[Tutor] evolutionary drift
Steve,
You may be right. It often happens that someone has a (small) idea, perhaps
very focused, and others chime in and try to apply it more widely, perhaps by
making it more general, and it grows. Over the years, the earlier adopters may
be seen almost as co-creators or even become the lead in the story. Tell me who
seems to be associated with Apple and who did much of the technical work? I am
not saying that Jobs did not have vision and marketing talent and an eye for
style and so on. I am not even sure who came up with ideas back then. Another
such person, Bill Gates, did do some programming of BASIC early on and so forth.
So, whatever the history of early Python (and predecessors) was, it may have
begun as some enhancements and improvements of what came before and perhaps new
paradigms. Others who saw it may have seen something that looked easier to
teach. An obvious example, if it was there way back then, was removing lots of
brackets used in other languages (such as {([])} ) and using indentation. Feels
more natural to not-so-mathematical types.
But over the years the brackets have returned and worse. Like many languages,
Python used what symbols it could find on the keyboard and then overloaded them
horribly. Parentheses are used for grouping but also for tuples and to force
invocation of a function and to hold the argument tuple (albeit no trailing
comma is needed for a single argument as in other tuples) and presumably in
other contexts such as within regular expressions. Periods can mean quite a few
things as can asterisk and so on. There are few matched sets of characters on
the keyboard. () is now used for tuples, among other things. [] is used for
lists except when it is used for dictionary access as in cards[key] versus
text[5] and {} is used for dictionaries except when you use [] but also for
sets ...
Heck, they ran out of symbols. {} is an empty dictionary and you say set() for
an empty set. Ditto for tuple.
<> is not currently used as a matched set as it has many other uses like in
comparisons. Some languages even use <> as the same as != or ~= to mean not
equals. "" and '' and even `` are sort of used as if they are a matched set I
some languages (`` is in R, not Python) but are typographically identical as
compared to text processing that creates two versions.
EBCDIC had a few other symbols but many languages now use only ASCII symbols
and have to combine them to make complex and even non-intuitive combinations as
symbols. Try teaching a child in say C++ that:
X++==++Y is valid and even meaningful if read as:
X++ == ++Y
because it asks you to get the current value of X to compare to the NEW value
of Y incremented and return a Boolean result and immediately thereafter,
increment X. Heck, you can write (XY) and so on. I have seen languages with
an = and == and even === alongside := and ::= and -> and --> and <- and <-- and
more all to mean variations on a theme.
If we had started with many more symbols, in some ways it would be harder but
in other ways easier. Mathematicians borrow symbols from lower case, upper case
and script letters from languages like Greek and Latin but also from Hebrew as
in, well not easy to include in a file contain normal text but aleph-null (and
aleph-one and infinitely more levels of infinity.)
A simple teaching language that uses English words children know might either
be verbose in places or long as in making you spell out DELETE instead of del.
But quite a few languages are simple if you leave out most of the
functionality. Yes, you need to explain why some things must end in a semicolon
or be indented a certain way or require parentheses or ...
What you don't want to teach is a complex language like English. I was teaching
my Dad as he prepared for Citizenship and he balked when told there were at
least seven distinct ways you pronounce OUGH in common English words.
So, perhaps python can be used to teach basic programming for several reasons
including no need to declare variables and their "types" in advance and having
relatively intelligent basic types that easily get converted in the background
as in various kinds of numbers. But when you use more and more features, it
expands into areas where, frankly, there is no one right answer and choices are
often made by fiat or by a majority. Mathematically, if you view a topic like
multiple inheritance in classes and the kludges made to get around logical
issues, you see what a mess it really is and very hard to teach. Look at the
double underscore notation(prefix-only) for variables that renames them to be
unique within a certain scope to avoid collisions in the mythical searched name
space.
I am not against such drift but at times wonder if a one-size-has-to-fit-all
mentality is wise.
I had a thought on an earlier topic by Asad. He wanted to write in Python what
is effectively a member of the UNIX grep family. Specifically, fgrep (or
[Tutor] the fivefold path
Mark,
Thanks for the expansion.
Yes, there are ever more ways to format text.
There can be an indefinite expansion beyond this is many ways.
I was thinking of ways to make bits and pieces from objects and stringing them
together, perhaps inventing your own methods.
Anyone can come up with another meta-language, perhaps embed them in a module
with classes, and use overloading methods to make it easier to use.
But worst of all is to simply find an external application and open up a
connection to it such as with Popen() or a call to a URL that accepts some
formatting string and returns something formatted.
Consider something like a UNIX Shell language like sh/csh/ksh or more modern
incarnations like BASH that use a dollar sign in imaginative ways such as $PATH
or `command args` to make substitutions. You can imagine invoking something
like that while passing along parts needed and taking back the result.
