[binutils-gdb.git] / gdb / c-exp.y

/* YACC parser for C expressions, for GDB.
   Copyright (C) 1986, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997,
   1998, 1999, 2000, 2003, 2004, 2006, 2007, 2008, 2009
   Free Software Foundation, Inc.

   This file is part of GDB.

   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/>.  */

/* Parse a C expression from text in a string,
   and return the result as a  struct expression  pointer.
   That structure contains arithmetic operations in reverse polish,
   with constants represented by operations that are followed by special data.
   See expression.h for the details of the format.
   What is important here is that it can be built up sequentially
   during the process of parsing; the lower levels of the tree always
   come first in the result.

   Note that malloc's and realloc's in this file are transformed to
   xmalloc and xrealloc respectively by the same sed command in the
   makefile that remaps any other malloc/realloc inserted by the parser
   generator.  Doing this with #defines and trying to control the interaction
   with include files (<malloc.h> and <stdlib.h> for example) just became
   too messy, particularly when such includes can be inserted at random
   times by the parser generator.  */
   
%{

#include "defs.h"
#include "gdb_string.h"
#include <ctype.h>
#include "expression.h"
#include "value.h"
#include "parser-defs.h"
#include "language.h"
#include "c-lang.h"
#include "bfd.h" /* Required by objfiles.h.  */
#include "symfile.h" /* Required by objfiles.h.  */
#include "objfiles.h" /* For have_full_symbols and have_partial_symbols */
#include "charset.h"
#include "block.h"
#include "cp-support.h"
#include "dfp.h"
#include "gdb_assert.h"
#include "macroscope.h"

#define parse_type builtin_type (parse_gdbarch)

/* Remap normal yacc parser interface names (yyparse, yylex, yyerror, etc),
   as well as gratuitiously global symbol names, so we can have multiple
   yacc generated parsers in gdb.  Note that these are only the variables
   produced by yacc.  If other parser generators (bison, byacc, etc) produce
   additional global names that conflict at link time, then those parser
   generators need to be fixed instead of adding those names to this list. */

#define yymaxdepth c_maxdepth
#define yyparse c_parse_internal
#define yylex   c_lex
#define yyerror c_error
#define yylval  c_lval
#define yychar  c_char
#define yydebug c_debug
#define yypact  c_pact  
#define yyr1    c_r1                    
#define yyr2    c_r2                    
#define yydef   c_def           
#define yychk   c_chk           
#define yypgo   c_pgo           
#define yyact   c_act           
#define yyexca  c_exca
#define yyerrflag c_errflag
#define yynerrs c_nerrs
#define yyps    c_ps
#define yypv    c_pv
#define yys     c_s
#define yy_yys  c_yys
#define yystate c_state
#define yytmp   c_tmp
#define yyv     c_v
#define yy_yyv  c_yyv
#define yyval   c_val
#define yylloc  c_lloc
#define yyreds  c_reds          /* With YYDEBUG defined */
#define yytoks  c_toks          /* With YYDEBUG defined */
#define yyname  c_name          /* With YYDEBUG defined */
#define yyrule  c_rule          /* With YYDEBUG defined */
#define yylhs   c_yylhs
#define yylen   c_yylen
#define yydefred c_yydefred
#define yydgoto c_yydgoto
#define yysindex c_yysindex
#define yyrindex c_yyrindex
#define yygindex c_yygindex
#define yytable  c_yytable
#define yycheck  c_yycheck

#ifndef YYDEBUG
#define YYDEBUG 1               /* Default to yydebug support */
#endif

#define YYFPRINTF parser_fprintf

int yyparse (void);

static int yylex (void);

void yyerror (char *);

%}

/* Although the yacc "value" of an expression is not used,
   since the result is stored in the structure being created,
   other node types do have values.  */

%union
  {
    LONGEST lval;
    struct {
      LONGEST val;
      struct type *type;
    } typed_val_int;
    struct {
      DOUBLEST dval;
      struct type *type;
    } typed_val_float;
    struct {
      gdb_byte val[16];
      struct type *type;
    } typed_val_decfloat;
    struct symbol *sym;
    struct type *tval;
    struct stoken sval;
    struct typed_stoken tsval;
    struct ttype tsym;
    struct symtoken ssym;
    int voidval;
    struct block *bval;
    enum exp_opcode opcode;
    struct internalvar *ivar;

    struct stoken_vector svec;
    struct type **tvec;
    int *ivec;
  }

%{
/* YYSTYPE gets defined by %union */
static int parse_number (char *, int, int, YYSTYPE *);
%}

%type <voidval> exp exp1 type_exp start variable qualified_name lcurly
%type <lval> rcurly
%type <tval> type typebase qualified_type
%type <tvec> nonempty_typelist
/* %type <bval> block */

/* Fancy type parsing.  */
%type <voidval> func_mod direct_abs_decl abs_decl
%type <tval> ptype
%type <lval> array_mod

%token <typed_val_int> INT
%token <typed_val_float> FLOAT
%token <typed_val_decfloat> DECFLOAT

/* Both NAME and TYPENAME tokens represent symbols in the input,
   and both convey their data as strings.
   But a TYPENAME is a string that happens to be defined as a typedef
   or builtin type name (such as int or char)
   and a NAME is any other symbol.
   Contexts where this distinction is not important can use the
   nonterminal "name", which matches either NAME or TYPENAME.  */

%token <tsval> STRING
%token <tsval> CHAR
%token <ssym> NAME /* BLOCKNAME defined below to give it higher precedence. */
%token <voidval> COMPLETE
%token <tsym> TYPENAME
%type <sval> name
%type <svec> string_exp
%type <ssym> name_not_typename
%type <tsym> typename

/* A NAME_OR_INT is a symbol which is not known in the symbol table,
   but which would parse as a valid number in the current input radix.
   E.g. "c" when input_radix==16.  Depending on the parse, it will be
   turned into a name or into a number.  */

%token <ssym> NAME_OR_INT 

%token STRUCT CLASS UNION ENUM SIZEOF UNSIGNED COLONCOLON
%token TEMPLATE
%token ERROR

/* Special type cases, put in to allow the parser to distinguish different
   legal basetypes.  */
%token SIGNED_KEYWORD LONG SHORT INT_KEYWORD CONST_KEYWORD VOLATILE_KEYWORD DOUBLE_KEYWORD

%token <voidval> VARIABLE

%token <opcode> ASSIGN_MODIFY

/* C++ */
%token TRUEKEYWORD
%token FALSEKEYWORD


%left ','
%left ABOVE_COMMA
%right '=' ASSIGN_MODIFY
%right '?'
%left OROR
%left ANDAND
%left '|'
%left '^'
%left '&'
%left EQUAL NOTEQUAL
%left '<' '>' LEQ GEQ
%left LSH RSH
%left '@'
%left '+' '-'
%left '*' '/' '%'
%right UNARY INCREMENT DECREMENT
%right ARROW ARROW_STAR '.' DOT_STAR '[' '('
%token <ssym> BLOCKNAME 
%token <bval> FILENAME
%type <bval> block
%left COLONCOLON

\f
%%

start   :       exp1
        |       type_exp
        ;

type_exp:       type
                        { write_exp_elt_opcode(OP_TYPE);
                          write_exp_elt_type($1);
                          write_exp_elt_opcode(OP_TYPE);}
        ;

/* Expressions, including the comma operator.  */
exp1    :       exp
        |       exp1 ',' exp
                        { write_exp_elt_opcode (BINOP_COMMA); }
        ;

/* Expressions, not including the comma operator.  */
exp     :       '*' exp    %prec UNARY
                        { write_exp_elt_opcode (UNOP_IND); }
        ;

exp     :       '&' exp    %prec UNARY
                        { write_exp_elt_opcode (UNOP_ADDR); }
        ;

exp     :       '-' exp    %prec UNARY
                        { write_exp_elt_opcode (UNOP_NEG); }
        ;

exp     :       '+' exp    %prec UNARY
                        { write_exp_elt_opcode (UNOP_PLUS); }
        ;

exp     :       '!' exp    %prec UNARY
                        { write_exp_elt_opcode (UNOP_LOGICAL_NOT); }
        ;

exp     :       '~' exp    %prec UNARY
                        { write_exp_elt_opcode (UNOP_COMPLEMENT); }
        ;

exp     :       INCREMENT exp    %prec UNARY
                        { write_exp_elt_opcode (UNOP_PREINCREMENT); }
        ;

exp     :       DECREMENT exp    %prec UNARY
                        { write_exp_elt_opcode (UNOP_PREDECREMENT); }
        ;

exp     :       exp INCREMENT    %prec UNARY
                        { write_exp_elt_opcode (UNOP_POSTINCREMENT); }
        ;

exp     :       exp DECREMENT    %prec UNARY
                        { write_exp_elt_opcode (UNOP_POSTDECREMENT); }
        ;

exp     :       SIZEOF exp       %prec UNARY
                        { write_exp_elt_opcode (UNOP_SIZEOF); }
        ;

