syntax of defined

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

Hello every one !!!!

I was doing the following code

if defined param('end_date'){$user_input->{end_date} = param('end_date
+')};
else $user_input->{end_date} = param('start_date');
[download]

And I was getting the compilation error as follows

yntax error at /var/www/cgi-bin/post.cgi line 21, near "if defined"

Execution of /var/www/cgi-bin/post.cgi aborted due to compilation errors.

can anybody give me correct syntax for it ???

Thanks in advance !!!!

Comment on syntax of defined Download Code

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Re: syntax of defined by moritz (Cardinal) on Mar 09, 2010 at 22:21 UTC
In Perl 5 you need parenthesis directly after the 'if', and curlies both after if and else: `if (defined param('end_date')) { ... } else { ... }` [download] see perlintro, perlsyn. (In Perl 6 you can omit the parenthesis)	[reply] [d/l]
Re^2: syntax of defined by ikegami (Patriarch) on Mar 09, 2010 at 23:00 UTC
In Perl 5 you need parenthesis directly after the 'if', Except if you use the `if` statement modifier `bar() if foo();` [download] Mind you, the statement modifier wouldn't be useful here. The condition operator, on the other hand, would be useful. `$user_input->{end_date} = defined(param('end_date')) ? param('end_date') : param('start_date');` [download] Mind you, `param('end_date')` can still be called twice for nothing. The following doesn't: `$user_input->{end_date} = param('end_date'); $user_input->{end_date} = param('start_date') if !defined($user_input->{end_date});` [download] Since 5.10, the above can be simplified to the following: `$user_input->{end_date} = param('end_date') // param('start_date');` [download] The following isn't strictly equivalent, but should do the trick if you want something similar while still supporting earlier versions of Perl: `$user_input->{end_date} = param('end_date') \|\| param('start_date');` [download]	[reply] [d/l] [select]
Re: syntax of defined by MidLifeXis (Monsignor) on Mar 10, 2010 at 15:25 UTC
`if defined param('end_date'){$user_input->{end_date} = param('end_date +')};` [download] In addition to the other comments, the `};`, while not syntactically wrong, is probably not what you mean. Read on... `else $user_input->{end_date} = param('start_date');` [download] This, on the other hand, is quite wrong. With the closing `};` on the `if`, the else no longer has meaning. Also, it should be `else {..._date');}`. It is said that "only perl can parse Perl." I don't even come close until my 3rd cup of coffee. --MidLifeXis	[reply] [d/l] [select]