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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 polemy.tricks;
static import std.array;
static import std.format;
static import core.exception;

/// Simple Wrapper for std.format.doFormat

string sprintf(string fmt, T...)(T params)
{
	auto writer = std.array.appender!string();
	std.format.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" );
}

/// Unittest helpers asserting two values are in some relation ==, !=, <, <=, >, >=

template assertOp(string op)
{
	void assertOp(A, B, string fn=__FILE__, int ln=__LINE__)(A a, B b, string msg="")
	{
		try {
			if( mixin("a"~op~"b") ) return;
		} catch(Throwable e) {
			core.exception.onAssertErrorMsg(fn, ln, msg.length ? msg : sprintf!"exception [%s]"(e));
		}
		core.exception.onAssertErrorMsg(fn, ln, msg.length ? msg : sprintf!"%s !%s %s"(a,op,b));
	}
}

alias assertOp!(`==`) assert_eq;
alias assertOp!(`!=`) assert_ne;
alias assertOp!(`<`)  assert_lt;
alias assertOp!(`<=`) assert_le;
alias assertOp!(`>`)  assert_gt;
alias assertOp!(`>=`) assert_ge;

/// Unittest helper that asserts an expression must throw something

void assert_throw(ExceptionType, T, string fn=__FILE__, int ln=__LINE__)(lazy T t, string msg="")
{
	try {
		t();
	} catch(ExceptionType) {
		return;
	} catch(Throwable e) {
		core.exception.onAssertErrorMsg(fn, ln, msg.length ? msg : sprintf!"exception [%s]"(e));
	}
	core.exception.onAssertErrorMsg(fn, ln, msg.length ? msg : "no execption");
}

/// Unittest helper that asserts an expression must not throw anything

void assert_nothrow(ExceptionType, T, string fn=__FILE__, int ln=__LINE__)(lazy T t, string msg="")
{
	try {
		t();
	} catch(Throwable e) {
		core.exception.onAssertErrorMsg(fn, ln, msg.length ? msg : sprintf!"exception [%s]"(e));
	}
}

/* [Todo] is there any way to clearnly implement "assert_compiles" and "assert_not_compile"? */

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

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)) );
}

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

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") );
}