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/*
Copyright (C) 2008-2015, 2018-2019 Free Software Foundation, Inc.
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 3 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, see <http://www.gnu.org/licenses/>.
*/
%require "3.2"
%debug
%language "c++"
%define api.token.constructor
%define api.value.type variant
%define api.value.automove
%define api.location.file none
%define parse.assert
%locations
%code requires // *.hh
{
#include <memory> // std::unique_ptr
#include <string>
#include <vector>
using string_uptr = std::unique_ptr<std::string>;
using string_uptrs = std::vector<string_uptr>;
}
%code // *.cc
{
#include <climits> // INT_MIN, INT_MAX
#include <iostream>
#include <sstream>
namespace yy
{
// Prototype of the yylex function providing subsequent tokens.
static parser::symbol_type yylex ();
// Print a vector of strings.
std::ostream&
operator<< (std::ostream& o, const string_uptrs& ss)
{
o << '{';
const char *sep = "";
for (const auto& s: ss)
{
o << sep << *s;
sep = ", ";
}
return o << '}';
}
}
template <typename... Args>
string_uptr
make_string_uptr (Args&&... args)
{
// std::make_unique is C++14.
return string_uptr (new std::string{std::forward<Args> (args)...});
}
}
%token <string_uptr> TEXT;
%token <int> NUMBER;
%printer { yyo << '(' << &$$ << ") " << $$; } <*>;
%printer { yyo << *$$; } <string_uptr>;
%token END_OF_FILE 0;
%type <string_uptr> item;
%type <string_uptrs> list;
%%
result:
list { std::cout << $1 << '\n'; }
;
list:
%empty { /* Generates an empty string list */ }
| list item { $$ = $1; $$.emplace_back ($2); }
;
item:
TEXT
| NUMBER { $$ = make_string_uptr (std::to_string ($1)); }
;
%%
// The last number return by the scanner is max - 1.
int max = 4;
namespace yy
{
// The yylex function providing subsequent tokens:
// TEXT "I have three numbers for you."
// NUMBER 1
// NUMBER 2
// NUMBER ...
// NUMBER max - 1
// TEXT "And that's all!"
// END_OF_FILE
static
parser::symbol_type
yylex ()
{
static int count = 0;
const int stage = count;
++count;
auto loc = parser::location_type{nullptr, unsigned (stage + 1), unsigned (stage + 1)};
if (stage == 0)
return parser::make_TEXT (make_string_uptr ("I have numbers for you."), std::move (loc));
else if (stage < max)
return parser::make_NUMBER (stage, std::move (loc));
else if (stage == max)
return parser::make_TEXT (make_string_uptr ("And that's all!"), std::move (loc));
else
return parser::make_END_OF_FILE (std::move (loc));
}
// Mandatory error function
void
parser::error (const parser::location_type& loc, const std::string& msg)
{
std::cerr << loc << ": " << msg << '\n';
}
}
int
main (int argc, const char *argv[])
{
if (2 <= argc && isdigit (*argv[1]))
{
auto maxl = strtol (argv[1], nullptr, 10);
max = INT_MIN <= maxl && maxl <= INT_MAX ? int(maxl) : 4;
}
auto&& p = yy::parser{};
p.set_debug_level (!!getenv ("YYDEBUG"));
return p.parse ();
}
// Local Variables:
// mode: C++
// End:
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