sprintf doesnt work in s///e syntax.

Hi,

perl -le '
### this part works
$var=sprintf "%d", 0x11;
print $var; ### and we get 17 output

$_ = "{0x11}";

#s/(0x\d+)/hex($1)/e; #### this part works ok and we see
a {17} output

s/(0x\d+)/sprintf("%d",$1)/e; #### this part does NOT work and we
see a {0} output

print;
'


Is this some bug in the sprintf or s///e flag?

Thanks,
Rakesh

Re: sprintf doesnt work in s///e syntax.

raksha34@gmail.com wrote:
> Hi,
>
> perl -le '
> ### this part works
> $var=sprintf "%d", 0x11;
> print $var; ### and we get 17 output
>
> $_ = "{0x11}";
>
> #s/(0x\d+)/hex($1)/e; #### this part works ok and we see
> a {17} output
>
> s/(0x\d+)/sprintf("%d",$1)/e; #### this part does NOT work and we
> see a {0} output

Try
s/0x(\d+)/sprintf("%d",oct($1))/e;

There is a difference between an unquoted mention of 0x11 and a
scalar containing a string of 0x11.

> print;
> '
>
> Is this some bug in the sprintf or s///e flag?

It's expected behaviour.

-Chris

Re: sprintf doesnt work in s///e syntax.

On Dec 27, 3:09 pm, Christian Winter wrote:
> raksh...@gmail.com wrote:
> > Hi,
>
> > perl -le '
> > ### this part works
> > $var=sprintf "%d", 0x11;
> > print $var; ### and we get 17 output
>
> > $_ = "{0x11}";
>
> > #s/(0x\d+)/hex($1)/e; #### this part works ok and we see
> > a {17} output
>
> > s/(0x\d+)/sprintf("%d",$1)/e; #### this part does NOT work and we
> > see a {0} output
>
> Try
> s/0x(\d+)/sprintf("%d",oct($1))/e;
>
> There is a difference between an unquoted mention of 0x11 and a
> scalar containing a string of 0x11.
>
> > print;
> > '
>
> > Is this some bug in the sprintf or s///e flag?
>
> It's expected behaviour.
>
> -Chris



Thanks for the explanation Chris.

This quoted/unquoted interpretation is unique to hexadecimal/octal
numbers looks like.
Because, we dont see any problems if the variable is anything else.
But why should it
be like that?

I think you meant hex($1) instead of oct($1) in the s///e statement.
> s/0x(\d+)/sprintf("%d",oct($1))/e;

Regards,
--Rakesh

Re: sprintf doesnt work in s///e syntax.

raksha34@gmail.com wrote:
> On Dec 27, 3:09 pm, Christian Winter wrote:
> This quoted/unquoted interpretation is unique to hexadecimal/octal
> numbers looks like.
> Because, we dont see any problems if the variable is anything else.
> But why should it be like that?

Well, Perl tries to be as clever as can be without running
too much danger of misinterpreting a string for a number where
it isn't meant to be. The rule of thumb I use to avoid errors
is to convert numbers to base10 as early as possible in a script.

> I think you meant hex($1) instead of oct($1) in the s///e statement.
>> s/0x(\d+)/sprintf("%d",oct($1))/e;

I did. In fact, I managed (not for the first time) to confuse myself
while trying to decide which one to pick. Both hex("11") and oct("0x11")
do the correct thing (hex("0x11") does also). So either works fine:
s/(0x\d+)/sprintf("%d",oct($1))/e;
s/0x(\d+)/sprintf("%d",hex($1))/e;

-Chris

Re: sprintf doesnt work in s///e syntax.

raksha34@gmail.com schreef:

> perl -le '
> ### this part works
> $var=sprintf "%d", 0x11;
> print $var; ### and we get 17 output
>
> $_ = "{0x11}";
>
> #s/(0x\d+)/hex($1)/e; #### this part works ok and we see
> a {17} output
>
> s/(0x\d+)/sprintf("%d",$1)/e; #### this part does NOT work and we
> see a {0} output
>
> print;
> '

Ask perl for help, by adding -w.

perl -Mstrict -we'
printf "%d\n", "0" . "\x11";
'

> Is this some bug in the sprintf or s///e flag?

No, PEBCAK.

--
Affijn, Ruud

"Gewoon is een tijger."