Parser

[Bill Cunningham]

In comp.programmin g I asked for advice for writing a parser. The code
someone showed me wouldn't compile. I don't know what's wrong. I just want
to write the simpliest of parsers.

int parser(FILE *in,FILE *out);

int main(void){
parser(stdin,st dout);
return0;}

Won't compile. My guess is maybe this should be written

parser(&stdin,& stdout);

But that's my opinion.

Bill

[Joona I Palaste]

Re: Parser

Bill Cunningham <nospam@nspam.n et> scribbled the following:[color=blue]
> In comp.programmin g I asked for advice for writing a parser. The code
> someone showed me wouldn't compile. I don't know what's wrong. I just want
> to write the simpliest of parsers.[/color]
[color=blue]
> int parser(FILE *in,FILE *out);[/color]
[color=blue]
> int main(void){
> parser(stdin,st dout);
> return0;}[/color]
[color=blue]
> Won't compile. My guess is maybe this should be written[/color]
[color=blue]
> parser(&stdin,& stdout);[/color]
[color=blue]
> But that's my opinion.[/color]

Your opinion is wrong. stdin and stdout are of type FILE *, not of
type FILE. The reason it won't compile is the same as in your
previous post - the function parser() isn't defined anywhere, just
declared.

--
/-- Joona Palaste (palaste@cc.hel sinki.fi) ------------- Finland --------\
\-- http://www.helsinki.fi/~palaste --------------------- rules! --------/
"Remember: There are only three kinds of people - those who can count and those
who can't."
- Vampyra

[Mike Wahler]

Re: Parser


"Joona I Palaste" <palaste@cc.hel sinki.fi> wrote in message
news:c5e7h7$ln4 $1@oravannahka. helsinki.fi...[color=blue]
> Bill Cunningham <nospam@nspam.n et> scribbled the following:[color=green]
> > In comp.programmin g I asked for advice for writing a parser. The[/color][/color]
code[color=blue][color=green]
> > someone showed me wouldn't compile. I don't know what's wrong. I just[/color][/color]
want[color=blue][color=green]
> > to write the simpliest of parsers.[/color]
>[color=green]
> > int parser(FILE *in,FILE *out);[/color]
>[color=green]
> > int main(void){
> > parser(stdin,st dout);
> > return0;}[/color]
>[color=green]
> > Won't compile. My guess is maybe this should be written[/color]
>[color=green]
> > parser(&stdin,& stdout);[/color]
>[color=green]
> > But that's my opinion.[/color]
>
> Your opinion is wrong. stdin and stdout are of type FILE *, not of
> type FILE. The reason it won't compile is the same as in your
> previous post - the function parser() isn't defined anywhere, just
> declared.[/color]

That won't stop a compile (but the missing #include <stdio.h>
as well as the syntax error in the 'return' statement will.)
The missing definition will prevent successful linking
though.

-Mike

[Martin Ambuhl]

Re: Parser

Bill Cunningham wrote:
[color=blue]
> In comp.programmin g I asked for advice for writing a parser. The code
> someone showed me wouldn't compile. I don't know what's wrong. I just want
> to write the simpliest of parsers.
>
> int parser(FILE *in,FILE *out);
>
> int main(void){
> parser(stdin,st dout);
> return0;}
>
> Won't compile. My guess is maybe this should be written
>
> parser(&stdin,& stdout);
>
> But that's my opinion.[/color]

And it's a bad one. The following should compile without diagnostics:

#include <stdio.h>

int parser(FILE * in, FILE * out);

int main(void)
{
parser(stdin, stdout);
return 0;
}

int parser(FILE * in, FILE * out)
{
(void) in; /* noops here to quiet */
(void) out; /* 'unused parameter' warnings. */
return 0;
}

[Bill Cunningham]

Re: Parser

[color=blue]
> int parser(FILE * in, FILE * out)
> {
> (void) in; /* noops here to quiet */
> (void) out; /* 'unused parameter' warnings. */
> return 0;
> }
>[/color]
What do the voids in parenthesis mean? Are they casts? This NG always
makes me feel dumb.

Bill

[Julien Oster]

Re: Parser

"Bill Cunningham" <nospam@nspam.n et> writes:

Hello Bill,
[color=blue][color=green]
>> int parser(FILE * in, FILE * out)
>> {
>> (void) in; /* noops here to quiet */
>> (void) out; /* 'unused parameter' warnings. */
>> return 0;
>> }[/color][/color]
[color=blue]
> What do the voids in parenthesis mean? Are they casts? This NG always
> makes me feel dumb.[/color]

Yes! It's a cast. A cast to void seems pretty useless, especially in
this case where the casted value isn't even used, but it's actually
quite useful here to remove the warning.

Julien