parse.y

   1 %{
   2 #include <stdio.h>
   3 #include <string.h>
   4 #include <stdlib.h>
   5
   6 #include "ast.h"
   7
   8 #include "y.tab.h"
   9
  10 int yylex(void);
  11
  12 void yyerror(struct ast **result, const char *str)
  13 {
  14         ast_free(*result);
  15         fprintf(stderr, "error: %s\n", str);
  16 }
  17
  18 int yywrap()
  19 {
  20         return 1;
  21 }
  22
  23 %}
  24
  25 %union
  26 {
  27         struct expr *expr;
  28         struct stmt *stmt;
  29         struct list *list;
  30         struct vardecl vardecl;
  31         struct decl *decl;
  32         char *ident;
  33 }
  34
  35 //%define parse.error verbose
  36 %token <ident> IDENT
  37 %token <expr> BOOL CHAR INTEGER
  38 %token ASSIGN BCLOSE BINAND BINOR BOPEN CCLOSE COMMA CONS COPEN DIVIDE DOT ELSE
  39 %token IF INVERSE MINUS MODULO NIL PLUS POWER RETURN SEMICOLON TIMES VAR WHILE
  40
  41 %parse-param { struct ast **result }
  42
  43 %right BINOR
  44 %right BINAND
  45 %nonassoc EQ NEQ LEQ LE GEQ GE
  46 %right CONS
  47 %left PLUS MINUS
  48 %left TIMES DIVIDE MODULO
  49 %right POWER
  50
  51 %type <ast> start
  52 %type <expr> expr
  53 %type <list> args body decls fargs field fnargs nargs
  54 %type <decl> fundecl
  55 %type <vardecl> vardecl
  56 %type <stmt> stmt
  57
  58 %%
  59
  60 start : decls { *result = ast($1); } ;
  61 decls
  62         : { $$ = NULL; }
  63         | decls vardecl SEMICOLON { $$ = list_cons(decl_var($2), $1); }
  64         | decls fundecl { $$ = list_cons($2, $1); }
  65         ;
  66 vardecl
  67         : VAR IDENT ASSIGN expr { $$ = vardecl($2, $4); }
  68         ;
  69 fundecl
  70         : IDENT BOPEN args BCLOSE COPEN body CCLOSE
  71                 { $$ = decl_fun($1, $3, $6); }
  72         ;
  73 args
  74         : { $$ = NULL; }
  75         | nargs
  76         ;
  77 nargs
  78         : nargs COMMA IDENT { $$ = list_cons($3, $1); }
  79         | IDENT { $$ = list_cons($1, NULL); }
  80         ;
  81 fargs
  82         : { $$ = NULL; }
  83         | fnargs
  84         ;
  85 fnargs
  86         : fnargs COMMA expr { $$ = list_cons($3, $1); }
  87         | expr { $$ = list_cons($1, NULL); }
  88         ;
  89 body
  90         : { $$ = NULL; }
  91         | body stmt { $$ = list_cons($2, $1); }
  92         ;
  93 stmt
  94         : IF BOPEN expr BCLOSE COPEN body CCLOSE ELSE COPEN body CCLOSE
  95                 { $$ = stmt_if($3, $6, $10); }
  96         | WHILE BOPEN expr BCLOSE COPEN body CCLOSE
  97                 { $$ = stmt_while($3, $6); }
  98         | expr SEMICOLON { $$ = stmt_expr($1); }
  99         | IDENT ASSIGN expr SEMICOLON { $$ = stmt_assign($1, $3); }
 100         | RETURN expr SEMICOLON { $$ = stmt_return($2); }
 101         | RETURN SEMICOLON { $$ = stmt_return(NULL); }
 102         | vardecl SEMICOLON { $$ = stmt_vardecl($1); }
 103         ;
 104 field
 105         : { $$ = NULL; }
 106         | field DOT IDENT { $$ = list_cons($3, $1); }
 107 expr
 108         : expr BINOR expr { $$ = expr_binop($1, binor, $3); }
 109         | expr BINAND expr { $$ = expr_binop($1, binand, $3); }
 110         | expr EQ expr { $$ = expr_binop($1, eq, $3); }
 111         | expr NEQ expr { $$ = expr_binop($1, neq, $3); }
 112         | expr LEQ expr { $$ = expr_binop($1, leq, $3); }
 113         | expr LE expr { $$ = expr_binop($1, le, $3); }
 114         | expr GEQ expr { $$ = expr_binop($1, geq, $3); }
 115         | expr GE expr { $$ = expr_binop($1, ge, $3); }
 116         | expr CONS expr { $$ = expr_binop($1, cons, $3); }
 117         | expr PLUS expr { $$ = expr_binop($1, plus, $3); }
 118         | expr MINUS expr { $$ = expr_binop($1, minus, $3); }
 119         | expr TIMES expr { $$ = expr_binop($1, times, $3); }
 120         | expr DIVIDE expr { $$ = expr_binop($1, divide, $3); }
 121         | expr MODULO expr { $$ = expr_binop($1, modulo, $3); }
 122         | expr POWER expr { $$ = expr_binop($1, power, $3); }
 123         | MINUS expr { $$ = expr_unop(negate, $2); }
 124         | INVERSE expr %prec TIMES { $$ = expr_unop(inverse, $2); }
 125         | BOPEN expr COMMA expr BCLOSE { $$ = expr_tuple($2, $4); }
 126         | BOPEN expr BCLOSE { $$ = $2; }
 127         | IDENT BOPEN fargs BCLOSE { $$ = expr_funcall($1, $3); }
 128         | INTEGER
 129         | BOOL
 130         | CHAR
 131         | IDENT field { $$ = expr_ident($1, $2); }
 132         | NIL { $$ = expr_nil(); }
 133         ;