Re: A C-like brain in a Perl-like world

I agree that hashes are the best approach for merging keyed data. If there is some other reason to continue to use arrays, you can compare different approaches for an array lookup routine.

You will find these lines quite helpful when you put them at the top of your program:

use strict;
use warnings;
use diagnostics;
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The diagnostics provide paragraph-long explanations of many common perl coding errors. For the type of mistakes that I make, the diagnostics are correct about 80% of the time. I think this is an amazingly good percentage.

As premchai21 said, you may need to update your version of perl to get this capability.

It should work perfectly the first time! - toma

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Re: Re: A C-like brain in a Perl-like world by cyberscribe (Acolyte) on Sep 28, 2001 at 10:59 UTC
Please explain "strict" to me. Perl seems anything but strict. Except when it comes to if statements, which MUST involve curly braces: `if(<cond>){%eval_true%}else{%eval_false%}` [download] unlike shell script or other, looser constructs that know the next line off an if is `%eval_true%`. I must believe there is a good reason for this that eludes me, as I must believe that Perl is about simplicity and elegance. Yet removing curly braces and getting away with it seems like a good, intuitive thing to do to a compiler/interpreter. Pontificate? p.s. I would like to propose a new tag for posts and cb ... 'pseudocode' - for formatting code that is really shorthand and differentiating it from stuff between legitimate 'code' tags, which should execute in a Perl environment without errors, or with only errors specifically described in the post. What I wrote above was 'pseudocode.	[reply] [d/l] [select]
Re: Re: Re: A C-like brain in a Perl-like world by blakem (Monsignor) on Sep 28, 2001 at 11:49 UTC
In perl you can use `if` as a statement modifier... Therefore, this is perfectly valid code: `#!/usr/bin/perl -wT use strict; for my $var (0..9) { print "$var is even\n" if $var%2 == 0; # using if as a statement mo +difier }` [download] For more on use strict, please see strict.pm. -Blake	[reply] [d/l] [select]
Re^3: A C-like brain in a Perl-like world by Aristotle (Chancellor) on Sep 28, 2001 at 14:05 UTC
Forcing a BLOCK rather than an instruction after an `if` is because of a simple reason: the "dangling else". It is not apparent in which way `if $condition if $more_condition do_something() else do_other()` is to be disambiguated; many tradiditional languages arbitrarily choose to bind the `else` branch to the closest `if`, but that's not readily apparent from looking at the code - and if you want to bind the else of the first `if`, you still have to use a BLOCK around the second. So Perl forces you to use BLOCKs for clarity, but lets you append an `if` clause as a statement modifier for when you want brevity: `do_something if $condition;`. <CODE> has more functions than formatting. For pseudocode, you can use the regular <tt></tt> HTML tags.	[reply]