Perl and C are my two languages of choice at the moment. (I intend to add Haskell at some point, in my Copious Free Time.) So naturally, sometimes I find myself writing C that looks like this: 

for($i = 0; $i < $n; $i++) {
  &foobar($arr[$i]);
}

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No big surprise there. But today at work, hacking together another DBI script, I wrote: 
#! /usr/bin/perl -w

use struct;

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Naturally, struct wasn't what I meant to type. But my instinctive reaction to the error message was rather unusual, and (in retrospect) quite amusing: 
#! /usr/bin/perl -w

typedef struct;

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Whoops. Anyways, I figured I'd give you fine folks a chance to have a chuckle at my expense. Anyone else have similar stories that they wouldn't mind sharing?

Blessed be

Update: Gah. Well, it was Samhain in localtime when I posted.

--
:wq

Replies are listed 'Best First'.
Re: Perl and C don't always mix well
by japhy (Canon) on Nov 01, 2001 at 08:15 UTC
    For those of you who can't get enough of Perl... 
    #define elsif else if
#define unless(x) if (!(x))
#define $
#define @
#define %

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    _____________________________________________________
    Jeff[japhy]Pinyan: Perl, regex, and perl hacker.
    s++=END;++y(;-P)}y js++=;shajsj<++y(p-q)}?print:??;

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      Ick.

      But not as far from reality as you may imagine. For those of you who've never seen the code to the original Bourne shell, S. R. Bourne had a bunch of macros defined like this: 

      #define BEGIN {
#define END }
#define IF if(
#define THEN ){
#define ELSE }else{
#define FI }
#define LOOP for(;;){
#define POOL }

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      And so on. The code looked like a funky variant of Algol-68, or C written on heavy psychotropic drugs.

      I once had to debug the code when we were porting it. The only way I could cope was to run it through the C-preprocessor and awk the result. (Why not run it through Perl, you ask? It didn't exist yet....)

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(jeffa) Re: Perl and C don't always mix well
by jeffa (Bishop) on Nov 01, 2001 at 08:10 UTC
    Going back to Java one day, i found myself trying to check for the equality of a string like so: 
    if (foo eq "bar") . . .

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    Then i realized, "Hang on! Java doesn't have eq, it only has ==" . . . So: 
    if (foo == "bar") . . .

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    And wondered for a long amount time (much longer than i care to admit) why it was always, always, always false . . .

    jeffa

    Answer:

    Because i was comparing address spaces. The proper way to compare strings in Java is with the equals() method from the String class.

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      Random tip that works well across several languages.

      Turn that test around. If you write it: 

      if (5 == $number) {
  # ...
}

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      then you are automatically told your mistake when you write 
      if (5 = $number) {
  # ...
}

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      by accident. By contrast you are rather less happy if you write in the naive order and wound up with: 
      if ($number = 5) {
  # ...
}

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      which winds up being true rather more often than you would like...
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Re: Perl and C don't always mix well
by kwoff (Friar) on Nov 01, 2001 at 08:04 UTC
    Yep, I put in the '$' especially, use 'my' for declaring, and put '#' for comments. It's just a habit with my fingers. 
    int main () {
#        my $foo;
        
}

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    But that's only when I haven't programmed in C for a while.
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Re: Perl and C don't always mix well
by Zaxo (Archbishop) on Nov 01, 2001 at 09:54 UTC 
    # define an array of signal handlers
# include a human reaadable description
# if SYMBOL is not not defined ...

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    After Compline,
    Zaxo

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Re: Perl and C don't always mix well
by Sweeper (Pilgrim) on Nov 02, 2001 at 11:33 UTC
    It reminds me that, a few months ago, I wanted to write an "Hello world" program in C. It took me three compiles before executing it. The successive attempts were: 
    #include <stdlib.h>
#include <stdio.h>
void main ()
{
  printf "Hello world\n"
}

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    Oops, forgot that you need a semi-colon, even if followed by a closing brace. 
    #include <stdlib.h>
#include <stdio.h>
void main ()
{
  printf "Hello world\n";
}

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    What's wrong now? (time passes...) Ah yes, you need parentheses. 
    #include <stdlib.h>
#include <stdio.h>
void main ()
{
  printf("Hello world\n");
}

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    Yeah, it works!
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