/// @file parser_compat.cpp Parser interface compatible with the old
///       (bison/flex based) parser.
#include "ex.h"
#include "idx.h"
#include "lst.h"
#include "parser.hpp"
#include <string>
#include <iostream>

namespace GiNaC
{
static symtab make_symtab(const ex& l);

ptr<basic> ex::construct_from_string_and_lst(const std::string &s, const ex &l)
{
	static const bool strict = true;
	symtab syms = make_symtab(l);
	parser reader(syms, strict); 
	ex parsed_ex = reader(s);
	return parsed_ex.bp;
}

static std::string get_symbol_name(const ex & s);

static symtab make_symtab(const ex& l)
{
	symtab syms;
	if (is_exactly_a<lst>(l)) {
		for (std::size_t i = 0; i < l.nops(); i++) {
			const ex &o = l.op(i);
			if (is_a<symbol>(o) || (is_a<idx>(o) && is_a<symbol>(o.op(0))))
				syms[get_symbol_name(o)] = o;
		}
	}
	return syms;
}

static std::string get_symbol_name(const ex & s)
{
	if (is_a<symbol>(s))
		return ex_to<symbol>(s).get_name();
	else if (is_a<idx>(s) && is_a<symbol>(s.op(0)))
		return ex_to<symbol>(s.op(0)).get_name();
	else
		throw (std::invalid_argument("get_symbol_name(): unexpected expression type"));
}

}