Now, arguably, those are not part of the language. But if you want to build a
weird enough scenario, you could have a Rube Goldberg device that bounced
around multiple servers on the internet running many kinds of OS and percolated
some complex result back into a now formatted string.
Diversity is nice but also often a distraction. Worse is when trying to read
what others have written. On that topic, I note many people like to include
short segments in their ENGLISH writing from other languages. Latin and French
are common inserts as they are easy to read albeit not always to comprehend.
Lawyers seem unable to communicate without lots of Latin nonsense and some
musicians must toss in periodic tidbits of Italian and so on. Languages that
use characters totally outside what is in the character sets In English or near
relatives that have added characters with diacritical marks, are less often
seen. How often do you see Greek or Hebrew? OK, I admit I see them often, but
my reading tastes are eclectic. I bet many would at least like a translation
and/or transliteration next to such quotes or just the translation.
Back to programming. Nothing wrong with multiple ways if they offer more
functionality that is useful
But why constantly reinvent the wheel as an ellipse? Look at the issue of
strings. There actually is a reason for the many variation in python. Single
and double quotes are pretty much identical with the exception that they make
it easier to include the other symbol without backslashes. Triple quotes (three
doubles) offer other improvements and so do several raw or Unicode variants.
But strictly speaking, they are often more syntactic sugar for one or a few
underlying storage mechanisms accompanied by access methods. Objects, of a
sort. The f version mentioned as a formatting method is in a sense another such
object with additional methods. You can well imagine more such things you can
design into a language, albeit some may not be able to use existing symbols you
ran out of unless you want to use "'"'" stuff "'"'" (where you may not be able
to read the nested " and ' and " and ' and " to have some exotic meaning like
format the sting repeatedly in a loop till it does not change. For example, if
$PATH evaluated to
something${DATE}something`echo "hello \$world!"`something
and $DATE expanded to $MONTH/$DAY/$YEAR
then repeated formatting till no more expansions happen could be another type
of string. No, not asking for that especially since I can see easy ways to make
infinite loops š
Mark, perhaps jokingly, asks what can you do for your language. Nice sentiment
but I find it less useful to be wedded or loyal to things as it is always more
interesting to see if something new developed is at least as interesting. Many
ideas when carried through to the point of absurdity stop being as useful. I am
thinking of some LISP variants with very nice mathematical/philosophical ideas
including how an amazing number of things can be done recursively. So if you
asked them to write a function in lisp that compares A and B, they don't bother
putting the numbers in two registers like A and B and issuing a compare
directive at machine language level. Instead, they write the LISP equivalent of
this pseudocode:
Greater(A,B)
If A == 0, return FALSE
If B == 0, return TRUE
Otherwise, return Greater(A-1, B-1)
Try comparing A,B = 999,999,999,999, 1,000,000,000,000
How much memory does your computer have? The numbers are ONE apart with A being
smaller. But the algorithm slavishly puts recursive function calls on the stack
about a trillion times then unwinds. You say no problem, tail recursion allows
replacing the function on the stack. Maybe. So all you need is a trillion times
the CPU time or so for something done in a few cycles in most hardware.
(Parenthetically, I am not picking on LISP), as most modern) (computer
languages)) allow (((equivalent)) code. )))
Half the fun when I thought LISP was having people get lost counting
parentheses at a time that ed
Re: [Tutor] Pythonic way
On 20/11/2018 22:35, Steven D'Aprano wrote: > On Tue, Nov 20, 2018 at 08:22:01PM +, Alan Gauld via Tutor wrote: > >> I think that's a very deliberate feature of Python going back >> to its original purpose of being a teaching language that >> can be used beyond the classroom. > > I don't think that is correct -- everything I've read is that Guido > designed Python as a scripting language for use in the "Amoeba" > operating system. I think both are true. Guido was working on Amoeba at the time he built Python so it was an obvious choice of platform, although he first built it on a Mac. But he didn't set out specifically to build a scripting language for Amoeba but rather to build "a descendant of ABC" which was also usable in the real world, specifically The C/Unix world. To do that he believed it had to address the major barriers to ABC which were 1)being capable of being extended and 2) improved I/O. My source for that conclusion is Guido's forward to "Programming Python" 1st edition. https://www.python.org/doc/essays/foreword/ Also his comments when he set up the "Computer Programming for Everybody" initiative, which he led for several years. (Which I can't locate...) So I believe that ease of teaching was definitely part of the original game plan and was definitely a factor in some of the later developments around v2.0 or so. -- Alan G Author of the Learn to Program web site http://www.alan-g.me.uk/ http://www.amazon.com/author/alan_gauld Follow my photo-blog on Flickr at: http://www.flickr.com/photos/alangauldphotos ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] evolutionary drift
On 21/11/2018 03:05, Avi Gross wrote: > <> is not currently used as a matched set as it has many other uses like in > comparisons.