kea/src/lib/eval/parser.yy

/* Copyright (C) 2015-2016 Internet Systems Consortium, Inc. ("ISC")

   This Source Code Form is subject to the terms of the Mozilla Public
   License, v. 2.0. If a copy of the MPL was not distributed with this
   file, You can obtain one at http://mozilla.org/MPL/2.0/. */

%skeleton "lalr1.cc" /* -*- C++ -*- */
%require "3.0.0"
%defines
%define parser_class_name {EvalParser}
%define api.token.constructor
%define api.value.type variant
%define api.namespace {isc::eval}
%define parse.assert
%code requires
{
#include <string>
#include <eval/token.h>
#include <eval/eval_context_decl.h>
#include <dhcp/option.h>
#include <boost/lexical_cast.hpp>

using namespace isc::dhcp;
using namespace isc::eval;
}
// The parsing context.
%param { EvalContext& ctx }
%locations
%define parse.trace
%define parse.error verbose
%code
{
# include "eval_context.h"
}

%define api.token.prefix {TOKEN_}
%token
  END  0  "end of file"
  EQUAL "=="
  OPTION "option"
  SUBSTRING "substring"
  CONCAT "concat"
  NOT "not"
  AND "and"
  OR "or"
  TEXT "text"
  RELAY4 "relay4"
  HEX "hex"
  EXISTS "exists"
  ALL "all"
  DOT "."
  COMA ","
  LPAREN  "("
  RPAREN  ")"
  LBRACKET "["
  RBRACKET "]"
;

%token <std::string> STRING "constant string"
%token <std::string> INTEGER "integer"
%token <std::string> HEXSTRING "constant hexstring"
%token <std::string> OPTION_NAME "option name"

%type <uint16_t> option_code
%type <TokenOption::RepresentationType> option_repr_type

%left OR
%left AND
%precedence NOT

%printer { yyoutput << $$; } <*>;

%%

// The whole grammar starts with an expression.
%start expression;

// Expression can either be a single token or a (something == something) expression

expression : bool_expr
           ;

bool_expr : "(" bool_expr ")"
          | NOT bool_expr
                {
                    TokenPtr neg(new TokenNot());
                    ctx.expression.push_back(neg);
                }
          | bool_expr AND bool_expr
                {
                    TokenPtr neg(new TokenAnd());
                    ctx.expression.push_back(neg);
                }
          | bool_expr OR bool_expr
                {
                    TokenPtr neg(new TokenOr());
                    ctx.expression.push_back(neg);
                }
          | string_expr EQUAL string_expr
                {
                    TokenPtr eq(new TokenEqual());
                    ctx.expression.push_back(eq);
                }
          | OPTION "[" option_code "]" "." EXISTS
                {
                    TokenPtr opt(new TokenOption($3, TokenOption::EXISTS));
                    ctx.expression.push_back(opt);
                }
          ;

string_expr : STRING
                  {
                      TokenPtr str(new TokenString($1));
                      ctx.expression.push_back(str);
                  }
            | HEXSTRING
                  {
                      TokenPtr hex(new TokenHexString($1));
                      ctx.expression.push_back(hex);
                  }
            | OPTION "[" option_code "]" "." option_repr_type
                  {
                      TokenPtr opt(new TokenOption($3, $6));
                      ctx.expression.push_back(opt);
                  }
            | RELAY4 "[" option_code "]" "." option_repr_type
                  {
                     switch (ctx.getUniverse()) {
                     case Option::V4:
                     {
                         TokenPtr opt(new TokenRelay4Option($3, $6));
                         ctx.expression.push_back(opt);
                         break;
                     }
                     case Option::V6:
                         // We will have relay6[123] for the DHCPv6.
                         // In a very distant future we'll possibly be able
                         // to mix both if we have DHCPv4-over-DHCPv6, so it
                         // has some sense to make it explicit whether we
                         // talk about DHCPv4 relay or DHCPv6 relay. However,
                         // for the time being relay4 can be used in DHCPv4
                         // only.
                         error(@1, "relay4 can only be used in DHCPv4.");
                     }
                  }
            | SUBSTRING "(" string_expr "," start_expr "," length_expr ")"
                  {
                      TokenPtr sub(new TokenSubstring());
                      ctx.expression.push_back(sub);
                  }
            | CONCAT "(" string_expr "," string_expr ")"
                  {
                      TokenPtr conc(new TokenConcat());
                      ctx.expression.push_back(conc);
                  }
            ;

option_code : INTEGER
                 {
                     $$ = ctx.convertOptionCode($1, @1);
                 }
            | OPTION_NAME
                 {
                     $$ = ctx.convertOptionName($1, @1);
                 }
            ;

option_repr_type : TEXT
                      {
                          $$ = TokenOption::TEXTUAL;
                      }
                 | HEX
                      {
                          $$ = TokenOption::HEXADECIMAL;
                      }
                 ;

start_expr : INTEGER
                 {
                     TokenPtr str(new TokenString($1));
                     ctx.expression.push_back(str);
                 }
           ;

length_expr : INTEGER
                  {
                      TokenPtr str(new TokenString($1));
                      ctx.expression.push_back(str);
                  }
            | ALL
                 {
                     TokenPtr str(new TokenString("all"));
                     ctx.expression.push_back(str);
                 }
            ;

%%
void
isc::eval::EvalParser::error(const location_type& loc,
                             const std::string& what)
{
    ctx.error(loc, what);
}