Anyone interested in a Spirit for D?

[BCS]

Walter Bright wrote:
> Bill Baxter wrote:
> 
>> But given Don's experiments with compile-time text parsing in D, it's 
>> conceivable that in D the above parser could just be created with:
>>
>>    r = make_parser("real_number (',' real_number)*");
>>
>> I.e. use the EBNF version directly in a string literal that gets 
>> parsed at compile time.
>> That would be pretty cool.
> 
> 
> Yes, it would be. But there's a catastrophic problem with it. Spirit 
> enables code snippets to be attached to terminals by overloading the [] 
> operator. If the EBNF was all in a string literal, this would be 
> impossible.


How about delegate literals for code snipits??


template parse(char[] rulename, char[] rule, T, T delegate(T[]) act)
{
	// mixin allows this to be used in the scope
	// parse!(rulename)(out T);

	// for rule ==
	// "AssignExpression | AssignExpression ',' Expression",
	// parse!(rulename) expand to something like this

		// mixin a specialization
	bool parse!(rulename)(out T ret)
	{
		T[2] set
		if(T* ret = rule!("AssignExpression")(set[0]))
		{
			ret = act[0](set);
			return true;
		}
		if(rule!("AssignExpression")(set[0]) &&
			rule!("Expression")(set[1]))
		{
			ret = act[1](set);
			return true;
		}
		false;
	}
	
}

///used something like this

class Parser : RootParser
{
	mixin parse("Expression",
			"
			AssignExpression |
			AssignExpression ',' Expression
			",
		Expr,
		[
		(Expr[] e){return e[0];},
		(Expr[] e){return new Expr(e[0], e[1]);}
		]
		);

	mixin parse("AssignExpression",
			"
			ConditionalExpression |
			ConditionalExpression '=' AssignExpression |
			ConditionalExpression '+=' AssignExpression
			"
		Expr,
		[
		(Expr[] e){return e[0];},
		(Expr[] e){return new AssignExper(e[0], e[1]);},
		(Expr[] e){return new AssignExper(e[0], e[1]);}
		]
		);

}

//// I've never used mixins so I most likely have something wrong in there