> Some languages even use <> as the same as != or ~= to mean not > equals. Indeed, Python used to do the same but it was removed in, I think, v2. > A simple teaching language that uses English words children know Probably the best example of that I have seen is Logo. Although it does use [] and () But otherwise its quite child friendly. But ultimately that makes it less likeable in the "grown up world"... > Python can still be a great teaching language if kept to a subset That is true and it is still one of the very few languages that I'd recommend for teaching. But sadly its underbelly shows through very early for beginners. For example in v1 Python range() returned a list. That was easy to understand. Now range() returns a "range object" - what the heck is that? and why do we need it? Similarly with iterators. Things that could easily be iterated over without thought now require "iterators" and/or evaluate to iterators. And the error messages tell you so - but iterators are a concept wholly alien to most beginners. And are quite hard to explain. Those are just the two things that beginners most frequently mail e about from my tutorial. There are lots of other areas where Python implementation now shines through in ways that trip beginners up. > What is easy to teach to children? I'm not sure we should even focus on children. It's more about teaching anyone(regardless of age) who has no prior experience, and especially little or no formal math background. Someone with good high school math can be taught programming fairly easily. But with no math foundation even basic concepts like expressions and assignment become very difficult. It may even be impossible. I used to think that anyone could learn to program but over the last 30 years of trying I've come to the conclusion that its not true. You need a brain that's wired a certain way otherwise it just doesn't make any kind of sense. Its like math. Some folks just can't understand mathematical concepts, they are illogical and non-sensical to them. They might learn some basic principles by rote but they never really see how or why it is so. Same with programming. Some people just don't get it. Thankfully those are a very small minority! -- Alan G Author of the Learn to Program web site http://www.alan-g.me.uk/ http://www.amazon.com/author/alan_gauld Follow my photo-blog on Flickr at: http://www.flickr.com/photos/alangauldphotos ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
[Tutor] origins bootstrapped.
Alan has been involved with Python for a long time so he has more to offer historically. I don't see some things as either/or. You can start with one major motivation and it morphs from a one-celled creature like an Amoeba to a complex vertebrate like a Python which needs modules added so it can walk around better. OK, horrible analogy but interesting naming. So some say Guido started with learning his ABC and then became educated enough to understand Monty Python and reach for the holy grail. OK, even worse. Time to get serious. I have seen this on many projects, not just programming languages and environments. Something fairly simple is imagined then perhaps prototyped. Someone may notice that what was created may be used in another way if perhaps expanded a bit. Someone then realizes they now have functionality that can be used to create something else, in a form of bootstrapping. After a while they have a collection of tools that can be combined to make something more complex. The biological analogy above can be an example. No, I am not saying that a distant ancestor of a snake like a python was an amoeba. But they do share common ancestors they have both diverged from with the amoeba remaining a single celled organism and the python descending from something that became multi-cellular then differentiated into having different kinds of cells in tissues and organs and became a somewhat integrated whole that is possibly more than the sum of its parts. The ABC analogy is also obvious. Once an alphabet is chosen and provisional meanings given to each letter, it can grow and even adjust to making words and sentences and even seemingly endless streams of consciousness like some of my messages. Python was built on top of other achievements that some people were learning from. There were many steps along the way from building machines programmed one byte at a time in binary (I hated a class that made me do that as one error means start over) to various levels where a compiler and then an interpreter would parse things. We have been discussing using regular expressions. Much of a language like python is having bits and pieces of code written in ASCII or Unicode be parsed using hopefully unambiguous rules into tokens that can be made into decision trees or whatever data structure. That deepens on being able to look for and find some sort of pattern in strings. I am not sure what python and others use, but it may be tools similar to string search or regular expressions that allows them to bootstrap. Back when my group was programming in C, I was sent to Denver for a class in Lex/Yacc to learn how to use C libraries that now look primitive. One was a lexical analyzer and the other sort of a parser somewhat rudely named as Yet Another Compiler-Compiler. But today, what do most people use? Our tools improve, often by being a wrapper to older tools and so on for multiple levels. New functionality is added too. Can I ask a question that I really want an opinion on? As a preface, I see some think python as a formal language is being pushed by industry in directions that may not meld as well for its use in other contexts like for teaching students. How much of that is due to it being a relative open and free product? There are plenty of other applications that you pay for and thus have to be responsive to the buyers to remain in business. Python has many implementations including some freer than others. Yet is has gone through a bit of a bifurcation and many would like to see 2.X retained and others wish everyone should migrate. Is there room for a smaller core language that remains good for teaching purposes and that is small enough to fit in a Rasberry pi, while other versions are of industrial strength? Do we already sort of have some of that? I was thinking of how many languages and environments have been looking at working using parallelism. Most people simply have no need for the complication. When you add the ability to do multiprocessing within an application using something like threads, you spend lots of time making sure you literally lock down shared resources so they are used serially. You need to make sure race conditions do not lock up all your threads at once. Lots of added overhead is only worth it if you gain in the process. Add multiple cores in your CPU, and you may need to handle more complications as they are actually running in parallel, perhaps still sharing a common memory. Allow it to use multiple processors around the world, and you need even more elaborate control structures to synchronize all that. It definitely is worth doing but does everyone need it especially for teaching an intro class? I was thinking about the little project I mentioned the other day. Should some of it be done in parallel using methods available? One part of the problem was to read in N files into N pandas DataFrame objects. I knew that I/O tends to be fairly slow and most programs take a nap while waiting. I
Re: [Tutor] origins bootstrapped.
