LV wrote: Perhaps the community could contribute tips, references, etc. comparing and contrasting Python and Tcl to provide someone who programs in Python assistance in learning to read/write Tcl?
VK My vision of comparing is to start with a following road (feel free to change it and expand on each item in turn, shorten list or adding more items):
Python has all the Tcl data types, and has had the equivalent of dicts for some time. 'Everything is a hash table' is perhaps what you could say about how Python's object system works.
Python has OO, Tcl does not. This means that all Python extensions can utilize and build on one OO system rather than having to deal with the fractured landscape that Tcl has.
Python is used for all kinds of things - possibly a little bit less for quick scripts, as it's certainly slower to write some things in Python than Tcl. Tcl's socket abstraction is, IMO, the best in the business for example.
Aside from the very high quality ActiveState tools, I do not believe that any of the Tcl tools are maintained much. Python didn't have much until recently, but I believe there are a number of nascent systems that are fairly high quality.
Tcl's C API is more extensive, and IMO, nicer than Python's. It lets you access more of the underlying system.
Tcl's extremely flexible syntax lets you add new control structures. You can't do that in Python. Since Tcl is merely a series of function calls, one can use Tcl's proc to replace or extend functionality, or to add new functionality.
Probably about the same. Tcl runs on some things like Cisco, although it had to be heavily modified to do that. Python runs on some things like Nokia cell phones: [L1 ]
Tcl, when it gets things right (sockets, event loop, regexps), has a higher level API that really hits a sweet spot. Python has much more functionality available to it, is very popular and is growing in popularity. Tcl's implementation is nicer in some ways. Things like i18n and threads tend to be 'done right', and are less intrusive than in Python.
Sarnold I have tried writing a small tutorial, while reading the beginning of the Python tutorial. I have abandoned it, because it was not the subject of this page.
Sarnold All right. In my personal experience, I always used Python for small tasks, so I am not the person who would comment it for large tasks.
I just noted there was overall more than 300 modules in the standard distribution, part of them being platform-specific.
About OO : Python has by no mean the simplicity of snit, nor the mixins, filters of XOTcl. The multi-thread stuff seems not to be as well handled in Python than in Tcl.
On the other hand, Python users can create new types with UserDict, UserList and so on.
I made some quick'n'dirty perf comparisons between ActiveTcl8.5a3 and Python2.4.1. The results show that Tcl is not so slow. Setting a variable, looping or sorting a list is done in quite the same time.
LV Okay - compare what comes in Python with ActiveTcl - what important functionality is missing? What could/should be added to ActiveTcl to bring them nearer to the same level of out of the box functionality?
SS I don't think we should compare against ActiveTcl because Python is distributed with all this modules inside the .tar.gz file. So it's not the case of a batteries included distribution. All the libraries are *part* of Python.
LV I understand. For things to be added to Tcl, a TIP needs to be written, argued, approved, and implemented. On the other hand, to add something to ActiveTcl, one need only convince the maintainer of ActiveTcl and find an implementation that uses TEA.
So it seems to me that changes to ActiveTcl might be more likely to occur in the short term.
And it still seems fair to me to compare the two - because ActiveTcl is a single file release of Tcl, which includes the tcl interpreter and extensions. And what one downloads from python.org is a single file download of Python, which includes the Python interpreter, and, if the person building it so desires, a series of extensions. However, the Python can be built without extensions.
For that matter, if someone wants to, feel free to compare the functionality of Python, with no extras configured, with Tcl out of the box.
The issue I'm trying to address is this - if someone who has to write some app considers Tcl vs Python to determine a language, how are things going to compare? Most importantly to me, What functionality is missing in Tcl?
davidw ActiveTcl is great as far as it goes (I've been very grateful for it when forced to use Windows several times), however, the vast majority of Tcl installations out there are not ActiveTcl, and people do take that into account when creating packages on top of Tcl.
RHS It's fair to say "Well, the base Python dist comes with all these packages. You have to go get the batteries included dist of Tcl to get the same". However, it's also fair to say "Well, the core dist of Tcl is lightweight, and you can't get a lightweight dist of Python" (or, would that be you have to go get the lightweight dist of Python? I don't know the answer). The idea is that it's a design philosophy, and the two languages made different choices. Just because one person holds that one of the choices is better does not mean that someone else might not feel the other way.
davidw Seeing as how Python is being distributed for cell phones of all things, presumably where there is a desire to cut it down, it's possible. Meanwhile in the non cell phone market, most people seem pretty happy to have a very capable tool rather than having to fetch a bunch of separate packages. When the less knowledgeable go to compare Tcl and Python, they may very well be comparing what they find on their Linux box, which is a cut down tclsh with no OO vs Python and all its packages.
SS Also maybe it's worth to note that Python's distribution is organized in a way that extensions are stored into a separate directory, and they don't share code with the Python's language core. It's like to add a directory 'extensions' in the Tcl tar.gz with populare C extensions, and let the Makefile to compile-install even those extensions, and not just the core language. So this does not affect in any way the ability to get a little Tcl install. It's also possible to disable from configure the compilation of some extension if desidered.
Sarnold IMHO it is highly desirable that the Tcl core has a small memory footprint ; perhaps should we add mmap, atexit and some compression formats that Python has.
Keivn Walzer Having just released a Python application that makes use of Tkinter, after releasing three or four Tcl/Tk programs, I can say that Python is a heavier language: probably more robust out of the box because of its standard library, but also more complex to work with (threads are almost essential for GUI programming; fortunately Python handles threading gracefully), and more complex to deploy in terms of standalone applications. Python's deployment tools (py2app on the Mac, and presumably py2exe on Windows) produce much larger applications, in part because Python and Tcl/Tk have to be bundled (if you are developing a GUI using Tk). Starkits and starpacks are simpler and smaller. On the other hand, there are some things that simply can't be done in Tcl that Python could do with either its core language or extension: for instance, an SFTP client can be done in Python, but not Tcl. So it's a matter of the right tool for the job.