Perl to Python conversion
in [Python]
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From: Martin =?utf-8?B?U2Now7bDtm4=?= on 9 Dec 2009 15:33 First off: I am new here and this is my first post after lurking for quite some time. Second off: I don't know much Python---yet. Problem: I have come across a small open source application that I find quite useful. It does have one major flaw though. Its output is in imperial units. Converting isn't a big deal for occasional use but if I start to use this stuff on a regular basis... So I down-loaded the source code and found this thing is written in Perl. Should I learn enough Perl to add the conversion? Probably but this may be a nice excuse to get my Python education going and if I do I might as well re-do the user interface. If I do re-write this thing in Python I might need to learn both Perl and Python... Hence, are there any Perl to Python converters? So far I have only found bridgekeeper which really is (was?) consultancy. Apart from that I only find people recommending a manual re-write. Any thoughts/recommendations? TIA, /Martin
From: zeph on 9 Dec 2009 16:05 Python and Perl often have different design idioms - learning to write *well* in a language involves understanding those idioms, and being able to translate between languages involves understanding the source language well enough to understand the intent of the program's code (even if its poorly written), and understanding the target language well enough to translate the intent into a design fitting the language. Perl and Python have enough syntactic similarities that you could, if you wanted, just translate the program verbatim. Overall, I would recommend adding your imperial->metric functionality to the Perl code for now, and on your free time work on translating to Python, so you don't feel rushed to get it finished. You will probably come to understand the Perl code better after having worked with it and been involved in a hands-on way with it. Likewise, you will become even more familiar with it and with Python as you learn how to translate the application.
From: Intchanter / Daniel Fackrell on 9 Dec 2009 16:10 On Dec 9, 1:33 pm, martin.sch...(a)gmail.com (Martin Schöön) wrote: > First off: I am new here and this is my first post after > lurking for quite some time. > > Second off: I don't know much Python---yet. > > Problem: I have come across a small open source application > that I find quite useful. It does have one major flaw though. > Its output is in imperial units. Converting isn't a big deal > for occasional use but if I start to use this stuff on a > regular basis... > > So I down-loaded the source code and found this thing is written > in Perl. > > Should I learn enough Perl to add the conversion? Probably > but this may be a nice excuse to get my Python education > going and if I do I might as well re-do the user interface. > > If I do re-write this thing in Python I might need to learn both > Perl and Python... > > Hence, are there any Perl to Python converters? So far I > have only found bridgekeeper which really is (was?) consultancy. > Apart from that I only find people recommending a manual re-write. > > Any thoughts/recommendations? > > TIA, > > /Martin Martin, A full answer will depend a lot on several different factors, including the length of the Perl code, what style it was written in (there seem to be uncountably many possibilities), your experience with languages in general, and with that style in particular. In general, though, if your primary purpose is to learn Python and ending up with a useful tool is secondary, I'd recommend rewriting the tool from scratch, possibly keeping the Perl source handy. If the existing tool is command-line based, you might also be able to write a short script through which you can pipe the output of the original program to handle the conversion. Intchanter Daniel Fackrell
From: Peter Chant on 9 Dec 2009 17:46 Martin Sch��n wrote: > Hence, are there any Perl to Python converters? So far I > have only found bridgekeeper which really is (was?) consultancy. > Apart from that I only find people recommending a manual re-write. > > Any thoughts/recommendations? Voice of almost no experience. I once ran a fortran programme through a fortran to c converter and when I saw the result I ran away screaming - it did not look very human friendly. -- http://www.petezilla.co.uk
From: J Kenneth King on 10 Dec 2009 14:04
martin.schoon(a)gmail.com (Martin Schöön) writes: > First off: I am new here and this is my first post after > lurking for quite some time. Hi. > Second off: I don't know much Python---yet. It's not a very big language. If you have experience programming in other languages, you can probably pick it up in a day or two. > Problem: I have come across a small open source application > that I find quite useful. It does have one major flaw though. > Its output is in imperial units. Converting isn't a big deal > for occasional use but if I start to use this stuff on a > regular basis... > > So I down-loaded the source code and found this thing is written > in Perl. > > Should I learn enough Perl to add the conversion? Probably > but this may be a nice excuse to get my Python education > going and if I do I might as well re-do the user interface. Well you can always call it from Python via subprocess (which basically wraps a shell and has fancy ways putting data in and extracting data out). > If I do re-write this thing in Python I might need to learn both > Perl and Python... You'll need to know one of them rather well and enough of the other to get by. It's probably easier to know more Perl than Python since Perl is a lot more expressive than Python (in the TMTOWTDI sense). Frankly I learned Perl before Python and find it rather easy to go between the two. YMMV. > Hence, are there any Perl to Python converters? So far I > have only found bridgekeeper which really is (was?) consultancy. > Apart from that I only find people recommending a manual re-write. It depends where the two languages vary from one another. If the script your translating uses basic types or even simple classes and typical control structures and operations then translating from one to the other is a simple matter of copy-pasting the code and translating the syntax and small bits of grammar. However, in areas where there are high variations; you'll probably want to stay away from it. Perl has a lot of freedom to manipulate references and the programmer can modify the language to suit their needs. So just be careful of code that uses these features as they are difficult to translate into Python. > Any thoughts/recommendations? Depends: - If you needed it done yesterday to get some work done, wrap the Perl script in a subprocess and buy yourself some time to think it over. - If your purpose is to learn Python, then start from scratch. Use the Perl as a guide if there are any maths or algorithms you are unsure about. - If you're just hacking around to learn stuff, learn a little of both. It will make you smarter if it doesn't confuse the heck out of you and make you quit before you finish. ;) > > TIA, > > /Martin HTH |