Re: [bug-gawk] BEGINFILE/ENDFILE bug?

[Andrew J. Schorr]

On Sat, May 17, 2014 at 01:59:35PM -0500, Ed Morton wrote:
> So, despite what the error message says ( `getline' invalid inside
> `ENDFILE'), you CAN use a redirected getline in ENDFILE (and
> BEGINFILE) but only if using it to populate a variable rather than
> $0. END, on the other hand, lets you do either.

This behavior is actually documented:

   The `getline' statement (*note Getline::) is restricted inside both
   `BEGINFILE' and `ENDFILE'.  Only the `getline VARIABLE < FILE' form is
   allowed.

> It's not obvious why ENDFILE would require a variable to populate
> when END doesn't, and I think that error message is misleading. A
> better error message might be something like:

It is not obvious to me either, but I'm guessing that there's a good
reason.  The attached patch seems to enable `getline < file', but I may
well be missing something.

Also, the documentation above doesn't seem quite right.  For example, I think
this already works:

   bash-4.2$ gawk 'BEGINFILE { "cat /etc/passwd" | getline; print}' /dev/null
   root:x:0:0:root:/root:/bin/bash

Perhaps it should say that only redirected forms of getline are allowed.

I don't see why the previous example should work, whereas this doesn't:

   bash-4.2$ gawk 'BEGINFILE { getline < "/etc/passwd"; print}' /dev/null
   gawk: cmd. line:1: error: `getline' invalid inside `BEGINFILE' rule

With the attached patch, these both work as expected.

Regards,
Andy

getline.patch
Description: Text document