Python Vs. Perl
Perl folk seem not to like Python, at least not at first glance. It's easy to understand why: the languages serve similar purposes, but have annoyingly different syntax and structure. There have been converts, though, and Eric S. Raymond's experiences are probably not atypical.
I've noticed that Linux Journal has had more than a few Python articles, and the most recent issue has begun a tutorial series. That article prompted me to take a more serious look.
First Impressions
I went to http://www.python.org/doc/current/index.html and used the excellent tutorial there. I found things to like and things to dislike immediately:
Liked
That object methods are the default, not something tacked on:
a=['abc','def','ghijkl']
print "Before Append",a
a.append('hello')
print "After Append",a
...
Before Append ['abc', 'def', 'ghijkl']
After Append ['abc', 'def', 'ghijkl', 'hello']
There's a whole boatload of built-in methods: see http://www.python.org/doc/current/tut/node7.html. I'm not going to say I like these better than the Perl functions that do similar things, but I certainly have no problems with these and can see good use for them.
That integer math is the default unless one or more of the operands isn't an integer:
print 7 / 2
print 7.0 / 2
...
3
3.5
That semicolons at the end of lines are optional: any of these are fine:
print 7/2;print 7/2.0
print 7/2;
print 7/2.0
print 7/2
print 7/2.0
Leaving off semicolons is a common Perl goof..
Indentation syntax. Everything indented is part of what happens when "mytest" is not 0 or null:
mytest=1
if mytest:
print "mytest ",
print "is set"
print "hello ",
Oddly, this is something most Perl types really hate, but I'd find it easy to get used to. Since most of us tend to indent code within blocks anyway, it seems reasonable to me to dispense with the braces and just use the indentation.
Default argument values for functions:
def foo(prompt="huh?", count=2):
print prompt,count
foo()
foo("go","seven")
foo(count=89)
...
huh? 2
go seven
huh? 89
I really like that.
Exception handling. I like "try/except" logic (apparently Perl 6 has this too);
Disliked
Variables. I don't like the C-ish variable names. I LIKE that Perl requires a $, @ or whatever ahead of a variable name - it makes it stand out. I also like that Perl's $a is different than @a etc.
Data types. Setting a one value tuple is absolutely ugly:
this='abc','def',0;
print this, len(this)
this='hello' # NOT a tuple
print this, len(this)
this='hello', # Now it is
print this, len(this)
...
('abc', 'def', 0) 3
hello 5
('hello',) 1
This is a consequence of not having data prefixes or formal declarations.
No "a++" or "a--". Sheesh.
No "$_". There's _, which apparently isn't quite the same - unless I misunderstand, which is certainly possible at this point.
Overall, I think I'll stick with Perl. I can see Eric Raymond's argument for larger projects, but I don't do large projects anymore and I just find Perl's wild versatility and lack of insistence (More Than One Way To Do It) more attractive than more structured languages. But Python certain does have its appealing aspects, so I'll probably dabble with it here and there.
I certainly cannot agree with some who insist that Python is easier to read or understand than Perl. That's just ridiculous: neither of them add anything to helping understand someone else's code. Perl isn't any more "cryptic" than Python. Nor can I understand the attitude that Perl is deficient because you can do things in multiple ways. If you insist on such structure, enforce it upon yourself: nobody is stopping you. I do understand that for larger projects, with multiple people involved, structure is more necessary.
All in all, I wouldn't be terribly upset if I got "stuck" with something that had to be done in Python. It's a very reasonable scripting tool and does have some very nice features.
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A.P. Lawrence provides SCO Unix and Linux consulting services http://www.pcunix.com
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