exp     :       exp ARROW name
                        { write_exp_elt_opcode (STRUCTOP_PTR);
                          write_exp_string ($3);
                          write_exp_elt_opcode (STRUCTOP_PTR); }
        ;

exp     :       exp ARROW name COMPLETE
                        { mark_struct_expression ();
                          write_exp_elt_opcode (STRUCTOP_PTR);
                          write_exp_string ($3);
                          write_exp_elt_opcode (STRUCTOP_PTR); }
        ;

exp     :       exp ARROW COMPLETE
                        { struct stoken s;
                          mark_struct_expression ();
                          write_exp_elt_opcode (STRUCTOP_PTR);
                          s.ptr = "";
                          s.length = 0;
                          write_exp_string (s);
                          write_exp_elt_opcode (STRUCTOP_PTR); }
        ;

exp     :       exp ARROW qualified_name
                        { /* exp->type::name becomes exp->*(&type::name) */
                          /* Note: this doesn't work if name is a
                             static member!  FIXME */
                          write_exp_elt_opcode (UNOP_ADDR);
                          write_exp_elt_opcode (STRUCTOP_MPTR); }
        ;

exp     :       exp ARROW_STAR exp
                        { write_exp_elt_opcode (STRUCTOP_MPTR); }
        ;

exp     :       exp '.' name
                        { write_exp_elt_opcode (STRUCTOP_STRUCT);
                          write_exp_string ($3);
                          write_exp_elt_opcode (STRUCTOP_STRUCT); }
        ;

exp     :       exp '.' name COMPLETE
                        { mark_struct_expression ();
                          write_exp_elt_opcode (STRUCTOP_STRUCT);
                          write_exp_string ($3);
                          write_exp_elt_opcode (STRUCTOP_STRUCT); }
        ;

exp     :       exp '.' COMPLETE
                        { struct stoken s;
                          mark_struct_expression ();
                          write_exp_elt_opcode (STRUCTOP_STRUCT);
                          s.ptr = "";
                          s.length = 0;
                          write_exp_string (s);
                          write_exp_elt_opcode (STRUCTOP_STRUCT); }
        ;

exp     :       exp '.' qualified_name
                        { /* exp.type::name becomes exp.*(&type::name) */
                          /* Note: this doesn't work if name is a
                             static member!  FIXME */
                          write_exp_elt_opcode (UNOP_ADDR);
                          write_exp_elt_opcode (STRUCTOP_MEMBER); }
        ;

exp     :       exp DOT_STAR exp
                        { write_exp_elt_opcode (STRUCTOP_MEMBER); }
        ;

exp     :       exp '[' exp1 ']'
                        { write_exp_elt_opcode (BINOP_SUBSCRIPT); }
        ;

exp     :       exp '(' 
                        /* This is to save the value of arglist_len
                           being accumulated by an outer function call.  */
                        { start_arglist (); }
                arglist ')'     %prec ARROW
                        { write_exp_elt_opcode (OP_FUNCALL);
                          write_exp_elt_longcst ((LONGEST) end_arglist ());
                          write_exp_elt_opcode (OP_FUNCALL); }
        ;

lcurly  :       '{'
                        { start_arglist (); }
        ;

arglist :
        ;

arglist :       exp
                        { arglist_len = 1; }
        ;

arglist :       arglist ',' exp   %prec ABOVE_COMMA
                        { arglist_len++; }
        ;

exp     :       exp '(' nonempty_typelist ')' const_or_volatile
                        { int i;
                          write_exp_elt_opcode (TYPE_INSTANCE);
                          write_exp_elt_longcst ((LONGEST) $<ivec>3[0]);
                          for (i = 0; i < $<ivec>3[0]; ++i)
                            write_exp_elt_type ($<tvec>3[i + 1]);
                          write_exp_elt_longcst((LONGEST) $<ivec>3[0]);
                          write_exp_elt_opcode (TYPE_INSTANCE);
                          free ($3);
                        }
        ;

rcurly  :       '}'
                        { $$ = end_arglist () - 1; }
        ;
exp     :       lcurly arglist rcurly   %prec ARROW
                        { write_exp_elt_opcode (OP_ARRAY);
                          write_exp_elt_longcst ((LONGEST) 0);
                          write_exp_elt_longcst ((LONGEST) $3);
                          write_exp_elt_opcode (OP_ARRAY); }
        ;

exp     :       lcurly type rcurly exp  %prec UNARY
                        { write_exp_elt_opcode (UNOP_MEMVAL);
                          write_exp_elt_type ($2);
                          write_exp_elt_opcode (UNOP_MEMVAL); }
        ;

exp     :       '(' type ')' exp  %prec UNARY
                        { write_exp_elt_opcode (UNOP_CAST);
                          write_exp_elt_type ($2);
                          write_exp_elt_opcode (UNOP_CAST); }
        ;

exp     :       '(' exp1 ')'
                        { }
        ;

/* Binary operators in order of decreasing precedence.  */

exp     :       exp '@' exp
                        { write_exp_elt_opcode (BINOP_REPEAT); }
        ;

exp     :       exp '*' exp
                        { write_exp_elt_opcode (BINOP_MUL); }
        ;

exp     :       exp '/' exp
                        { write_exp_elt_opcode (BINOP_DIV); }
        ;

exp     :       exp '%' exp
                        { write_exp_elt_opcode (BINOP_REM); }
        ;

exp     :       exp '+' exp
                        { write_exp_elt_opcode (BINOP_ADD); }
        ;

exp     :       exp '-' exp
                        { write_exp_elt_opcode (BINOP_SUB); }
        ;

exp     :       exp LSH exp
                        { write_exp_elt_opcode (BINOP_LSH); }
        ;

exp     :       exp RSH exp
                        { write_exp_elt_opcode (BINOP_RSH); }
        ;

exp     :       exp EQUAL exp
                        { write_exp_elt_opcode (BINOP_EQUAL); }
        ;

exp     :       exp NOTEQUAL exp
                        { write_exp_elt_opcode (BINOP_NOTEQUAL); }
        ;

exp     :       exp LEQ exp
                        { write_exp_elt_opcode (BINOP_LEQ); }
        ;

exp     :       exp GEQ exp
                        { write_exp_elt_opcode (BINOP_GEQ); }
        ;

exp     :       exp '<' exp
                        { write_exp_elt_opcode (BINOP_LESS); }
        ;

exp     :       exp '>' exp
                        { write_exp_elt_opcode (BINOP_GTR); }
        ;

exp     :       exp '&' exp
                        { write_exp_elt_opcode (BINOP_BITWISE_AND); }
        ;

exp     :       exp '^' exp
                        { write_exp_elt_opcode (BINOP_BITWISE_XOR); }
        ;

exp     :       exp '|' exp
                        { write_exp_elt_opcode (BINOP_BITWISE_IOR); }
        ;

exp     :       exp ANDAND exp
                        { write_exp_elt_opcode (BINOP_LOGICAL_AND); }
        ;

exp     :       exp OROR exp
                        { write_exp_elt_opcode (BINOP_LOGICAL_OR); }
        ;

exp     :       exp '?' exp ':' exp     %prec '?'
                        { write_exp_elt_opcode (TERNOP_COND); }
        ;
                          
exp     :       exp '=' exp
                        { write_exp_elt_opcode (BINOP_ASSIGN); }
        ;

exp     :       exp ASSIGN_MODIFY exp
                        { write_exp_elt_opcode (BINOP_ASSIGN_MODIFY);
                          write_exp_elt_opcode ($2);
                          write_exp_elt_opcode (BINOP_ASSIGN_MODIFY); }
        ;

exp     :       INT
                        { write_exp_elt_opcode (OP_LONG);
                          write_exp_elt_type ($1.type);
                          write_exp_elt_longcst ((LONGEST)($1.val));
                          write_exp_elt_opcode (OP_LONG); }
        ;

exp     :       CHAR
                        {
                          struct stoken_vector vec;
                          vec.len = 1;
                          vec.tokens = &$1;
                          write_exp_string_vector ($1.type, &vec);
                        }
        ;

exp     :       NAME_OR_INT
                        { YYSTYPE val;
                          parse_number ($1.stoken.ptr, $1.stoken.length, 0, &val);
                          write_exp_elt_opcode (OP_LONG);
                          write_exp_elt_type (val.typed_val_int.type);
                          write_exp_elt_longcst ((LONGEST)val.typed_val_int.val);
                          write_exp_elt_opcode (OP_LONG);
                        }
        ;


exp     :       FLOAT
                        { write_exp_elt_opcode (OP_DOUBLE);
                          write_exp_elt_type ($1.type);
                          write_exp_elt_dblcst ($1.dval);
                          write_exp_elt_opcode (OP_DOUBLE); }
        ;

exp     :       DECFLOAT
                        { write_exp_elt_opcode (OP_DECFLOAT);
                          write_exp_elt_type ($1.type);
                          write_exp_elt_decfloatcst ($1.val);
                          write_exp_elt_opcode (OP_DECFLOAT); }
        ;

exp     :       variable
        ;

exp     :       VARIABLE
                        /* Already written by write_dollar_variable. */
        ;

exp     :       SIZEOF '(' type ')'     %prec UNARY
                        { write_exp_elt_opcode (OP_LONG);
                          write_exp_elt_type (parse_type->builtin_int);
                          CHECK_TYPEDEF ($3);
                          write_exp_elt_longcst ((LONGEST) TYPE_LENGTH ($3));
                          write_exp_elt_opcode (OP_LONG); }
        ;

string_exp:
                STRING
                        {
                          /* We copy the string here, and not in the
                             lexer, to guarantee that we do not leak a
                             string.  Note that we follow the
                             NUL-termination convention of the
                             lexer.  */
                          struct typed_stoken *vec = XNEW (struct typed_stoken);
                          $$.len = 1;
                          $$.tokens = vec;

