Concatinating Numbers-Error: Bug or Feature

strat has asked for the wisdom of the Perl Monks concerning the following question:

Hello,

I just fell over an error with concatinating strings with numbers. Here is a short testscript:

H:\>perl
print "hello ".55." test\n";
String found where operator expected at - line 1, near "55." test\n""
        (Missing operator before " test\n"?)
^Z
syntax error at - line 1, near "55." test\n""
Execution of - aborted due to compilation errors.

H:\>
[download]

If I write one or more spaces between 55 and the following dot, it is all ok. But this way, the dot after the 55 seems to be evaluated like a dot in a number like 55.23

Is this a bug or a feature?

Tested with the Perl-Versions:

Activestate-Perl 5.61 Built 633 / Win2k Pro
Perl 5.005_03 / Solaris

Best regards,
perl -e "s>>*F>e=>y)\*martinF)stronat)=>print,print v8.8.8.32.11.32"

Comment on Concatinating Numbers-Error: Bug or Feature Download Code

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Re: Concatinating Numbers-Error: Bug or Feature by BrowserUk (Patriarch) on Oct 29, 2002 at 11:06 UTC
"55." is a legal float in Perl, so you need a space between the 55 and the . to disambiguate your intent. Nah! Your thinking of Simon Templar, originally played by Roger Moore and later by Ian Ogilvy	[reply] [d/l]
Re: Concatinating Numbers-Error: Bug or Feature by mce (Curate) on Oct 29, 2002 at 11:23 UTC
Hi, To avoid the concatination operator problem, use , in print and not .. What you wrote, is exactly the same as: `print "hallo".55.0"test"; # <= error` [download] When you write it as: `print "hallo" . 55 . "test";` [download] The perlparser (B::Deparse) will rewrite it as `print 'hallo55test';` [download] Conclusion; `print "hallo",55,"test";` [download] I hope this helps. --------------------------- Dr. Mark Ceulemans Senior Consultant IT Masters, Belgium	[reply] [d/l] [select]
Re: Concatinating Numbers-Error: Bug or Feature by busunsl (Vicar) on Oct 29, 2002 at 11:14 UTC
I think it doesn't make any sense to concatenate a literal number to a string. You can put it inside the string as well and it would be faster. Apart from that it's pretty obvious that you have to put a space between the number and the dot to tell the parser what you want.	[reply]
Re: Concatinating Numbers-Error: Bug or Feature by gjb (Vicar) on Oct 29, 2002 at 19:48 UTC
~~As a matter of fact, it would be safer to use `printf` since you'd end up with an empty string if the number happens to be zero.~~ ~~`print "hello " . 0 . " test\n";` would result in `hello test` which is probably not what you want, hence `printf "hello %d test\n", (0);` would be better since it produces `hello 0 test`.~~ Hope this helps, -gjb-	[reply] [d/l] [select]