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/**
 * Authors: k.inaba
 * License: NYSL 0.9982 http://www.kmonos.net/nysl/
 *
 * Common tricks and utilities for programming in D.
 */
module tricks.tricks;
import tricks.test;
import std.array      : appender;
import std.format     : formattedWrite;
import core.exception : AssertError;

/// Simple Wrapper for std.format.doFormat

string sprintf(string fmt, T...)(T params)
{
	auto writer = appender!string();
	formattedWrite(writer, fmt, params);
	return writer.data;
}

unittest
{
	assert( sprintf!"%s == %d"("1+2", 3)   == "1+2 == 3" );
	assert( sprintf!"%s == %04d"("1+2", 3) == "1+2 == 0003" );
}

/// Create an exception with automatically completed filename and lineno information

auto genex(ExceptionType, string fn=__FILE__, int ln=__LINE__, T...)(T params)
{
	static if( T.length > 0 && is(T[$-1] : Throwable) )
		return new ExceptionType(params[0..$-1], fn, ln, params[$-1]);
	else
		return new ExceptionType(params, fn, ln);
}

unittest
{
	assert_ne( genex!Exception("msg").file, "" );
	assert_ne( genex!Exception("msg").line, 0 );
	assert_ne( genex!Exception("msg",new Exception("bar")).next, Exception.init );
}

/// Mixing-in the bean constructor for a class

/*mixin*/
template SimpleConstructor()
{
	static if( is(typeof(super) == Object) || super.tupleof.length==0 )
		this( typeof(this.tupleof) params )
		{
			static if(this.tupleof.length>0)
				this.tupleof = params;
		}
	else
		this( typeof(super.tupleof) ps, typeof(this.tupleof) params )
		{
			// including (only) the direct super class members
			// may not always be a desirable choice, but should work for many cases
			super(ps);
			static if(this.tupleof.length>0)
				this.tupleof = params;
		}
}

unittest
{
	class Temp
	{
		int x;
		string y;
		mixin SimpleConstructor;
	}
	assert_eq( (new Temp(1,"foo")).x, 1 );
	assert_eq( (new Temp(1,"foo")).y, "foo" );
	assert( !__traits(compiles, new Temp) );
	assert( !__traits(compiles, new Temp(1)) );
	assert( !__traits(compiles, new Temp("foo",1)) );

	class Tomp : Temp
	{
		real z;
		mixin SimpleConstructor;
	}
	assert_eq( (new Tomp(1,"foo",2.5)).x, 1 );
	assert_eq( (new Tomp(1,"foo",2.5)).y, "foo" );
	assert_eq( (new Tomp(1,"foo",2.5)).z, 2.5 );
	assert( !__traits(compiles, new Tomp(3.14)) );

	// shiyo- desu. Don't use in this way.
	//   Tamp tries to call new Tomp(real) (because it only sees Tomp's members),
	//   but it fails because Tomp takes (int,string,real).
	assert( !__traits(compiles, {
		class Tamp : Tomp
		{
			mixin SimpleConstructor;
		}
	}) );
}

/// Mixing-in the MOST-DERIVED-member-wise comparator for a class

/*mixin*/
template SimpleCompare()
{
	override bool opEquals(Object rhs_) const
	{
		if( auto rhs = cast(typeof(this))rhs_ )
		{
			foreach(i,_; this.tupleof)
				if( this.tupleof[i] != rhs.tupleof[i] )
					return false;
			return true;
		}
		assert(false, sprintf!"Cannot compare %s with %s"(typeid(this), typeid(rhs_)));
	}

	override hash_t toHash() const
	{
		hash_t h = 0;
		foreach(mem; this.tupleof)
			h += typeid(mem).getHash(&mem);
		return h;
	}

	override int opCmp(Object rhs_) const
	{
		if( auto rhs = cast(typeof(this))rhs_ )
		{
			foreach(i,_; this.tupleof)
				if(auto c = typeid(_).compare(&this.tupleof[i],&rhs.tupleof[i]))
					return c;
			return 0;
		}
		assert(false, sprintf!"Cannot compare %s with %s"(typeid(this), typeid(rhs_)));
	}
}

unittest
{
	class Temp
	{
		int x;
		string y;
		mixin SimpleConstructor;
		mixin SimpleCompare;
	}
	assert_eq( new Temp(1,"foo"), new Temp(1,"foo") );
	assert_eq( (new Temp(1,"foo")).toHash, (new Temp(1,"foo")).toHash );
	assert_ne( new Temp(1,"foo"), new Temp(2,"foo") );
	assert_ne( new Temp(1,"foo"), new Temp(1,"bar") );
	assert_gt( new Temp(1,"foo"), new Temp(1,"bar") );
	assert_lt( new Temp(1,"foo"), new Temp(2,"bar") );
	assert_ge( new Temp(1,"foo"), new Temp(1,"foo") );

	class TempDummy
	{
		int x;
		string y;
		mixin SimpleConstructor;
		mixin SimpleCompare;
	}
	assert_throw!AssertError( new Temp(1,"foo") == new TempDummy(1,"foo") );
	assert_throw!AssertError( new Temp(1,"foo") <= new TempDummy(1,"foo") );
}

/// Mixing-in a simple toString method

/*mixin*/
template SimpleToString()
{
	override string toString()
	{
		string str = sprintf!"%s("(typeof(this).stringof);
		foreach(i,mem; this.tupleof)
		{
			if(i) str ~= ",";
			static if( is(typeof(mem) == std.bigint.BigInt) )
				str ~= std.bigint.toDecimalString(mem);
			else
				str ~= sprintf!"%s"(mem);
		}
		return str ~ ")";
	}
}

version(unittest) import std.bigint;
unittest
{
	class Temp
	{
		int x;
		string y;
		BigInt z;
		mixin SimpleConstructor;
		mixin SimpleToString;
	}
	assert_eq( (new Temp(1,"foo",BigInt(42))).toString(), "Temp(1,foo,42)" );
}

/// Everything is in

/*mixin*/
template SimpleClass()
{
	mixin SimpleConstructor;
	mixin SimpleCompare;
	mixin SimpleToString;
}