                          vec->type = $1.type;
                          vec->length = $1.length;
                          vec->ptr = malloc ($1.length + 1);
                          memcpy (vec->ptr, $1.ptr, $1.length + 1);
                        }

        |       string_exp STRING
                        {
                          /* Note that we NUL-terminate here, but just
                             for convenience.  */
                          char *p;
                          ++$$.len;
                          $$.tokens = realloc ($$.tokens,
                                               $$.len * sizeof (struct typed_stoken));

                          p = malloc ($2.length + 1);
                          memcpy (p, $2.ptr, $2.length + 1);

                          $$.tokens[$$.len - 1].type = $2.type;
                          $$.tokens[$$.len - 1].length = $2.length;
                          $$.tokens[$$.len - 1].ptr = p;
                        }
                ;

exp     :       string_exp
                        {
                          int i;
                          enum c_string_type type = C_STRING;

                          for (i = 0; i < $1.len; ++i)
                            {
                              switch ($1.tokens[i].type)
                                {
                                case C_STRING:
                                  break;
                                case C_WIDE_STRING:
                                case C_STRING_16:
                                case C_STRING_32:
                                  if (type != C_STRING
                                      && type != $1.tokens[i].type)
                                    error ("Undefined string concatenation.");
                                  type = $1.tokens[i].type;
                                  break;
                                default:
                                  /* internal error */
                                  internal_error (__FILE__, __LINE__,
                                                  "unrecognized type in string concatenation");
                                }
                            }

                          write_exp_string_vector (type, &$1);
                          for (i = 0; i < $1.len; ++i)
                            free ($1.tokens[i].ptr);
                          free ($1.tokens);
                        }
        ;

/* C++.  */
exp     :       TRUEKEYWORD    
                        { write_exp_elt_opcode (OP_LONG);
                          write_exp_elt_type (parse_type->builtin_bool);
                          write_exp_elt_longcst ((LONGEST) 1);
                          write_exp_elt_opcode (OP_LONG); }
        ;

exp     :       FALSEKEYWORD   
                        { write_exp_elt_opcode (OP_LONG);
                          write_exp_elt_type (parse_type->builtin_bool);
                          write_exp_elt_longcst ((LONGEST) 0);
                          write_exp_elt_opcode (OP_LONG); }
        ;

/* end of C++.  */

block   :       BLOCKNAME
                        {
                          if ($1.sym)
                            $$ = SYMBOL_BLOCK_VALUE ($1.sym);
                          else
                            error ("No file or function \"%s\".",
                                   copy_name ($1.stoken));
                        }
        |       FILENAME
                        {
                          $$ = $1;
                        }
        ;

block   :       block COLONCOLON name
                        { struct symbol *tem
                            = lookup_symbol (copy_name ($3), $1,
                                             VAR_DOMAIN, (int *) NULL);
                          if (!tem || SYMBOL_CLASS (tem) != LOC_BLOCK)
                            error ("No function \"%s\" in specified context.",
                                   copy_name ($3));
                          $$ = SYMBOL_BLOCK_VALUE (tem); }
        ;

variable:       block COLONCOLON name
                        { struct symbol *sym;
                          sym = lookup_symbol (copy_name ($3), $1,
                                               VAR_DOMAIN, (int *) NULL);
                          if (sym == 0)
                            error ("No symbol \"%s\" in specified context.",
                                   copy_name ($3));

                          write_exp_elt_opcode (OP_VAR_VALUE);
                          /* block_found is set by lookup_symbol.  */
                          write_exp_elt_block (block_found);
                          write_exp_elt_sym (sym);
                          write_exp_elt_opcode (OP_VAR_VALUE); }
        ;

qualified_name: typebase COLONCOLON name
                        {
                          struct type *type = $1;
                          CHECK_TYPEDEF (type);
                          if (TYPE_CODE (type) != TYPE_CODE_STRUCT
                              && TYPE_CODE (type) != TYPE_CODE_UNION
                              && TYPE_CODE (type) != TYPE_CODE_NAMESPACE)
                            error ("`%s' is not defined as an aggregate type.",
                                   TYPE_NAME (type));

                          write_exp_elt_opcode (OP_SCOPE);
                          write_exp_elt_type (type);
                          write_exp_string ($3);
                          write_exp_elt_opcode (OP_SCOPE);
                        }
        |       typebase COLONCOLON '~' name
                        {
                          struct type *type = $1;
                          struct stoken tmp_token;
                          CHECK_TYPEDEF (type);
                          if (TYPE_CODE (type) != TYPE_CODE_STRUCT
                              && TYPE_CODE (type) != TYPE_CODE_UNION
                              && TYPE_CODE (type) != TYPE_CODE_NAMESPACE)
                            error ("`%s' is not defined as an aggregate type.",
                                   TYPE_NAME (type));

                          tmp_token.ptr = (char*) alloca ($4.length + 2);
                          tmp_token.length = $4.length + 1;
                          tmp_token.ptr[0] = '~';
                          memcpy (tmp_token.ptr+1, $4.ptr, $4.length);
                          tmp_token.ptr[tmp_token.length] = 0;

                          /* Check for valid destructor name.  */
                          destructor_name_p (tmp_token.ptr, type);
                          write_exp_elt_opcode (OP_SCOPE);
                          write_exp_elt_type (type);
                          write_exp_string (tmp_token);
                          write_exp_elt_opcode (OP_SCOPE);
                        }
        ;

variable:       qualified_name
        |       COLONCOLON name
                        {
                          char *name = copy_name ($2);
                          struct symbol *sym;
                          struct minimal_symbol *msymbol;

                          sym =
                            lookup_symbol (name, (const struct block *) NULL,
                                           VAR_DOMAIN, (int *) NULL);
                          if (sym)
                            {
                              write_exp_elt_opcode (OP_VAR_VALUE);
                              write_exp_elt_block (NULL);
                              write_exp_elt_sym (sym);
                              write_exp_elt_opcode (OP_VAR_VALUE);
                              break;
                            }

                          msymbol = lookup_minimal_symbol (name, NULL, NULL);
                          if (msymbol != NULL)
                            write_exp_msymbol (msymbol);
                          else if (!have_full_symbols () && !have_partial_symbols ())
                            error ("No symbol table is loaded.  Use the \"file\" command.");
                          else
                            error ("No symbol \"%s\" in current context.", name);
                        }
        ;

variable:       name_not_typename
                        { struct symbol *sym = $1.sym;

                          if (sym)
                            {
                              if (symbol_read_needs_frame (sym))
                                {
                                  if (innermost_block == 0
                                      || contained_in (block_found, 
                                                       innermost_block))
                                    innermost_block = block_found;
                                }

                              write_exp_elt_opcode (OP_VAR_VALUE);
                              /* We want to use the selected frame, not
                                 another more inner frame which happens to
                                 be in the same block.  */
                              write_exp_elt_block (NULL);
                              write_exp_elt_sym (sym);
                              write_exp_elt_opcode (OP_VAR_VALUE);
                            }
                          else if ($1.is_a_field_of_this)
                            {
                              /* C++: it hangs off of `this'.  Must
                                 not inadvertently convert from a method call
                                 to data ref.  */
                              if (innermost_block == 0
                                  || contained_in (block_found,
                                                   innermost_block))
                                innermost_block = block_found;
                              write_exp_elt_opcode (OP_THIS);
                              write_exp_elt_opcode (OP_THIS);
                              write_exp_elt_opcode (STRUCTOP_PTR);
                              write_exp_string ($1.stoken);
                              write_exp_elt_opcode (STRUCTOP_PTR);
                            }
                          else
                            {
                              struct minimal_symbol *msymbol;
                              char *arg = copy_name ($1.stoken);

