[Issue 13348] std.uni.byGrapheme is impure

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=13348

Steven Schveighoffer  changed:

   What|Removed |Added

 CC||schvei...@yahoo.com

--- Comment #5 from Steven Schveighoffer  ---
Something doesn't seem right here. byGrapheme is a template function, including
a templated struct. purity should be inferred everywhere here, no?

The code itself seems pretty simple, seems like all the impurity comes from
Grapheme and possibly decodeGrapheme.

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[Issue 13348] std.uni.byGrapheme is impure

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=13348

--- Comment #4 from hst...@quickfur.ath.cx ---
It's not a problem that byGrapheme is sometimes impure, but it should not be
the one introducing the impurity. I.e., if the incoming range is pure, then
byGrapheme ought to be also pure.

This can be enforced by not attributing byGrapheme directly, but using a pure
nothrow etc. unittest to ensure any impure/throwing/etc. code actually comes
from the incoming range, not from byGrapheme itself.

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[Issue 13348] std.uni.byGrapheme is impure

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=13348

Thayne  changed:

   What|Removed |Added

 CC||astrotha...@gmail.com

--- Comment #3 from Thayne  ---
I don't think byGrapheme can be pure in general, because, in general, the input
range used doesn't necessarily have pure input methods. For example the input
range could read from I/O.

The solution would probably be to add pure if and only if the front, popFront,
and empty methods of the inputRange are themselves pure.

I'm not sure what the best way to do that would be.

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[Issue 13348] std.uni.byGrapheme is impure

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=13348

hst...@quickfur.ath.cx changed:

   What|Removed |Added

   Severity|enhancement |blocker

--- Comment #2 from hst...@quickfur.ath.cx ---
Upgrade to blocker since the fix for issue #7054 is blocked by this.

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[Issue 13348] std.uni.byGrapheme is impure

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=13348

hst...@quickfur.ath.cx changed:

   What|Removed |Added

 Blocks||7054

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[Issue 13348] std.uni.byGrapheme is impure

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=13348

--- Comment #1 from hst...@quickfur.ath.cx ---
Ditto for graphemeStride.

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