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/** \file aptitude_resolver_cost_syntax.cc */
// Copyright (C) 2010 Daniel Burrows
// 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; see the file COPYING. If not, write to
// the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
// Boston, MA 02111-1307, USA.
#include "aptitude_resolver_cost_syntax.h"
#include <ostream>
#include <generic/util/parsers.h>
namespace
{
// Parser for individual cost entries.
//
// Cost entries consist of either a name or a scaling factor. Names
// have the form [a-zA-Z][a-zA-Z0-9-_]*; i.e, they must lead with a
// letter, but later letters can include other alphanumerics and
// hyphens. (quoted strings might come into play eventually, to
// support GUI users who don't want to know weird syntactic
// restrictions)
//
// Note that this is a lexeme parser and doesn't need to be wrapped.
class cost_entry_parser : public parsers::parser_base<cost_entry_parser, cost_component_structure::entry>
{
struct make_entry
{
typedef cost_component_structure::entry result_type;
result_type operator()(int scaling_factor, const boost::shared_ptr<std::string> &name) const
{
return result_type(*name, scaling_factor);
}
};
public:
template<typename ParseInput>
cost_component_structure::entry do_parse(ParseInput &input) const
{
using namespace parsers;
// TODO: a convenience routine to parse character sets would be
// nice.
// Note that "max" is not an allowed cost name, to make room for
// using it as an operator in future expansions.
return apply(make_entry(),
( ( (lexeme(integer()) << lexeme(ch('*'))) | val(1) ) << notFollowedBy(str("max")),
container(std::string(), lexeme(alpha() + many(alnum() | ch('-') | ch('_')))) )).parse(input);
}
void get_expected(std::ostream &out) const
{
out << "cost value";
}
};
class cost_component_structure_parser : public parsers::parser_base<cost_component_structure_parser, cost_component_structure>
{
struct make_cost_component_structure
{
typedef cost_component_structure result_type;
result_type operator()(cost_component_structure::op combining_op,
const boost::shared_ptr<std::vector<cost_component_structure::entry> > &entries) const
{
return cost_component_structure(combining_op, *entries);
}
};
// Probably the easiest way to decide whether to combine with
// "add" or "none". I could do this with just parsers below, but
// it would get ugly.
struct make_add_or_none_cost_component_structure
{
typedef cost_component_structure result_type;
result_type operator()(const boost::shared_ptr<std::vector<cost_component_structure::entry> > &entries) const
{
return cost_component_structure(entries->size() == 1
? cost_component_structure::combine_none
: cost_component_structure::combine_add,
*entries);
}
};
public:
template<typename ParseInput>
cost_component_structure do_parse(ParseInput &input) const
{
using namespace parsers;
// Parse plan: check for "max" up front first (and check that it
// can't be a cost component name). If we see it, parse an
// argument list to max(). Otherwise, parse one or more cost
// entries separated by '+'. If there's only one, we return a
// structure with the operator set to "none"; otherwise we set
// it to "add".
return ( (maybe(lexeme(str("max"))) >>
notFollowedBy(alnum() | ch('-') | ch('_')) >>
apply(make_cost_component_structure(),
( val(cost_component_structure::combine_max)
, lexeme(ch('('))
>> sepByPlus(lexeme(ch(',')),
cost_entry_parser())
<< lexeme(ch(')')) )))
| apply(make_add_or_none_cost_component_structure(),
sepByPlus(lexeme(ch('+')),
cost_entry_parser())) ).parse(input);
}
void get_expected(std::ostream &out) const
{
out << "a combination of cost components";
}
};
}
class unpack_parse_result_visitor : public boost::static_visitor<boost::shared_ptr<std::vector<cost_component_structure> > >
{
public:
boost::shared_ptr<std::vector<cost_component_structure> > operator()(const parsers::ParseException &ex) const
{
throw ResolverCostParseException(ex.what(),
ex.get_raw_msg(),
ex.get_line_number(),
ex.get_column_number());
}
boost::shared_ptr<std::vector<cost_component_structure> > operator()(const boost::shared_ptr<std::vector<cost_component_structure> > &rval) const
{
return rval;
}
};
boost::shared_ptr<std::vector<cost_component_structure> >
parse_cost_settings(const std::string &settings)
{
using namespace parsers;
boost::variant<boost::shared_ptr<std::vector<cost_component_structure> >, ParseException>
result = parsers::parse(settings, sepByPlus(lexeme(ch(',')), cost_component_structure_parser()) << eof());
return boost::apply_visitor(unpack_parse_result_visitor(),
result);
}
void dump_settings(std::ostream &out, const boost::shared_ptr<std::vector<cost_component_structure> > &settings)
{
out << *settings;
}
std::ostream &operator<<(std::ostream &out, const std::vector<cost_component_structure> &settings)
{
bool first_component = true;
for(std::vector<cost_component_structure>::const_iterator
settings_it = settings.begin(); settings_it != settings.end(); ++settings_it)
{
const std::vector<cost_component_structure::entry> &entries =
*settings_it->get_entries();
if(entries.empty())
continue;
if(first_component)
first_component = false;
else
out << ", ";
out << *settings_it;
}
return out;
}
std::ostream &operator<<(std::ostream &out, const boost::shared_ptr<std::vector<cost_component_structure> > &settings)
{
dump_settings(out, settings);
return out;
}
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