                              msymbol =
                                lookup_minimal_symbol (arg, NULL, NULL);
                              if (msymbol != NULL)
                                write_exp_msymbol (msymbol);
                              else if (!have_full_symbols () && !have_partial_symbols ())
                                error ("No symbol table is loaded.  Use the \"file\" command.");
                              else
                                error ("No symbol \"%s\" in current context.",
                                       copy_name ($1.stoken));
                            }
                        }
        ;

space_identifier : '@' NAME
                { push_type_address_space (copy_name ($2.stoken));
                  push_type (tp_space_identifier);
                }
        ;

const_or_volatile: const_or_volatile_noopt
        |
        ;

cv_with_space_id : const_or_volatile space_identifier const_or_volatile
        ;

const_or_volatile_or_space_identifier_noopt: cv_with_space_id
        | const_or_volatile_noopt 
        ;

const_or_volatile_or_space_identifier: 
                const_or_volatile_or_space_identifier_noopt
        |
        ;

abs_decl:       '*'
                        { push_type (tp_pointer); $$ = 0; }
        |       '*' abs_decl
                        { push_type (tp_pointer); $$ = $2; }
        |       '&'
                        { push_type (tp_reference); $$ = 0; }
        |       '&' abs_decl
                        { push_type (tp_reference); $$ = $2; }
        |       direct_abs_decl
        ;

direct_abs_decl: '(' abs_decl ')'
                        { $$ = $2; }
        |       direct_abs_decl array_mod
                        {
                          push_type_int ($2);
                          push_type (tp_array);
                        }
        |       array_mod
                        {
                          push_type_int ($1);
                          push_type (tp_array);
                          $$ = 0;
                        }

        |       direct_abs_decl func_mod
                        { push_type (tp_function); }
        |       func_mod
                        { push_type (tp_function); }
        ;

array_mod:      '[' ']'
                        { $$ = -1; }
        |       '[' INT ']'
                        { $$ = $2.val; }
        ;

func_mod:       '(' ')'
                        { $$ = 0; }
        |       '(' nonempty_typelist ')'
                        { free ($2); $$ = 0; }
        ;

/* We used to try to recognize pointer to member types here, but
   that didn't work (shift/reduce conflicts meant that these rules never
   got executed).  The problem is that
     int (foo::bar::baz::bizzle)
   is a function type but
     int (foo::bar::baz::bizzle::*)
   is a pointer to member type.  Stroustrup loses again!  */

type    :       ptype
        ;

typebase  /* Implements (approximately): (type-qualifier)* type-specifier */
        :       TYPENAME
                        { $$ = $1.type; }
        |       INT_KEYWORD
                        { $$ = parse_type->builtin_int; }
        |       LONG
                        { $$ = parse_type->builtin_long; }
        |       SHORT
                        { $$ = parse_type->builtin_short; }
        |       LONG INT_KEYWORD
                        { $$ = parse_type->builtin_long; }
        |       LONG SIGNED_KEYWORD INT_KEYWORD
                        { $$ = parse_type->builtin_long; }
        |       LONG SIGNED_KEYWORD
                        { $$ = parse_type->builtin_long; }
        |       SIGNED_KEYWORD LONG INT_KEYWORD
                        { $$ = parse_type->builtin_long; }
        |       UNSIGNED LONG INT_KEYWORD
                        { $$ = parse_type->builtin_unsigned_long; }
        |       LONG UNSIGNED INT_KEYWORD
                        { $$ = parse_type->builtin_unsigned_long; }
        |       LONG UNSIGNED
                        { $$ = parse_type->builtin_unsigned_long; }
        |       LONG LONG
                        { $$ = parse_type->builtin_long_long; }
        |       LONG LONG INT_KEYWORD
                        { $$ = parse_type->builtin_long_long; }
        |       LONG LONG SIGNED_KEYWORD INT_KEYWORD
                        { $$ = parse_type->builtin_long_long; }
        |       LONG LONG SIGNED_KEYWORD
                        { $$ = parse_type->builtin_long_long; }
        |       SIGNED_KEYWORD LONG LONG
                        { $$ = parse_type->builtin_long_long; }
        |       SIGNED_KEYWORD LONG LONG INT_KEYWORD
                        { $$ = parse_type->builtin_long_long; }
        |       UNSIGNED LONG LONG
                        { $$ = parse_type->builtin_unsigned_long_long; }
        |       UNSIGNED LONG LONG INT_KEYWORD
                        { $$ = parse_type->builtin_unsigned_long_long; }
        |       LONG LONG UNSIGNED
                        { $$ = parse_type->builtin_unsigned_long_long; }
        |       LONG LONG UNSIGNED INT_KEYWORD
                        { $$ = parse_type->builtin_unsigned_long_long; }
        |       SHORT INT_KEYWORD
                        { $$ = parse_type->builtin_short; }
        |       SHORT SIGNED_KEYWORD INT_KEYWORD
                        { $$ = parse_type->builtin_short; }
        |       SHORT SIGNED_KEYWORD
                        { $$ = parse_type->builtin_short; }
        |       UNSIGNED SHORT INT_KEYWORD
                        { $$ = parse_type->builtin_unsigned_short; }
        |       SHORT UNSIGNED 
                        { $$ = parse_type->builtin_unsigned_short; }
        |       SHORT UNSIGNED INT_KEYWORD
                        { $$ = parse_type->builtin_unsigned_short; }
        |       DOUBLE_KEYWORD
                        { $$ = parse_type->builtin_double; }
        |       LONG DOUBLE_KEYWORD
                        { $$ = parse_type->builtin_long_double; }
        |       STRUCT name
                        { $$ = lookup_struct (copy_name ($2),
                                              expression_context_block); }
        |       CLASS name
                        { $$ = lookup_struct (copy_name ($2),
                                              expression_context_block); }
        |       UNION name
                        { $$ = lookup_union (copy_name ($2),
                                             expression_context_block); }
        |       ENUM name
                        { $$ = lookup_enum (copy_name ($2),
                                            expression_context_block); }
        |       UNSIGNED typename
                        { $$ = lookup_unsigned_typename (parse_language,
                                                         parse_gdbarch,
                                                         TYPE_NAME($2.type)); }
        |       UNSIGNED
                        { $$ = parse_type->builtin_unsigned_int; }
        |       SIGNED_KEYWORD typename
                        { $$ = lookup_signed_typename (parse_language,
                                                       parse_gdbarch,
                                                       TYPE_NAME($2.type)); }
        |       SIGNED_KEYWORD
                        { $$ = parse_type->builtin_int; }
                /* It appears that this rule for templates is never
                   reduced; template recognition happens by lookahead
                   in the token processing code in yylex. */         
        |       TEMPLATE name '<' type '>'
                        { $$ = lookup_template_type(copy_name($2), $4,
                                                    expression_context_block);
                        }
        | const_or_volatile_or_space_identifier_noopt typebase 
                        { $$ = follow_types ($2); }
        | typebase const_or_volatile_or_space_identifier_noopt 
                        { $$ = follow_types ($1); }
        | qualified_type
        ;

/* FIXME: carlton/2003-09-25: This next bit leads to lots of
   reduce-reduce conflicts, because the parser doesn't know whether or
   not to use qualified_name or qualified_type: the rules are
   identical.  If the parser is parsing 'A::B::x', then, when it sees
   the second '::', it knows that the expression to the left of it has
   to be a type, so it uses qualified_type.  But if it is parsing just
   'A::B', then it doesn't have any way of knowing which rule to use,
   so there's a reduce-reduce conflict; it picks qualified_name, since
   that occurs earlier in this file than qualified_type.

   There's no good way to fix this with the grammar as it stands; as
   far as I can tell, some of the problems arise from ambiguities that
   GDB introduces ('start' can be either an expression or a type), but
   some of it is inherent to the nature of C++ (you want to treat the
   input "(FOO)" fairly differently depending on whether FOO is an
   expression or a type, and if FOO is a complex expression, this can
   be hard to determine at the right time).  Fortunately, it works
   pretty well in most cases.  For example, if you do 'ptype A::B',
   where A::B is a nested type, then the parser will mistakenly
   misidentify it as an expression; but evaluate_subexp will get
   called with 'noside' set to EVAL_AVOID_SIDE_EFFECTS, and everything
   will work out anyways.  But there are situations where the parser
   will get confused: the most common one that I've run into is when
   you want to do

     print *((A::B *) x)"

   where the parser doesn't realize that A::B has to be a type until
   it hits the first right paren, at which point it's too late.  (The
   workaround is to type "print *(('A::B' *) x)" instead.)  (And
   another solution is to fix our symbol-handling code so that the
   user never wants to type something like that in the first place,
   because we get all the types right without the user's help!)

