ag/parser.y

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