{
Expand Down