   Perhaps we could fix this by making the lexer smarter.  Some of
   this functionality used to be in the lexer, but in a way that
   worked even less well than the current solution: that attempt
   involved having the parser sometimes handle '::' and having the
   lexer sometimes handle it, and without a clear division of
   responsibility, it quickly degenerated into a big mess.  Probably
   the eventual correct solution will give more of a role to the lexer
   (ideally via code that is shared between the lexer and
   decode_line_1), but I'm not holding my breath waiting for somebody
   to get around to cleaning this up...  */

qualified_type: typebase COLONCOLON name
                {
                  struct type *type = $1;
                  struct type *new_type;
                  char *ncopy = alloca ($3.length + 1);

                  memcpy (ncopy, $3.ptr, $3.length);
                  ncopy[$3.length] = '\0';

                  if (TYPE_CODE (type) != TYPE_CODE_STRUCT
                      && TYPE_CODE (type) != TYPE_CODE_UNION
                      && TYPE_CODE (type) != TYPE_CODE_NAMESPACE)
                    error ("`%s' is not defined as an aggregate type.",
                           TYPE_NAME (type));

                  new_type = cp_lookup_nested_type (type, ncopy,
                                                    expression_context_block);
                  if (new_type == NULL)
                    error ("No type \"%s\" within class or namespace \"%s\".",
                           ncopy, TYPE_NAME (type));
                  
                  $$ = new_type;
                }
        ;

typename:       TYPENAME
        |       INT_KEYWORD
                {
                  $$.stoken.ptr = "int";
                  $$.stoken.length = 3;
                  $$.type = parse_type->builtin_int;
                }
        |       LONG
                {
                  $$.stoken.ptr = "long";
                  $$.stoken.length = 4;
                  $$.type = parse_type->builtin_long;
                }
        |       SHORT
                {
                  $$.stoken.ptr = "short";
                  $$.stoken.length = 5;
                  $$.type = parse_type->builtin_short;
                }
        ;

nonempty_typelist
        :       type
                { $$ = (struct type **) malloc (sizeof (struct type *) * 2);
                  $<ivec>$[0] = 1;      /* Number of types in vector */
                  $$[1] = $1;
                }
        |       nonempty_typelist ',' type
                { int len = sizeof (struct type *) * (++($<ivec>1[0]) + 1);
                  $$ = (struct type **) realloc ((char *) $1, len);
                  $$[$<ivec>$[0]] = $3;
                }
        ;

ptype   :       typebase
        |       ptype const_or_volatile_or_space_identifier abs_decl const_or_volatile_or_space_identifier
                { $$ = follow_types ($1); }
        ;

const_and_volatile:     CONST_KEYWORD VOLATILE_KEYWORD
        |               VOLATILE_KEYWORD CONST_KEYWORD
        ;

const_or_volatile_noopt:        const_and_volatile 
                        { push_type (tp_const);
                          push_type (tp_volatile); 
                        }
        |               CONST_KEYWORD
                        { push_type (tp_const); }
        |               VOLATILE_KEYWORD
                        { push_type (tp_volatile); }
        ;

name    :       NAME { $$ = $1.stoken; }
        |       BLOCKNAME { $$ = $1.stoken; }
        |       TYPENAME { $$ = $1.stoken; }
        |       NAME_OR_INT  { $$ = $1.stoken; }
        ;

name_not_typename :     NAME
        |       BLOCKNAME
/* These would be useful if name_not_typename was useful, but it is just
   a fake for "variable", so these cause reduce/reduce conflicts because
   the parser can't tell whether NAME_OR_INT is a name_not_typename (=variable,
   =exp) or just an exp.  If name_not_typename was ever used in an lvalue
   context where only a name could occur, this might be useful.
        |       NAME_OR_INT
 */
        ;

%%

/* Take care of parsing a number (anything that starts with a digit).
   Set yylval and return the token type; update lexptr.
   LEN is the number of characters in it.  */

/*** Needs some error checking for the float case ***/

static int
parse_number (char *p, int len, int parsed_float, YYSTYPE *putithere)
{
  /* FIXME: Shouldn't these be unsigned?  We don't deal with negative values
     here, and we do kind of silly things like cast to unsigned.  */
  LONGEST n = 0;
  LONGEST prevn = 0;
  ULONGEST un;

  int i = 0;
  int c;
  int base = input_radix;
  int unsigned_p = 0;

  /* Number of "L" suffixes encountered.  */
  int long_p = 0;

  /* We have found a "L" or "U" suffix.  */
  int found_suffix = 0;

  ULONGEST high_bit;
  struct type *signed_type;
  struct type *unsigned_type;

  if (parsed_float)
    {
      /* It's a float since it contains a point or an exponent.  */
      char *s;
      int num;  /* number of tokens scanned by scanf */
      char saved_char;

      /* If it ends at "df", "dd" or "dl", take it as type of decimal floating
         point.  Return DECFLOAT.  */

      if (len >= 2 && p[len - 2] == 'd' && p[len - 1] == 'f')
        {
          p[len - 2] = '\0';
          putithere->typed_val_decfloat.type
            = parse_type->builtin_decfloat;
          decimal_from_string (putithere->typed_val_decfloat.val, 4,
                               gdbarch_byte_order (parse_gdbarch), p);
          p[len - 2] = 'd';
          return DECFLOAT;
        }

      if (len >= 2 && p[len - 2] == 'd' && p[len - 1] == 'd')
        {
          p[len - 2] = '\0';
          putithere->typed_val_decfloat.type
            = parse_type->builtin_decdouble;
          decimal_from_string (putithere->typed_val_decfloat.val, 8,
                               gdbarch_byte_order (parse_gdbarch), p);
          p[len - 2] = 'd';
          return DECFLOAT;
        }

      if (len >= 2 && p[len - 2] == 'd' && p[len - 1] == 'l')
        {
          p[len - 2] = '\0';
          putithere->typed_val_decfloat.type
            = parse_type->builtin_declong;
          decimal_from_string (putithere->typed_val_decfloat.val, 16,
                               gdbarch_byte_order (parse_gdbarch), p);
          p[len - 2] = 'd';
          return DECFLOAT;
        }

      s = malloc (len);
      saved_char = p[len];
      p[len] = 0;       /* null-terminate the token */
      num = sscanf (p, "%" DOUBLEST_SCAN_FORMAT "%s",
                    &putithere->typed_val_float.dval, s);
      p[len] = saved_char;      /* restore the input stream */

      if (num == 1)
        putithere->typed_val_float.type = 
          parse_type->builtin_double;

      if (num == 2 )
        {
          /* See if it has any float suffix: 'f' for float, 'l' for long 
             double.  */
          if (!strcasecmp (s, "f"))
            putithere->typed_val_float.type = 
              parse_type->builtin_float;
          else if (!strcasecmp (s, "l"))
            putithere->typed_val_float.type = 
              parse_type->builtin_long_double;
          else
            {
              free (s);
              return ERROR;
            }
        }

      free (s);
      return FLOAT;
    }

  /* Handle base-switching prefixes 0x, 0t, 0d, 0 */
  if (p[0] == '0')
    switch (p[1])
      {
      case 'x':
      case 'X':
        if (len >= 3)
          {
            p += 2;
            base = 16;
            len -= 2;
          }
        break;

      case 't':
      case 'T':
      case 'd':
      case 'D':
        if (len >= 3)
          {
            p += 2;
            base = 10;
            len -= 2;
          }
        break;

      default:
        base = 8;
        break;
      }

  while (len-- > 0)
    {
      c = *p++;
      if (c >= 'A' && c <= 'Z')
        c += 'a' - 'A';
      if (c != 'l' && c != 'u')
        n *= base;
      if (c >= '0' && c <= '9')
        {
          if (found_suffix)
            return ERROR;
          n += i = c - '0';
        }
      else
        {
          if (base > 10 && c >= 'a' && c <= 'f')
            {
              if (found_suffix)
                return ERROR;
              n += i = c - 'a' + 10;
            }
          else if (c == 'l')
            {
              ++long_p;
              found_suffix = 1;
            }
          else if (c == 'u')
            {
              unsigned_p = 1;
              found_suffix = 1;
            }
          else
            return ERROR;       /* Char not a digit */
        }
      if (i >= base)
        return ERROR;           /* Invalid digit in this base */

      /* Portably test for overflow (only works for nonzero values, so make
         a second check for zero).  FIXME: Can't we just make n and prevn
         unsigned and avoid this?  */
      if (c != 'l' && c != 'u' && (prevn >= n) && n != 0)
        unsigned_p = 1;         /* Try something unsigned */

      /* Portably test for unsigned overflow.
         FIXME: This check is wrong; for example it doesn't find overflow
         on 0x123456789 when LONGEST is 32 bits.  */
      if (c != 'l' && c != 'u' && n != 0)
        {       
          if ((unsigned_p && (ULONGEST) prevn >= (ULONGEST) n))
            error ("Numeric constant too large.");
        }
      prevn = n;
    }

  /* An integer constant is an int, a long, or a long long.  An L
     suffix forces it to be long; an LL suffix forces it to be long
     long.  If not forced to a larger size, it gets the first type of
     the above that it fits in.  To figure out whether it fits, we
     shift it right and see whether anything remains.  Note that we
     can't shift sizeof (LONGEST) * HOST_CHAR_BIT bits or more in one
     operation, because many compilers will warn about such a shift
     (which always produces a zero result).  Sometimes gdbarch_int_bit
     or gdbarch_long_bit will be that big, sometimes not.  To deal with
     the case where it is we just always shift the value more than
     once, with fewer bits each time.  */

  un = (ULONGEST)n >> 2;
  if (long_p == 0
      && (un >> (gdbarch_int_bit (parse_gdbarch) - 2)) == 0)
    {
      high_bit = ((ULONGEST)1) << (gdbarch_int_bit (parse_gdbarch) - 1);

