lower case only first letter of word

[Ali Çehreli]

On 12/05/2017 11:41 AM, kdevel wrote:
> On Tuesday, 5 December 2017 at 17:25:57 UTC, Steven Schveighoffer wrote:

> But one cannot use the return value of lowerCaseFirst as argument for 
> foo(string). Only the use as argument to writeln seems to work.

That's how ranges work. LowerCaseFirst produces dchar elements one at a 
time. An easy way of getting a string out of it is calling 
std.conv.text, which converts all those dchars to a series of UTF-8 chars.

Note, .text below is an expensive call because it allocates a new 
string. You may want to cache its result first if you need the result 
more than once:

     auto lowered = lowerCaseFirst("HELLO").text;
     foo(lowered);

This works:

import std.range;

struct LowerCaseFirst(R) // if(isSomeString!R)
{
    R src;
    bool notFirst; // terrible name, but I want default false
    dchar front() {
       import std.uni: toLower;
       return notFirst ? src.front : src.front.toLower;
    }
    void popFront() { notFirst = true; src.popFront; }
    bool empty() { return src.empty; }
}

auto lowerCaseFirst(R)(R r)
{
    return LowerCaseFirst!R(r);
}

void foo(string s) {
     import std.stdio;
     writefln("good old string: %s", s);
}

void main() {
     import std.conv;
     foo(lowerCaseFirst("HELLO").text);
}

Ali