Reputation: 809
I am using Ox
, bison
and lex
to write an attribute grammar. In my grammar, I use a symbol table to keep track of identifiers that are in scope.
The symbol table struct is defined in a parser.h
header:
struct st_;
typedef struct st_
{
char** names;
void** vals;
char** types;
int len;
int maxlen;
} ST;
Ox produces the files oxout.tab.h
and oxout.tab.c
which are the outputs of bison
after checking the grammar.
This is the head part of my ox
file:
%{
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include "parser.h"
int yylex(void);
void yyerror(char *);
extern int line_number;
struct test {
ST s;
};
ST add(ST table, char* name, void* val, char* type);
ST addMaybe(ST table, char* name, void* val, char* type);
ST addAll(ST old, ST new);
ST init_st();
bool containsT(ST table, char* name, char* type);
bool contains(ST table, char* name);
void oxerrorf(char* f, char* s);
%}
%start Start
%token INTERFACE END CLASS IMPLEMENTS VAR METHOD INT RETURN IF THEN ELSE
%token WHILE DO NOT AND NEW THIS _NULL EOC SCOL COL BRACL BRACR DOT COMMA
%token ASSIGNMENT PLUS ASTERISK MINUS LT EQ DEC HEX ID NEWLINE
@attributes { ST st; } Program Interface Class MaybeIDs InterfaceContents
@attributes { ST st; } Types Members Stats Negations Term Exprs Expr
@attributes { ST st; } Additions Ands ArithOps MaybeElse
@attributes { char* yystrval; } ID
@attributes { ST st; char* name; } AbstractMethod Type Member Par Stat
@attributes { ST st; ST stUp; } Pars
@traversal @preorder LRpre
@traversal PV
%%
// definitions...
this is transformed to the following oxout.tab.c
:
#include <stdbool.h>
#include <stdlib.h>
#if defined(__sun) && defined(__SVR4)
#include <strings.h>
#else
#include <string.h>
#endif
/* Identify Ox output. */
#define YYYOX 1
#line 1 "littleparser.y"
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include "parser.h"
int yylex(void);
void yyerror(char *);
extern int line_number;
struct test {
ST s;
};
ST add(ST table, char* name, void* val, char* type);
ST addMaybe(ST table, char* name, void* val, char* type);
ST addAll(ST old, ST new);
ST init_st();
bool containsT(ST table, char* name, char* type);
bool contains(ST table, char* name);
void oxerrorf(char* f, char* s);
#line 93 "oxout.y"
struct yyyT1
#line 42 "littleparser.y"
{ ST st; }
#line 98 "oxout.y"
;
struct yyyT2
#line 43 "littleparser.y"
{ ST st; }
#line 104 "oxout.y"
;
struct yyyT3
#line 44 "littleparser.y"
{ ST st; }
#line 110 "oxout.y"
;
struct yyyT4
#line 45 "littleparser.y"
{ char* yystrval; }
#line 116 "oxout.y"
;
struct yyyT5
#line 46 "littleparser.y"
{ ST st; char* name; }
#line 122 "oxout.y"
;
struct yyyT6
#line 47 "littleparser.y"
{ ST st; ST stUp; }
#line 128 "oxout.y"
;
Now when I compile this using
> gcc parser.h oxout.tab.h lex.yy.c oxout.tab.c -o ag
gcc
throws me the most curious error:
littleparser.y:42:4: error: unknown type name ‘ST’
42 | @attributes { ST st; } Program Interface Class MaybeIDs InterfaceContents
| ^~
littleparser.y:43:4: error: unknown type name ‘ST’
43 | @attributes { ST st; } Types Members Stats Negations Term Exprs Expr
| ^~
littleparser.y:44:4: error: unknown type name ‘ST’
44 | @attributes { ST st; } Additions Ands ArithOps MaybeElse
| ^~
littleparser.y:46:4: error: unknown type name ‘ST’
46 | @attributes { ST st; char* name; } AbstractMethod Type Member Par Stat
| ^~
littleparser.y:47:4: error: unknown type name ‘ST’
47 | @attributes { ST st; ST stUp; } Pars
| ^~
littleparser.y:47:11: error: unknown type name ‘ST’
47 | @attributes { ST st; ST stUp; } Pars
| ^~
The interesting this is this:
struct test {
ST s;
};
ST add(ST table, char* name, void* val, char* type);
// and the other declarations
seem to compile fine;
however
struct yyyT1
#line 42 "littleparser.y"
{ ST st; }
#line 98 "oxout.y"
;
throws the unknown type name error.
Why is that?
All these definitions seem to be in scope/defined at the time it is compiled. (Also when I look at the output of the preprocessor the contents of parser.h
are inlined before their first usage.)
I am not extremely savvy with C
so I have probably missed something quite obvious I guess.
Sadly C Typedef - Incomplete Type did not help me finding the error;
I tried to define the struct inside the c
file, move the typedef
somewhere else, keeping it all in the h
file, but nothing seems to work.
Where am I going wrong here?
Upvotes: 1
Views: 200
Reputation: 809
As @Paul Hankin suggested, this wasn't an error coming from the file littleparser.y
.
After removing all #line .*
definitions in all the generated c files and compiling it again, the following output
lex.yy.c:574:4: error: unknown type name ‘ST’
574 | { ST st; }
| ^~
lex.yy.c:580:4: error: unknown type name ‘ST’
580 | { ST st; }
| ^~
lex.yy.c:586:4: error: unknown type name ‘ST’
586 | { ST st; }
| ^~
lex.yy.c:598:4: error: unknown type name ‘ST’
598 | { ST st; char* name; }
| ^~
lex.yy.c:604:4: error: unknown type name ‘ST’
604 | { ST st; ST stUp; }
| ^~
lex.yy.c:604:11: error: unknown type name ‘ST’
604 | { ST st; ST stUp; }
| ^~
suggested that the problem was linked to the lexer.y
instead of the litteparser.y
.
After adding #include "parser.h"
in lexer.y
and recompiling it, everything worked fine.
Upvotes: 1