Comments on Programming and Debugging (in my Underhøøsen): Strumming Strings In the D Chord

Anonymous, here's the crux of the issue: in D, a s...

2009-03-22T12:30:00.000-07:00

Anonymous, here's the crux of the issue: in D, a string is an array; arrays and slices can also be used interchangeably.

In .net System.String, System.Array and the generic System.ArraySegment are three different types. So, if I want to take a slice of a string in D/.NET (assuming strings implemented as System.String) I would need two conversions: from string to array of System.Char, and from that to ArraySegment.

Consider this (contrived, I agree) example:
void foo(string a)
{
cast(char)(a [0]) = 'W';
}
void main()
{
string s = "hello world";
foo(s[6..$]);
//...
assert(s[6] == 'W');
}
The generated code to make this work is quite complicated and very inefficient (again, assuming string === System.String). With strings implemented as unsigned int8[] arrays generating the code is quite straight forward.

I think that I found a good compromise so far... We'll see how well this works "in the field" once I release it :)

Do you mean, programmer could carefully count non-...

2009-03-22T01:54:00.000-07:00

Do you mean, programmer could carefully count non-english utf8 char lengths for slices? I doubt someone did this. Isn't it better to change specs a little than coping with full compatibility? Do you plan full compatibility? I think, some features should change, since .net way is quite different from D way. Well... if you hope D.net will outperform other .net dialects introducins D way into .net... hmm... it will be interesting.

Hi Anonymous, I tried using System.String by defau...

2009-03-18T10:14:00.000-07:00

Hi Anonymous, I tried using System.String by default like you are suggesting but I found it very difficult to get string slices to work right.

I think, you should use native System.String more ...

2009-03-18T02:54:00.000-07:00

I think, you should use native System.String more aggressively and convert strings to utf8 when and only when it's really needed, e.g. on casting to other pointer types, pinvoke etc.