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                    @i @Program.1.symbols@ = @Program.0.symbols@;
  39                 @}
  40
  41                 |
  42                 @{ @i @Program.fields@ = new_tab(); @}
  43
  44                 ;
  45
  46 Funcdef:          FUNC ID '(' Pars ')' Stats END
  47                 @{ @i @Stats.symbols@ = tab_merge(@Funcdef.symbols@, @Pars.pars@, 0); @}
  48
  49                 ;
  50
  51 Structdef:        STRUCT Ids END
  52                 @{ @i @Structdef.fields@ = @Ids.fields@; @}
  53
  54                 ;
  55
  56 Ids:              ID Ids
  57                 @{ @i @Ids.0.fields@ = tab_add_symbol(@Ids.1.fields@, @ID.name@, S_FIELD, 1); @}
  58
  59                 |
  60                 @{ @i @Ids.fields@ = new_tab(); @}
  61
  62                 ;
  63
  64 Pars:             Pars ',' ID
  65                 @{ @i @Pars.0.pars@ = tab_add_symbol(@Pars.1.pars@, @ID.name@, S_VAR, 0); @}
  66
  67                 | ID
  68                 @{ @i @Pars.pars@ = tab_add_symbol(new_tab(), @ID.name@, S_VAR, 0); @}
  69
  70                 |
  71                 @{ @i @Pars.pars@ = new_tab(); @}
  72
  73                 ;
  74
  75 Stats:            Stat ';' Stats
  76                 @{
  77                    @i @Stat.in_symbols@ = @Stats.0.symbols@;
  78                    @i @Stats.1.symbols@ = @Stat.out_symbols@;
  79                 @}
  80
  81                 |
  82                 ;
  83
  84 Stat:             VAR ID ASSIGN Expr
  85                 @{
  86                    @i @Stat.out_symbols@ = tab_add_symbol(clone_tab(@Stat.in_symbols@), @ID.name@, S_VAR, 0);
  87                    @i @Expr.symbols@ = @Stat.in_symbols@;
  88                 @}
  89
  90                 | Lexpr ASSIGN Expr
  91                 @{
  92                    @i @Stat.out_symbols@ = @Stat.in_symbols@;
  93                    @i @Lexpr.symbols@ = @Stat.in_symbols@;
  94                    @i @Expr.symbols@ = @Stat.in_symbols@;
  95                 @}
  96
  97                 | IF Bool THEN Stats END
  98                 @{
  99                    @i @Bool.symbols@ = @Stat.in_symbols@;
 100                    @i @Stats.symbols@ = @Stat.in_symbols@;
 101                    @i @Stat.out_symbols@ = @Stat.in_symbols@;
 102                 @}
 103
 104                 | IF Bool THEN Stats ELSE Stats END
 105                 @{
 106                    @i @Bool.symbols@ = @Stat.in_symbols@;
 107                    @i @Stats.0.symbols@ = @Stat.in_symbols@;
 108                    @i @Stats.1.symbols@ = @Stat.in_symbols@;
 109                    @i @Stat.out_symbols@ = @Stat.in_symbols@;
 110                 @}
 111
 112                 | WHILE Bool DO Stats END
 113                 @{
 114                    @i @Bool.symbols@ = @Stat.in_symbols@;
 115                    @i @Stats.symbols@ = @Stat.in_symbols@;
 116                    @i @Stat.out_symbols@ = @Stat.in_symbols@;
 117                 @}
 118
 119                 | Call
 120                 @{
 121                    @i @Call.symbols@ = @Stat.in_symbols@;
 122                    @i @Stat.out_symbols@ = @Stat.in_symbols@;
 123                 @}
 124
 125                 | RETURN Expr
 126                 @{
 127                    @i @Expr.symbols@ = @Stat.in_symbols@;
 128                    @i @Stat.out_symbols@ = @Stat.in_symbols@;
 129                 @}
 130
 131                 ;
 132
 133 Lexpr:            ID
 134                 @{ @c check_variable(@Lexpr.symbols@, @ID.name@); @}
 135
 136                 | Field
 137                 ;
 138
 139 Expr:             '-' Term
 140                 | Term
 141                 | Term Plusterm
 142                 | Term Malterm
 143                 ;
 144
 145 Plusterm:         '+' Term Plusterm
 146                 | '+' Term
 147                 ;
 148
 149 Malterm:          '*' Term Malterm
 150                 | '*' Term
 151                 ;
 152
 153 Term:             '(' Expr ')'
 154                 | ID
 155                 @{ @c check_variable(@Term.symbols@, @ID.name@); @}
 156
 157                 | NUM
 158                 | Call
 159                 | Field
 160                 ;
 161
 162 Bool:             Bterm
 163                 | Bterm Orterm
 164                 | NOT Bterm
 165                 ;
 166
 167 Orterm:           OR Bterm Orterm
 168                 | OR Bterm
 169                 ;
 170
 171 Bterm:            Term GREATER Term
 172                 | Term '=' Term
 173                 | '(' Bool ')'
 174                 ;
 175
 176 Field:            Term '.' ID
 177                 @{ @c check_field(@Field.symbols@, @ID.name@); @}
 178
 179                 ;
 180
 181 Call:             ID '(' Exprs ')'
 182                 | ID '(' ')'
 183                 ;
 184
 185 Exprs:            Expr
 186                 | Exprs ',' Expr
 187                 ;
 188
 189 %%
 190
 191 extern int yylex();
 192 extern int yylineno;
 193
 194 int yyerror(char *error_text) {
 195         fprintf(stderr,"Line %i: %s\n",yylineno, error_text);
 196         exit(2);
 197 }
 198
 199 int main(int argc, char **argv) {
 200         yyparse();
 201         return 0;
 202 }
 203