      /* A large decimal (not hex or octal) constant (between INT_MAX
         and UINT_MAX) is a long or unsigned long, according to ANSI,
         never an unsigned int, but this code treats it as unsigned
         int.  This probably should be fixed.  GCC gives a warning on
         such constants.  */

      unsigned_type = parse_type->builtin_unsigned_int;
      signed_type = parse_type->builtin_int;
    }
  else if (long_p <= 1
           && (un >> (gdbarch_long_bit (parse_gdbarch) - 2)) == 0)
    {
      high_bit = ((ULONGEST)1) << (gdbarch_long_bit (parse_gdbarch) - 1);
      unsigned_type = parse_type->builtin_unsigned_long;
      signed_type = parse_type->builtin_long;
    }
  else
    {
      int shift;
      if (sizeof (ULONGEST) * HOST_CHAR_BIT 
          < gdbarch_long_long_bit (parse_gdbarch))
        /* A long long does not fit in a LONGEST.  */
        shift = (sizeof (ULONGEST) * HOST_CHAR_BIT - 1);
      else
        shift = (gdbarch_long_long_bit (parse_gdbarch) - 1);
      high_bit = (ULONGEST) 1 << shift;
      unsigned_type = parse_type->builtin_unsigned_long_long;
      signed_type = parse_type->builtin_long_long;
    }

   putithere->typed_val_int.val = n;

   /* If the high bit of the worked out type is set then this number
      has to be unsigned. */

   if (unsigned_p || (n & high_bit)) 
     {
       putithere->typed_val_int.type = unsigned_type;
     }
   else 
     {
       putithere->typed_val_int.type = signed_type;
     }

   return INT;
}

/* Temporary obstack used for holding strings.  */
static struct obstack tempbuf;
static int tempbuf_init;

/* Parse a C escape sequence.  The initial backslash of the sequence
   is at (*PTR)[-1].  *PTR will be updated to point to just after the
   last character of the sequence.  If OUTPUT is not NULL, the
   translated form of the escape sequence will be written there.  If
   OUTPUT is NULL, no output is written and the call will only affect
   *PTR.  If an escape sequence is expressed in target bytes, then the
   entire sequence will simply be copied to OUTPUT.  Return 1 if any
   character was emitted, 0 otherwise.  */

int
c_parse_escape (char **ptr, struct obstack *output)
{
  char *tokptr = *ptr;
  int result = 1;

  /* Some escape sequences undergo character set conversion.  Those we
     translate here.  */
  switch (*tokptr)
    {
      /* Hex escapes do not undergo character set conversion, so keep
         the escape sequence for later.  */
    case 'x':
      if (output)
        obstack_grow_str (output, "\\x");
      ++tokptr;
      if (!isxdigit (*tokptr))
        error (_("\\x escape without a following hex digit"));
      while (isxdigit (*tokptr))
        {
          if (output)
            obstack_1grow (output, *tokptr);
          ++tokptr;
        }
      break;

      /* Octal escapes do not undergo character set conversion, so
         keep the escape sequence for later.  */
    case '0':
    case '1':
    case '2':
    case '3':
    case '4':
    case '5':
    case '6':
    case '7':
      {
        int i;
        if (output)
          obstack_grow_str (output, "\\");
        for (i = 0;
             i < 3 && isdigit (*tokptr) && *tokptr != '8' && *tokptr != '9';
             ++i)
          {
            if (output)
              obstack_1grow (output, *tokptr);
            ++tokptr;
          }
      }
      break;

      /* We handle UCNs later.  We could handle them here, but that
         would mean a spurious error in the case where the UCN could
         be converted to the target charset but not the host
         charset.  */
    case 'u':
    case 'U':
      {
        char c = *tokptr;
        int i, len = c == 'U' ? 8 : 4;
        if (output)
          {
            obstack_1grow (output, '\\');
            obstack_1grow (output, *tokptr);
          }
        ++tokptr;
        if (!isxdigit (*tokptr))
          error (_("\\%c escape without a following hex digit"), c);
        for (i = 0; i < len && isxdigit (*tokptr); ++i)
          {
            if (output)
              obstack_1grow (output, *tokptr);
            ++tokptr;
          }
      }
      break;

      /* We must pass backslash through so that it does not
         cause quoting during the second expansion.  */
    case '\\':
      if (output)
        obstack_grow_str (output, "\\\\");
      ++tokptr;
      break;

      /* Escapes which undergo conversion.  */
    case 'a':
      if (output)
        obstack_1grow (output, '\a');
      ++tokptr;
      break;
    case 'b':
      if (output)
        obstack_1grow (output, '\b');
      ++tokptr;
      break;
    case 'f':
      if (output)
        obstack_1grow (output, '\f');
      ++tokptr;
      break;
    case 'n':
      if (output)
        obstack_1grow (output, '\n');
      ++tokptr;
      break;
    case 'r':
      if (output)
        obstack_1grow (output, '\r');
      ++tokptr;
      break;
    case 't':
      if (output)
        obstack_1grow (output, '\t');
      ++tokptr;
      break;
    case 'v':
      if (output)
        obstack_1grow (output, '\v');
      ++tokptr;
      break;

      /* GCC extension.  */
    case 'e':
      if (output)
        obstack_1grow (output, HOST_ESCAPE_CHAR);
      ++tokptr;
      break;

      /* Backslash-newline expands to nothing at all.  */
    case '\n':
      ++tokptr;
      result = 0;
      break;

      /* A few escapes just expand to the character itself.  */
    case '\'':
    case '\"':
    case '?':
      /* GCC extensions.  */
    case '(':
    case '{':
    case '[':
    case '%':
      /* Unrecognized escapes turn into the character itself.  */
    default:
      if (output)
        obstack_1grow (output, *tokptr);
      ++tokptr;
      break;
    }
  *ptr = tokptr;
  return result;
}

/* Parse a string or character literal from TOKPTR.  The string or
   character may be wide or unicode.  *OUTPTR is set to just after the
   end of the literal in the input string.  The resulting token is
   stored in VALUE.  This returns a token value, either STRING or
   CHAR, depending on what was parsed.  *HOST_CHARS is set to the
   number of host characters in the literal.  */
static int
parse_string_or_char (char *tokptr, char **outptr, struct typed_stoken *value,
                      int *host_chars)
{
  int quote, i;
  enum c_string_type type;

  /* Build the gdb internal form of the input string in tempbuf.  Note
     that the buffer is null byte terminated *only* for the
     convenience of debugging gdb itself and printing the buffer
     contents when the buffer contains no embedded nulls.  Gdb does
     not depend upon the buffer being null byte terminated, it uses
     the length string instead.  This allows gdb to handle C strings
     (as well as strings in other languages) with embedded null
     bytes */

  if (!tempbuf_init)
    tempbuf_init = 1;
  else
    obstack_free (&tempbuf, NULL);
  obstack_init (&tempbuf);

  /* Record the string type.  */
  if (*tokptr == 'L')
    {
      type = C_WIDE_STRING;
      ++tokptr;
    }
  else if (*tokptr == 'u')
    {
      type = C_STRING_16;
      ++tokptr;
    }
  else if (*tokptr == 'U')
    {
      type = C_STRING_32;
      ++tokptr;
    }
  else
    type = C_STRING;

  /* Skip the quote.  */
  quote = *tokptr;
  if (quote == '\'')
    type |= C_CHAR;
  ++tokptr;

  *host_chars = 0;

  while (*tokptr)
    {
      char c = *tokptr;
      if (c == '\\')
        {
          ++tokptr;
          *host_chars += c_parse_escape (&tokptr, &tempbuf);
        }
      else if (c == quote)
        break;
      else
        {
          obstack_1grow (&tempbuf, c);
          ++tokptr;
          /* FIXME: this does the wrong thing with multi-byte host
             characters.  We could use mbrlen here, but that would
             make "set host-charset" a bit less useful.  */
          ++*host_chars;
        }
    }

  if (*tokptr != quote)
    {
      if (quote == '"')
        error ("Unterminated string in expression.");
      else
        error ("Unmatched single quote.");
    }
  ++tokptr;

  value->type = type;
  value->ptr = obstack_base (&tempbuf);
  value->length = obstack_object_size (&tempbuf);

