Re: How to use retro over findSplitBefore result?

[Jesse Phillips]

On Wednesday, 4 December 2013 at 17:43:22 UTC, MrSmith wrote:
I am trying to compile following code
import std.algorithm : findSplitBefore;
import std.range : retro;
import std.array : array;

// returns file path where name has suffix and prefix
string withSuffixPrefix(string filePath, string prefix, string 
suffix)
{
    auto splitted = filePath.retro.findSplitBefore("/");

    return cast(string)splitted[1].retro.array
                ~ prefix
                ~ cast(string)splitted[0].retro.array //Fails!
                ~ suffix;
}

The casting you've placed in there scares me. The returned range 
is going to be of dchar, assuming you're interested in UTF 
support, you'll want a conversion not a cast, I recommend 
std.conv.to!string. But even this is too much so I've commented 
that out and replaced it with a somewhat lazy approach:

import std.algorithm : findSplitBefore;
import std.range : retro, chain;
import std.array : array;
import std.conv : to;

// returns file path where name has suffix and prefix
string withSuffixPrefix(string filePath, string prefix, string
suffix)
{
    auto splitted = filePath.retro.findSplitBefore("/");

    //return splitted[1].array.retro.to!string
        //      ~ prefix
        //      ~ splitted[0].array.retro.to!string
        //      ~ suffix;
    return chain(splitted[1].array.retro,
                prefix,
                splitted[0].array.retro,
                suffix).array;
}

void main() {
        assert(withSuffixPrefix("/some/random/path/to/file", "pref-",
                  ".fl") == "/some/random/path/to/pref-file.fl");
}