lumiera_/src/lib/query.hpp

116 lines
3.2 KiB
C++

/*
QUERY.hpp - interface for capability queries
Copyright (C) Lumiera.org
2008, Hermann Vosseler <Ichthyostega@web.de>
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., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#ifndef LUMIERA_QUERY_H
#define LUMIERA_QUERY_H
#include <string>
#include <typeinfo>
#include "lib/symbol.hpp"
namespace lumiera {
using lib::Symbol;
using lib::Literal;
using std::string;
using boost::format;
/* ==== common definitions for rule based queries ==== */
/**
* Generic query interface for retrieving objects
* matching the given capability query
* @note until really integrating a rules based system
* this is a dummy placeholder implementation
* based on a dressed-up std::string
* @warning in this preliminary implementation, the
* given query-string is used as-is, without any
* normalisation. Moreover, as espeically the
* fake-configrules match by string comparision,
* this may led to unexpected mis-matches.
* @todo the »real thing« should be based on a
* normalised syntax tree representation
* of the atoms in the query.
*/
template<class OBJ>
class Query
{
std::string predicateForm_;
public:
explicit Query (string const& predicate="")
: predicateForm_(predicate)
{ }
void
clear()
{
predicateForm_.clear();
}
operator string() const { return predicateForm_; }
// operator string& () { return predicateForm_; } //TICKET #710 : needed temporarily by fake-configrules
}; // for calling removeTerm on the string-ref....
namespace query {
/** ensure standard format for a given id string.
* Trim, sanitise and ensure the first letter is lower case.
* @note modifies the given string ref in place
*/
void normaliseID (string& id);
/** count the top-level predicates in the query string.
* usable for ordering queries, as more predicates usually
* mean more conditions, i.e. more constriction
*/
uint countPred (const string&);
const string extractID (Symbol, const string& termString);
const string removeTerm (Symbol, string& termString);
template<typename TY>
const string
buildTypeID()
{
string typeID (typeid(TY).name());
normaliseID (typeID);
return typeID;
}
}} // namespace lumiera::query
#endif