  *outptr = tokptr;

  return quote == '"' ? STRING : CHAR;
}

struct token
{
  char *operator;
  int token;
  enum exp_opcode opcode;
  int cxx_only;
};

static const struct token tokentab3[] =
  {
    {">>=", ASSIGN_MODIFY, BINOP_RSH, 0},
    {"<<=", ASSIGN_MODIFY, BINOP_LSH, 0},
    {"->*", ARROW_STAR, BINOP_END, 1}
  };

static const struct token tokentab2[] =
  {
    {"+=", ASSIGN_MODIFY, BINOP_ADD, 0},
    {"-=", ASSIGN_MODIFY, BINOP_SUB, 0},
    {"*=", ASSIGN_MODIFY, BINOP_MUL, 0},
    {"/=", ASSIGN_MODIFY, BINOP_DIV, 0},
    {"%=", ASSIGN_MODIFY, BINOP_REM, 0},
    {"|=", ASSIGN_MODIFY, BINOP_BITWISE_IOR, 0},
    {"&=", ASSIGN_MODIFY, BINOP_BITWISE_AND, 0},
    {"^=", ASSIGN_MODIFY, BINOP_BITWISE_XOR, 0},
    {"++", INCREMENT, BINOP_END, 0},
    {"--", DECREMENT, BINOP_END, 0},
    {"->", ARROW, BINOP_END, 0},
    {"&&", ANDAND, BINOP_END, 0},
    {"||", OROR, BINOP_END, 0},
    /* "::" is *not* only C++: gdb overrides its meaning in several
       different ways, e.g., 'filename'::func, function::variable.  */
    {"::", COLONCOLON, BINOP_END, 0},
    {"<<", LSH, BINOP_END, 0},
    {">>", RSH, BINOP_END, 0},
    {"==", EQUAL, BINOP_END, 0},
    {"!=", NOTEQUAL, BINOP_END, 0},
    {"<=", LEQ, BINOP_END, 0},
    {">=", GEQ, BINOP_END, 0},
    {".*", DOT_STAR, BINOP_END, 1}
  };

/* Identifier-like tokens.  */
static const struct token ident_tokens[] =
  {
    {"unsigned", UNSIGNED, OP_NULL, 0},
    {"template", TEMPLATE, OP_NULL, 1},
    {"volatile", VOLATILE_KEYWORD, OP_NULL, 0},
    {"struct", STRUCT, OP_NULL, 0},
    {"signed", SIGNED_KEYWORD, OP_NULL, 0},
    {"sizeof", SIZEOF, OP_NULL, 0},
    {"double", DOUBLE_KEYWORD, OP_NULL, 0},
    {"false", FALSEKEYWORD, OP_NULL, 1},
    {"class", CLASS, OP_NULL, 1},
    {"union", UNION, OP_NULL, 0},
    {"short", SHORT, OP_NULL, 0},
    {"const", CONST_KEYWORD, OP_NULL, 0},
    {"enum", ENUM, OP_NULL, 0},
    {"long", LONG, OP_NULL, 0},
    {"true", TRUEKEYWORD, OP_NULL, 1},
    {"int", INT_KEYWORD, OP_NULL, 0},

    {"and", ANDAND, BINOP_END, 1},
    {"and_eq", ASSIGN_MODIFY, BINOP_BITWISE_AND, 1},
    {"bitand", '&', OP_NULL, 1},
    {"bitor", '|', OP_NULL, 1},
    {"compl", '~', OP_NULL, 1},
    {"not", '!', OP_NULL, 1},
    {"not_eq", NOTEQUAL, BINOP_END, 1},
    {"or", OROR, BINOP_END, 1},
    {"or_eq", ASSIGN_MODIFY, BINOP_BITWISE_IOR, 1},
    {"xor", '^', OP_NULL, 1},
    {"xor_eq", ASSIGN_MODIFY, BINOP_BITWISE_XOR, 1}
  };

/* When we find that lexptr (the global var defined in parse.c) is
   pointing at a macro invocation, we expand the invocation, and call
   scan_macro_expansion to save the old lexptr here and point lexptr
   into the expanded text.  When we reach the end of that, we call
   end_macro_expansion to pop back to the value we saved here.  The
   macro expansion code promises to return only fully-expanded text,
   so we don't need to "push" more than one level.

   This is disgusting, of course.  It would be cleaner to do all macro
   expansion beforehand, and then hand that to lexptr.  But we don't
   really know where the expression ends.  Remember, in a command like

     (gdb) break *ADDRESS if CONDITION

   we evaluate ADDRESS in the scope of the current frame, but we
   evaluate CONDITION in the scope of the breakpoint's location.  So
   it's simply wrong to try to macro-expand the whole thing at once.  */
static char *macro_original_text;

/* We save all intermediate macro expansions on this obstack for the
   duration of a single parse.  The expansion text may sometimes have
   to live past the end of the expansion, due to yacc lookahead.
   Rather than try to be clever about saving the data for a single
   token, we simply keep it all and delete it after parsing has
   completed.  */
static struct obstack expansion_obstack;

static void
scan_macro_expansion (char *expansion)
{
  char *copy;

  /* We'd better not be trying to push the stack twice.  */
  gdb_assert (! macro_original_text);

  /* Copy to the obstack, and then free the intermediate
     expansion.  */
  copy = obstack_copy0 (&expansion_obstack, expansion, strlen (expansion));
  xfree (expansion);

  /* Save the old lexptr value, so we can return to it when we're done
     parsing the expanded text.  */
  macro_original_text = lexptr;
  lexptr = copy;
}


static int
scanning_macro_expansion (void)
{
  return macro_original_text != 0;
}


static void 
finished_macro_expansion (void)
{
  /* There'd better be something to pop back to.  */
  gdb_assert (macro_original_text);

  /* Pop back to the original text.  */
  lexptr = macro_original_text;
  macro_original_text = 0;
}


static void
scan_macro_cleanup (void *dummy)
{
  if (macro_original_text)
    finished_macro_expansion ();

  obstack_free (&expansion_obstack, NULL);
}


/* The scope used for macro expansion.  */
static struct macro_scope *expression_macro_scope;

/* This is set if a NAME token appeared at the very end of the input
   string, with no whitespace separating the name from the EOF.  This
   is used only when parsing to do field name completion.  */
static int saw_name_at_eof;

/* This is set if the previously-returned token was a structure
   operator -- either '.' or ARROW.  This is used only when parsing to
   do field name completion.  */
static int last_was_structop;

/* Read one token, getting characters through lexptr.  */

static int
yylex (void)
{
  int c;
  int namelen;
  unsigned int i;
  char *tokstart;
  int saw_structop = last_was_structop;
  char *copy;

  last_was_structop = 0;

 retry:

  /* Check if this is a macro invocation that we need to expand.  */
  if (! scanning_macro_expansion ())
    {
      char *expanded = macro_expand_next (&lexptr,
                                          standard_macro_lookup,
                                          expression_macro_scope);

      if (expanded)
        scan_macro_expansion (expanded);
    }

  prev_lexptr = lexptr;

  tokstart = lexptr;
  /* See if it is a special token of length 3.  */
  for (i = 0; i < sizeof tokentab3 / sizeof tokentab3[0]; i++)
    if (strncmp (tokstart, tokentab3[i].operator, 3) == 0)
      {
        if (tokentab3[i].cxx_only
            && parse_language->la_language != language_cplus)
          break;

        lexptr += 3;
        yylval.opcode = tokentab3[i].opcode;
        return tokentab3[i].token;
      }

  /* See if it is a special token of length 2.  */
  for (i = 0; i < sizeof tokentab2 / sizeof tokentab2[0]; i++)
    if (strncmp (tokstart, tokentab2[i].operator, 2) == 0)
      {
        if (tokentab2[i].cxx_only
            && parse_language->la_language != language_cplus)
          break;

        lexptr += 2;
        yylval.opcode = tokentab2[i].opcode;
        if (in_parse_field && tokentab2[i].token == ARROW)
          last_was_structop = 1;
        return tokentab2[i].token;
      }

  switch (c = *tokstart)
    {
    case 0:
      /* If we were just scanning the result of a macro expansion,
         then we need to resume scanning the original text.
         If we're parsing for field name completion, and the previous
         token allows such completion, return a COMPLETE token.
         Otherwise, we were already scanning the original text, and
         we're really done.  */
      if (scanning_macro_expansion ())
        {
          finished_macro_expansion ();
          goto retry;
        }
      else if (saw_name_at_eof)
        {
          saw_name_at_eof = 0;
          return COMPLETE;
        }
      else if (saw_structop)
        return COMPLETE;
      else
        return 0;

    case ' ':
    case '\t':
    case '\n':
      lexptr++;
      goto retry;

    case '[':
    case '(':
      paren_depth++;
      lexptr++;
      return c;

    case ']':
    case ')':
      if (paren_depth == 0)
        return 0;
      paren_depth--;
      lexptr++;
      return c;

    case ',':
      if (comma_terminates
          && paren_depth == 0
          && ! scanning_macro_expansion ())
        return 0;
      lexptr++;
      return c;

    case '.':
      /* Might be a floating point number.  */
      if (lexptr[1] < '0' || lexptr[1] > '9')
        {
          if (in_parse_field)
            last_was_structop = 1;
          goto symbol;          /* Nope, must be a symbol. */
        }
      /* FALL THRU into number case.  */

