Write GUI applications in a compile-time abstract language

appserver.cxx

//      Write GUI applications in an compile-time abstract language
//      
//      Copyright 2011 Michał Papierski <michal@papierski.net>
//      
//      This program is free software; you can redistribute it and/or modify
//      it under the terms of the GNU General Public License as published by
//      the Free Software Foundation; either version 2 of the License, or
//      (at your option) any later version.
//      
//      This program is distributed in the hope that it will be useful,
//      but WITHOUT ANY WARRANTY; without even the implied warranty of
//      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//      GNU General Public License for more details.
//      
//      You should have received a copy of the GNU General Public License
//      along with this program; if not, write to the Free Software
//      Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
//      MA 02110-1301, USA.
#include <iostream>
#include <string>
#include <list>
#include <map>
#include <boost/lexical_cast.hpp>

using namespace std;

struct object
{
	virtual string description() const = 0;
	operator string() const { return description(); }
};

struct abstract_expr: object
{
};

template <typename T>
string toString(T t) { return (string)t; }

template <>
string toString(int t) { return boost::lexical_cast<string>(t); }

template <>
string toString(const char* t) { return string("\"") + t + '"'; }


template <typename T1, typename T2>
struct chain_op: abstract_expr
{
	T1 t1_;
	T2 t2_;
	
	chain_op(T1 t1, T2 t2): t1_(t1), t2_(t2) {}
	virtual string description() const
	{
		return t1_.description() + "\n" + t2_.description();
	}
	
	template <typename F1>
	chain_op<chain_op<T1, T2>, F1> operator,(F1 f1)
	{
		return chain_op<chain_op<T1, T2>, F1>(*this, f1);
	}
};




namespace expr
{
	template <typename T1, typename T2>
	struct add_impl: abstract_expr
	{
		T1 t1_;
		T2 t2_;
		add_impl(T1 t1, T2 t2): t1_(t1), t2_(t2) {}
		virtual string description() const
		{
			return t1_.description() + " + " + t2_.description();
		}
	};
	
	template <typename T1, typename T2>
	struct setvar_impl: abstract_expr
	{
		T1 t1_;
		T2 t2_;
		setvar_impl(T1 t1, T2 t2): t1_(t1), t2_(t2) {}
		
		virtual string description() const
		{
			return "var " + t1_.description() + " = " + t2_.description() + ';'; 
		}
		
		template <typename F1>
		chain_op<setvar_impl<T1, T2>, F1> operator,(F1 f1)
		{
			return chain_op<setvar_impl<T1, T2>, F1>(*this, f1);
		}
	};


	template <typename T>
	struct val_impl: abstract_expr
	{
		T val_;
		val_impl(T t): val_(t) {}
		
		virtual string description() const
		{
			return toString(val_);
		}
		
		template <typename F1>
		add_impl<val_impl<T>, F1> operator+(F1 f1)
		{
			return add_impl<val_impl<T>, F1>(*this, f1);
		}
	};

	template <typename T>
	val_impl<T>* val(T t) { return new val_impl<T>(t); }
	
	struct var_impl: abstract_expr
	{
		string varname_;
		var_impl(const string& varname): varname_(varname) {}
		
		template <typename T1>
		setvar_impl<var_impl, val_impl<T1> > operator=(T1 t1)
		{
			return setvar_impl<var_impl, val_impl<T1> >(*this, val_impl<T1>(t1));
		}
		
		virtual string description() const  { return varname_; }
	};
	
	var_impl var(const string& name) { return var_impl(name); }	
}

template <typename T1>
expr::add_impl<expr::val_impl<T1>, expr::var_impl> operator+(T1 t1, expr::var_impl t2)
{
	return expr::add_impl<expr::val_impl<T1>, expr::var_impl>(t1, t2);
}








template <typename T>
struct alert_impl: abstract_expr
{
	T message_;
	alert_impl(const T& message): message_(message) {}
	
	virtual string description() const
	{
		return "alert(" + message_.description() + ");";
	}
	
