On 02/22/2017 12:02 PM, ag0aep6g wrote:
> On Wednesday, 22 February 2017 at 19:26:15 UTC, berni wrote:
>> In my program, I read a postscript file. Normal postscript files
>> should only be composed of ascii characters, but one never knows what
>> users give us. Therefore I'd like to make sure that the string the
>> program read is only made up of ascii characters. This simplifies the
>> code thereafter, because I then can assume, that codeunit==codepoint.
>> Is there a simple way to do so?
>>
>> Here a sketch of my function:
>>
>>> void foo(string postscript)
>>> {
>>> // throw Exception, if postscript is not all ascii
>>> // other stuff, assuming codeunit=codepoint
>>> }
>
> Making full use of the standard library:
>
> ----
> import std.algorithm: all;
> import std.ascii: isASCII;
> import std.exception: enforce;
>
> enforce(postscript.all!isASCII);
> ----
>
> That checks on the code point level (because strings are ranges of
> dchars). If you want to be clever, you can avoid decoding and check on
> the code unit level:
>
> ----
> /* other imports as above */
> import std.utf: byCodeUnit;
>
> enforce(postscript.byCodeUnit.all!isASCII);
> ----
>
> Or you can do it manually, avoiding all those imports:
>
> ----
> foreach (char c; postscript) if (c > 0x7F) throw new Exception("not
> ASCII");
> ----
One more:
bool isAscii(string s) {
import std.string : representation;
import std.algorithm : canFind;
return !s.representation.canFind!(c => c >= 0x80);
}
unittest {
assert(isAscii("hello world"));
assert(!isAscii("hellö wörld"));
}
Ali