    case '0':
    case '1':
    case '2':
    case '3':
    case '4':
    case '5':
    case '6':
    case '7':
    case '8':
    case '9':
      {
        /* It's a number.  */
        int got_dot = 0, got_e = 0, toktype;
        char *p = tokstart;
        int hex = input_radix > 10;

        if (c == '0' && (p[1] == 'x' || p[1] == 'X'))
          {
            p += 2;
            hex = 1;
          }
        else if (c == '0' && (p[1]=='t' || p[1]=='T' || p[1]=='d' || p[1]=='D'))
          {
            p += 2;
            hex = 0;
          }

        for (;; ++p)
          {
            /* This test includes !hex because 'e' is a valid hex digit
               and thus does not indicate a floating point number when
               the radix is hex.  */
            if (!hex && !got_e && (*p == 'e' || *p == 'E'))
              got_dot = got_e = 1;
            /* This test does not include !hex, because a '.' always indicates
               a decimal floating point number regardless of the radix.  */
            else if (!got_dot && *p == '.')
              got_dot = 1;
            else if (got_e && (p[-1] == 'e' || p[-1] == 'E')
                     && (*p == '-' || *p == '+'))
              /* This is the sign of the exponent, not the end of the
                 number.  */
              continue;
            /* We will take any letters or digits.  parse_number will
               complain if past the radix, or if L or U are not final.  */
            else if ((*p < '0' || *p > '9')
                     && ((*p < 'a' || *p > 'z')
                                  && (*p < 'A' || *p > 'Z')))
              break;
          }
        toktype = parse_number (tokstart, p - tokstart, got_dot|got_e, &yylval);
        if (toktype == ERROR)
          {
            char *err_copy = (char *) alloca (p - tokstart + 1);

            memcpy (err_copy, tokstart, p - tokstart);
            err_copy[p - tokstart] = 0;
            error ("Invalid number \"%s\".", err_copy);
          }
        lexptr = p;
        return toktype;
      }

    case '+':
    case '-':
    case '*':
    case '/':
    case '%':
    case '|':
    case '&':
    case '^':
    case '~':
    case '!':
    case '@':
    case '<':
    case '>':
    case '?':
    case ':':
    case '=':
    case '{':
    case '}':
    symbol:
      lexptr++;
      return c;

    case 'L':
    case 'u':
    case 'U':
      if (tokstart[1] != '"' && tokstart[1] != '\'')
        break;
      /* Fall through.  */
    case '\'':
    case '"':
      {
        int host_len;
        int result = parse_string_or_char (tokstart, &lexptr, &yylval.tsval,
                                           &host_len);
        if (result == CHAR)
          {
            if (host_len == 0)
              error ("Empty character constant.");
            else if (host_len > 2 && c == '\'')
              {
                ++tokstart;
                namelen = lexptr - tokstart - 1;
                goto tryname;
              }
            else if (host_len > 1)
              error ("Invalid character constant.");
          }
        return result;
      }
    }

  if (!(c == '_' || c == '$'
        || (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z')))
    /* We must have come across a bad character (e.g. ';').  */
    error ("Invalid character '%c' in expression.", c);

  /* It's a name.  See how long it is.  */
  namelen = 0;
  for (c = tokstart[namelen];
       (c == '_' || c == '$' || (c >= '0' && c <= '9')
        || (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || c == '<');)
    {
      /* Template parameter lists are part of the name.
         FIXME: This mishandles `print $a<4&&$a>3'.  */

      if (c == '<')
        { 
               /* Scan ahead to get rest of the template specification.  Note
                  that we look ahead only when the '<' adjoins non-whitespace
                  characters; for comparison expressions, e.g. "a < b > c",
                  there must be spaces before the '<', etc. */
               
               char * p = find_template_name_end (tokstart + namelen);
               if (p)
                 namelen = p - tokstart;
               break;
        }
      c = tokstart[++namelen];
    }

  /* The token "if" terminates the expression and is NOT removed from
     the input stream.  It doesn't count if it appears in the
     expansion of a macro.  */
  if (namelen == 2
      && tokstart[0] == 'i'
      && tokstart[1] == 'f'
      && ! scanning_macro_expansion ())
    {
      return 0;
    }

  lexptr += namelen;

  tryname:

  yylval.sval.ptr = tokstart;
  yylval.sval.length = namelen;

  /* Catch specific keywords.  */
  copy = copy_name (yylval.sval);
  for (i = 0; i < sizeof ident_tokens / sizeof ident_tokens[0]; i++)
    if (strcmp (copy, ident_tokens[i].operator) == 0)
      {
        if (ident_tokens[i].cxx_only
            && parse_language->la_language != language_cplus)
          break;

        /* It is ok to always set this, even though we don't always
           strictly need to.  */
        yylval.opcode = ident_tokens[i].opcode;
        return ident_tokens[i].token;
      }

  if (*tokstart == '$')
    {
      write_dollar_variable (yylval.sval);
      return VARIABLE;
    }
  
  /* Use token-type BLOCKNAME for symbols that happen to be defined as
     functions or symtabs.  If this is not so, then ...
     Use token-type TYPENAME for symbols that happen to be defined
     currently as names of types; NAME for other symbols.
     The caller is not constrained to care about the distinction.  */
  {
    struct symbol *sym;
    int is_a_field_of_this = 0;
    int hextype;

    sym = lookup_symbol (copy, expression_context_block,
                         VAR_DOMAIN,
                         parse_language->la_language == language_cplus
                         ? &is_a_field_of_this : (int *) NULL);
    /* Call lookup_symtab, not lookup_partial_symtab, in case there are
       no psymtabs (coff, xcoff, or some future change to blow away the
       psymtabs once once symbols are read).  */
    if (sym && SYMBOL_CLASS (sym) == LOC_BLOCK)
      {
        yylval.ssym.sym = sym;
        yylval.ssym.is_a_field_of_this = is_a_field_of_this;
        return BLOCKNAME;
      }
    else if (!sym)
      {                         /* See if it's a file name. */
        struct symtab *symtab;

        symtab = lookup_symtab (copy);

        if (symtab)
          {
            yylval.bval = BLOCKVECTOR_BLOCK (BLOCKVECTOR (symtab), STATIC_BLOCK);
            return FILENAME;
          }
      }

    if (sym && SYMBOL_CLASS (sym) == LOC_TYPEDEF)
        {
          /* NOTE: carlton/2003-09-25: There used to be code here to
             handle nested types.  It didn't work very well.  See the
             comment before qualified_type for more info.  */
          yylval.tsym.type = SYMBOL_TYPE (sym);
          return TYPENAME;
        }
    yylval.tsym.type
      = language_lookup_primitive_type_by_name (parse_language,
                                                parse_gdbarch, copy);
    if (yylval.tsym.type != NULL)
      return TYPENAME;

    /* Input names that aren't symbols but ARE valid hex numbers,
       when the input radix permits them, can be names or numbers
       depending on the parse.  Note we support radixes > 16 here.  */
    if (!sym 
        && ((tokstart[0] >= 'a' && tokstart[0] < 'a' + input_radix - 10)
            || (tokstart[0] >= 'A' && tokstart[0] < 'A' + input_radix - 10)))
      {
        YYSTYPE newlval;        /* Its value is ignored.  */
        hextype = parse_number (tokstart, namelen, 0, &newlval);
        if (hextype == INT)
          {
            yylval.ssym.sym = sym;
            yylval.ssym.is_a_field_of_this = is_a_field_of_this;
            return NAME_OR_INT;
          }
      }

    /* Any other kind of symbol */
    yylval.ssym.sym = sym;
    yylval.ssym.is_a_field_of_this = is_a_field_of_this;
    if (in_parse_field && *lexptr == '\0')
      saw_name_at_eof = 1;
    return NAME;
  }
}

int
c_parse (void)
{
  int result;
  struct cleanup *back_to = make_cleanup (free_current_contents,
                                          &expression_macro_scope);

  /* Set up the scope for macro expansion.  */
  expression_macro_scope = NULL;

  if (expression_context_block)
    expression_macro_scope
      = sal_macro_scope (find_pc_line (expression_context_pc, 0));
  else
    expression_macro_scope = default_macro_scope ();
  if (! expression_macro_scope)
    expression_macro_scope = user_macro_scope ();

  /* Initialize macro expansion code.  */
  obstack_init (&expansion_obstack);
  gdb_assert (! macro_original_text);
  make_cleanup (scan_macro_cleanup, 0);

  /* Initialize some state used by the lexer.  */
  last_was_structop = 0;
  saw_name_at_eof = 0;

  result = yyparse ();
  do_cleanups (back_to);
  return result;
}


void
yyerror (char *msg)
{
  if (prev_lexptr)
    lexptr = prev_lexptr;

  error ("A %s in expression, near `%s'.", (msg ? msg : "error"), lexptr);
}