	template <typename F1>
	chain_op<alert_impl<T>, F1> operator,(F1 f1)
	{
		return chain_op<alert_impl<T>, F1>(*this, f1);
	}
};

template <typename T>
alert_impl<expr::val_impl<T> > alert(T t)
{
	return alert_impl<expr::val_impl<T> >(t);
}

struct debug: abstract_expr
{
	string message_;
	debug(const string& message): message_(message) {}
	
	virtual string description() const
	{
		return "debug(\"" + message_ + "\");";
	}
	
	template <typename F1>
	chain_op<debug, F1> operator,(F1 f1)
	{
		return chain_op<debug, F1>(*this, f1);
	}
};

struct function: object
{
	string name_;
	string code_;
	function() {}
	function(const string& name): name_(name) {}
	
	template <typename T>
	function& operator[](const T& t)
	{
		cout << __PRETTY_FUNCTION__ << endl;
		code_ = "var _" + name_ + " = function " + name_ + "()\n" +
			"{\n" + t.description() + "\n}";
		return *this;
	}
	
	virtual string description() const
	{
		return code_;
	}
};

struct widgethide_impl: abstract_expr
{
	string name_;
	widgethide_impl(const string& name): name_(name) {}
	virtual string description() const
	{
		return "document.getElementByName(\"" + name_ + "\").visible = false;";
	}	
};

struct widget: object
{
	string widgetName_;
	widget(const string& widgetName): widgetName_(widgetName) {}
	
	map<string /* event */, function /* code */> events_;
	
	virtual string description() const
	{
		string out = '<' + widgetName_ + ' ';
		for (map<string, function>::const_iterator it(events_.begin()),
			end(events_.end()); it != end; ++it)
		{
			out += it->first + "=\"javascript:_" + it->second.name_ + "()\" ";
		}
		return out + '>';
	}
	
	widgethide_impl hide()
	{
		return widgethide_impl(widgetName_);
	}
};

struct button: widget
{
	button(): widget("button") {}
};

struct application: object
{
	application() {}
	list<widget*> dom_;
	
	virtual string description() const
	{
		string script, temp;
		for (list<widget*>::const_iterator it(dom_.begin()),
			end(dom_.end()); it != end; ++it)
		{
			for (map<string, function>::const_iterator it2((*it)->events_.begin()),
				end2((*it)->events_.end()); it2 != end2; ++it2)
			{
				script += it2->second.description() + '\n';
			}
			temp += (*it)->description();
		}
		return script + '\n' + temp;
	}
};

template <typename T>
struct if_impl: abstract_expr
{
	T cond_;
	string truestmt_;
	string falsestmt_;
	
	if_impl(T cond): cond_(cond) {}
	
	template <typename F1>
	if_impl& operator[](F1 f1)
	{
		truestmt_ = f1.description();
		return *this;
	}
	
	virtual string description() const
	{
		return "if (" + cond_.description() + ")\n" +
			"{\n" +
			truestmt_ + '\n' +
			"}";
	}
};

template <typename T>
if_impl<T> if_(T t)
{
	return if_impl<T>(t);
}

/*
 * 
 * "asdf" + var("var1")
 * expression_impl<const char*, var_impl>
 * "\"asdf\" + var("var1") + "\""
 * 
 */
int main(int argc, char **argv)
{
	using namespace expr;
	application app;
	
	button* btn1 = new button;
	btn1->events_["onclick"] = function("jp2gmd")[
		var("asdf1") = 5,
		var("asdf2") = "hello world",
		alert("asdf1 = " + var("asdf1")),
		alert("asdf2 = " + var("asdf2"))
	];
	
	button* btn2 = new button;
	btn2->events_["onclick"] = function("dupa")[
		alert("Test"),
		widget("btn1").hide(),
		widget("btn2").hide()
	];
	
	app.dom_.push_back(btn1);
	app.dom_.push_back(btn2);
	
	cout << app.description() << endl;
	
	return 0;
}