I'm about ready to pull my hair out!!!
I'm trying to write a template that will split a string based on a character:

> char[][] foo = SplitString!("hello|world|this|is|a|test",'|'); // foo == ["hello","world","this","is","a","test"];

I keep getting an error about this being non-const:

> null[0..0] ~ "hello" ~ "world" ~ "this" ~ "is" ~ "a" ~ "test"

I'm doing something like this:

>template SplitString(char[] string, char c)
>{
>	static if(string == "")
>		char[][] SplitString = (char[][]).init;
>	else
>		char[][] SplitString = SplitString!(BeforLast!(string,c),c) ~ AfterLast!(string,c);
>}

Any ideas??



Better yet would be a template that evaluates to a tuple

>template SplitString(char[] string, char c, V...)
>{
>	static if(string == "")
>		auto SplitString = V;
>	else
>		auto SplitString = SplitString!(BeforLast!(string,c),c, V, AfterLast!(string,c));
>}

that would allow this:

>void foo(char[] string)
>{
>	// static foreach
>	foreach(s;SplitString!("hello|world|this|is|a|test",'|'))
>	{
>		//use s as const
>	}
>}

I've never done this myself, but there is an example of a metaprogramming regex parser at the bottom of this page:

http://www.digitalmars.com/d/templates-revisited.html

Kevin

Kevin Bealer wrote:
> I've never done this myself, but there is an example of a metaprogramming regex
> parser at the bottom of this page:
> 
> http://www.digitalmars.com/d/templates-revisited.html
> 
> Kevin

If actually splitting the string doesn't work then maybe you can manage to have it generate a tuple of ints that represent the split points.


--bb

Bill Baxter wrote:
> Kevin Bealer wrote:
> 
>> I've never done this myself, but there is an example of a metaprogramming regex
>> parser at the bottom of this page:
>>
>> http://www.digitalmars.com/d/templates-revisited.html
>>
>> Kevin
> 
> 
> If actually splitting the string doesn't work then maybe you can manage to have it generate a tuple of ints that represent the split points.
> 
> 
> --bb

This is what I ended up using (and it actually does a better job for what I was trying to do) it returns a tuple.

/************
	Return a slice up-to but not including the first instance of t.
*/
template UseTill(char[] string, char t)
{
	static if(string == "" || string[0] == t)
		const char[] UseTill = "";
	else
		const char[] UseTill = string[0..1] ~ UseTill!(string[1..$],t);
}

/***********
	Return a slice starting after the first instance of t and containing the rest of the string.
*/
template DiscardTill(char[] string, char t)
{
	static if(string == "")
		const char[] DiscardTill = "";
	else static if(string[0] == t)
		const char[] DiscardTill = string[1..$];
	else
		const char[] DiscardTill = DiscardTill!(string[1..$],t);
}

/***********
	mixin temp with {V + 'string' broken up by 'c'}
*/
template BreakBy(char[] string, char d, V...)
{
	static if(string == "")
		alias V BreakBy;
	else static
		alias BreakBy!(DiscardTill!(string,d), d, V, UseTill!(string,d)) BreakBy;
}