/*==========================================================================
 * newforeach.d
 *    Written in the D Programming Language (http://www.digitalmars.com/d)
 */
/***************************************************************************
 * <TODO: Module Summary>
 *
 * <TODO: Description>
 *
 * Authors:  William V. Baxter III
 * Date: 05 Jan 2008
 * Copyright: (C) 2007  William Baxter
 */
//===========================================================================

module newforeach;
import std.stdio;

enum {BREAK=1,RETURN}

alias string T;

void do_something() {
    writefln("  Doing something");
}

struct Apply(Args...) 
{
    alias void delegate(Args) LoopBody;
    LoopBody _loop_body;
    int* _ret = null;

    void _call(Args a) { 
        if (_ret) *_ret = 0;
        _loop_body(a); // may set *_ret!
    }
}

class Class {
    T[] values;

    void opApply( Apply!(T) dg) {
        foreach(x; values) {
            //yield(dg, x);
            dg._call(x);
            if (dg._ret && *dg._ret) return;
        }
    }
}


void test(T[] obj_values)
{
    auto obj = new Class;
    obj.values = obj_values;

    writefln("before foreach over %s", obj.values);

    //The user's foreach:
    //foreach(x; obj) {
    //    writefln("x is ", x);
    //    if (x=="two") break;
    //    if (x=="three") return;
    //    do_something;
    //}
    // Hypothetically generated foreach code:
    int _ret = 0;
    void _loop_body(/*ref*/ T x)
    {
        writefln("x is ", x);
        if (x=="two") { _ret = BREAK; return; }
        if (x=="three") { _ret = RETURN; return; }
        do_something;
    }
    obj.opApply( Apply!(T)(&_loop_body, &_ret) );
    writefln("(_ret code: %s)", _ret);
    if (_ret==RETURN) return;

    writefln("after foreach");

}


void main()
{
    test(["one"[],"two", "three", "four"]);
    writefln;
    test(["four"[],"one", "three", "two"]);

}
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