ag/parser.y

   1 %{
   2         #include <stdio.h>
   3         #include <stdlib.h>
   4         #include <string.h>
   5         #include "symbol_table.h"
   6 %}
   7
   8 %start          Input
   9 %token          FUNC END STRUCT VAR IF THEN ELSE WHILE DO RETURN OR NOT
  10 %token          ID NUM ASSIGN GREATER
  11
  12 @autoinh symbols
  13
  14 @attributes     { char *name; } ID
  15 @attributes     { struct symbol_t *fields; struct symbol_t *symbols; } Program
  16 @attributes     { struct symbol_t *fields; } Ids Structdef
  17 @attributes     { struct symbol_t *pars; } Pars
  18 @attributes     { struct symbol_t *symbols; } Funcdef Stats Bool Expr Call Lexpr Field Term Plusterm Malterm Bterm Orterm Exprs
  19 @attributes     { struct symbol_t *in_symbols; struct symbol_t *out_symbols; } Stat
  20
  21 @traversal @postorder t
  22
  23 %%
  24
  25 Input:            Program
  26                 @{ @i @Program.symbols@ = @Program.fields@; @}
  27
  28                 ;
  29
  30 Program:          Funcdef ';' Program
  31                 @{
  32                    @i @Program.fields@ = @Program.1.fields@;
  33                 @}
  34
  35                 | Structdef ';' Program
  36                 @{
  37                    @i @Program.fields@ = table_merge(@Structdef.fields@, @Program.1.fields@, 1);
  38                    @i @Program.1.symbols@ = @Program.0.symbols@;
  39                 @}
  40
  41                 |
  42                 @{ @i @Program.fields@ = new_table(); @}
  43
  44                 ;
  45
  46 Funcdef:          FUNC ID '(' Pars ')' Stats END
  47                 @{ @i @Stats.symbols@ = table_merge(@Funcdef.symbols@, @Pars.pars@, 0); @}
  48
  49                 |
  50                   FUNC ID '(' ')' Stats END
  51                 @{ @i @Stats.symbols@ = table_merge(@Funcdef.symbols@, new_table(), 0); @}
  52
  53                 ;
  54
  55 Structdef:        STRUCT Ids END
  56                 @{ @i @Structdef.fields@ = @Ids.fields@; @}
  57
  58                 ;
  59
  60 Ids:              ID Ids
  61                 @{ @i @Ids.fields@ = table_add_symbol(@Ids.1.fields@, @ID.name@, SYMBOL_TYPE_FIELD, 1); @}
  62
  63                 |
  64                 @{ @i @Ids.fields@ = new_table(); @}
  65
  66                 ;
  67
  68 Pars:             Pars ',' ID
  69                 @{ @i @Pars.pars@ = table_add_symbol(@Pars.1.pars@, @ID.name@, SYMBOL_TYPE_VAR, 0); @}
  70
  71                 | ID
  72                 @{ @i @Pars.pars@ = table_add_symbol(new_table(), @ID.name@, SYMBOL_TYPE_VAR, 0); @}
  73
  74                 ;
  75
  76 Stats:            Stat ';' Stats
  77                 @{
  78                    @i @Stat.in_symbols@ = @Stats.symbols@;
  79                    @i @Stats.1.symbols@ = @Stat.out_symbols@;
  80                 @}
  81
  82                 |
  83                 ;
  84
  85 Stat:             VAR ID ASSIGN Expr
  86                 @{
  87                    @i @Stat.out_symbols@ = table_add_symbol(clone_table(@Stat.in_symbols@), @ID.name@, SYMBOL_TYPE_VAR, 0);
  88                    @i @Expr.symbols@ = @Stat.in_symbols@;
  89                 @}
  90
  91                 | Lexpr ASSIGN Expr
  92                 @{
  93                    @i @Stat.out_symbols@ = @Stat.in_symbols@;
  94                    @i @Lexpr.symbols@ = @Stat.in_symbols@;
  95                    @i @Expr.symbols@ = @Stat.in_symbols@;
  96                 @}
  97
  98                 | IF Bool THEN Stats END
  99                 @{
 100                    @i @Bool.symbols@ = @Stat.in_symbols@;
 101                    @i @Stats.symbols@ = @Stat.in_symbols@;
 102                    @i @Stat.out_symbols@ = @Stat.in_symbols@;
 103                 @}
 104
 105                 | IF Bool THEN Stats ELSE Stats END
 106                 @{
 107                    @i @Bool.symbols@ = @Stat.in_symbols@;
 108                    @i @Stats.symbols@ = @Stat.in_symbols@;
 109                    @i @Stats.1.symbols@ = @Stat.in_symbols@;
 110                    @i @Stat.out_symbols@ = @Stat.in_symbols@;
 111                 @}
 112
 113                 | WHILE Bool DO Stats END
 114                 @{
 115                    @i @Bool.symbols@ = @Stat.in_symbols@;
 116                    @i @Stats.symbols@ = @Stat.in_symbols@;
 117                    @i @Stat.out_symbols@ = @Stat.in_symbols@;
 118                 @}
 119
 120                 | Call
 121                 @{
 122                    @i @Call.symbols@ = @Stat.in_symbols@;
 123                    @i @Stat.out_symbols@ = @Stat.in_symbols@;
 124                 @}
 125
 126                 | RETURN Expr
 127                 @{
 128                    @i @Expr.symbols@ = @Stat.in_symbols@;
 129                    @i @Stat.out_symbols@ = @Stat.in_symbols@;
 130                 @}
 131
 132                 ;
 133
 134 Lexpr:            ID
 135                 @{ @t check_variable(@Lexpr.symbols@, @ID.name@); @}
 136
 137                 | Field
 138                 ;
 139
 140 Expr:             '-' Term
 141                 | Term
 142                 | Term Plusterm
 143                 | Term Malterm
 144                 ;
 145
 146 Plusterm:         '+' Term Plusterm
 147                 | '+' Term
 148                 ;
 149
 150 Malterm:          '*' Term Malterm
 151                 | '*' Term
 152                 ;
 153
 154 Term:             '(' Expr ')'
 155                 | ID
 156                 @{ @t check_variable(@Term.symbols@, @ID.name@); @}
 157
 158                 | NUM
 159                 | Call
 160                 | Field
 161                 ;
 162
 163 Bool:             Bterm
 164                 | Bterm Orterm
 165                 | NOT Bterm
 166                 ;
 167
 168 Orterm:           OR Bterm Orterm
 169                 | OR Bterm
 170                 ;
 171
 172 Bterm:            Term GREATER Term
 173                 | Term '=' Term
 174                 | '(' Bool ')'
 175                 ;
 176
 177 Field:            Term '.' ID
 178                 @{ @t check_field(@Field.symbols@, @ID.name@); @}
 179
 180                 ;
 181
 182 Call:             ID '(' Exprs ')'
 183                 | ID '(' ')'
 184                 ;
 185
 186 Exprs:            Expr
 187                 | Exprs ',' Expr
 188                 ;
 189
 190 %%
 191
 192 extern int yylex();
 193 extern int yylineno;
 194
 195 int yyerror(char *error_text) {
 196         fprintf(stderr,"Line %i: %s\n",yylineno, error_text);
 197         exit(2);
 198 }
 199
 200 int main(int argc, char **argv) {
 201         yyparse();
 202         return 0;
 203 }
 204