150 lines
3.9 KiB
C++
150 lines
3.9 KiB
C++
/*
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Query - interface for capability queries
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Copyright (C) Lumiera.org
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2008, Hermann Vosseler <Ichthyostega@web.de>
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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* *****************************************************/
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#include "common/query.hpp"
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#include "common/util.hpp"
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#include "nobugcfg.h"
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#include <boost/algorithm/string.hpp>
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#include <boost/regex.hpp>
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#include <map>
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using std::map;
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using boost::regex;
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using boost::smatch;
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using boost::regex_search;
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using boost::sregex_iterator;
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using util::contains;
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using util::isnil;
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namespace lumiera
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{
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namespace query
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{
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namespace // local definitions
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{
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typedef boost::function<bool(string::value_type)> ChPredicate;
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ChPredicate is_alpha = boost::algorithm::is_alpha();
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ChPredicate is_upper = boost::algorithm::is_upper();
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} // local defs
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void
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normalizeID (string& id)
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{
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id = util::sanitize(id);
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if (isnil(id) || !is_alpha (id[0]))
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id.insert(0, "o");
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REQUIRE (!isnil(id));
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REQUIRE (is_alpha (id[0]));
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char first = id[0];
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if (is_upper (first))
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id[0] = std::tolower (first);
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}
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namespace // Implementation details
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{
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map<Symbol, regex> regexTable;
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Symbol matchArgument = "\\(\\s*([\\w_\\.\\-]+)\\s*\\),?\\s*";
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regex findPredicate (string("(\\w+)")+matchArgument);
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inline regex&
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getTermRegex (Symbol sym)
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{
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if (!contains (regexTable, sym))
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regexTable[sym] = regex (string(sym)+=matchArgument);
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return regexTable[sym];
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}
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}
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/** (preliminary) helper: instead of really parsing and evaluating the terms,
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* just do a regular expression match to extract the literal argument
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* behind the given predicate symbol. e.g calling
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* queryID ("stream", "id(abc), stream(mpeg)")
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* yields "mpeg"
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*/
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const string
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extractID (Symbol sym, const string& termString)
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{
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smatch match;
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if (regex_search (termString, match, getTermRegex (sym)))
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return (match[1]);
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else
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return "";
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}
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/** (preliminary) helper: cut a term with the given symbol.
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* The term is matched, removed from the original string and returned
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* @note parameter termString will be modified!
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*/
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const string
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removeTerm (Symbol sym, string& termString)
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{
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smatch match;
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if (regex_search (termString, match, getTermRegex (sym)))
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{
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string res (sym); res += "("+match[1]+")";
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termString.erase (match.position(), match[0].length());
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return res;
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}
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else
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return "";
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}
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/** @note this is a very hackish preliminary implementation.
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* The regex used will flounder when applied to nested terms.
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* We need a real parser for predicate logic terms (which we
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* probably get for free when we embed a prolog system)...
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*/
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uint
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countPraed (const string& q)
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{
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uint cnt (0);
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sregex_iterator end;
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for (sregex_iterator i (q.begin(),q.end(), findPredicate);
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i != end; ++i)
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++cnt;
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return cnt;
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}
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} // namespace query
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/** */
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} // namespace lumiera
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