On 21/11/2018 16:31, Avi Gross wrote: > Alan has been involved with Python for a long time so he has more to offer > historically. I'm not so sure about that, several folks on this list have been around longer than me. And I don't follow the main comp.lang.python list that closely. I'm simply giving my perspective for whatever that may be worth. > OK, horrible analogy but interesting naming. So some say Guido started with > learning his ABC and then became educated enough to understand Monty Python > and reach for the holy grail. Made me laugh out loud! > Back when my group was programming in C, I was sent to Denver for a class in > Lex/Yacc to learn how to use C libraries that now look primitive. One was a > lexical analyzer and the other sort of a parser somewhat rudely named as Yet > Another Compiler-Compiler. Still powerful tools and in active use in several projects. They were great for quickly bootstrapping a small bespoke language. > some think python as a formal language is being pushed by industry in > directions that may not meld as well for its use in other contexts like for > teaching students. How much of that is due to it being a relative open and > free product? I think that's true but not necessarily bad. It just takes the language in as different direction. And as you said, that happens in many projects. They start as one ting and end up someplace entirely different. I remember one project that started out as a network management system for a fairly obscure protocol and wound up as both a customer service system for our Global Corporate clients and as part of the monitoring system for the English Channel Tunnel!. Very different applications of the same root code base. > ...Is there room for a smaller core > language that remains good for teaching purposes and that is small enough to > fit in a Rasberry pi, while other versions are of industrial strength? Do we > already sort of have some of that? We sort of have that. Python v3 certainly works well on the pi. We could certainly have a smaller language for teaching but then we had that in ABC and nobody used it. Students don't like learning stuff that they can't use in the real world. And if you want purity for beginners we already have Logo, Scheme, Squeak/Scratch and a few others. But none of those really work well in the wider world. Which is why I still recommend python, warts and all. > I was thinking of how many languages and environments have been looking at > working using parallelism. Most people simply have no need Absolutely and for beginners a single thread is more than enough to cope with. > I was thinking about the little project I mentioned the other day. Should > some of it be done in parallel using methods available? It sounded a lot like a job for the map-reduce paradigm. Which is parallel where it can be and sequential where it should be... > An obvious speedup might be had by starting up N threads with each opening > one file and doing what I said above into one shared process with N > variables now available. But will it be faster? Trying to calculate (or guess) this kind of thing in advance is near impossible. The best solution is to prototype and measure, making sure to do so on typical data volumes. That having been said if you know (or discover) that you definitely need parallelism then its definitely worth revisiting the design to ensure the data structures and overall workflow are optimised for a parallel approach. > ...I will pause and simply say that I opted not to bother > as the darn program finished in 5 or 10 seconds. Exactly so. AS the famous quote says "Premature optimisation is..." > For heavy industrial uses, like some of the applications in the cloud > dealing with huge problems, it may well be worth it. In many cases it's the only practical solution. Almost all of my industrial programming has involved multi processing and threading. Almost none (I think one )of my personal programming projects has needed it. -- Alan G Author of the Learn to Program web site http://www.alan-g.me.uk/ http://www.amazon.com/author/alan_gauld Follow my photo-blog on Flickr at: http://www.flickr.com/photos/alangauldphotos ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] origins bootstrapped.
On 11/21/18 5:54 PM, Alan Gauld via Tutor wrote: > On 21/11/2018 16:31, Avi Gross wrote: >> An obvious speedup might be had by starting up N threads with each opening >> one file and doing what I said above into one shared process with N >> variables now available. But will it be faster? > > Trying to calculate (or guess) this kind of thing in > advance is near impossible. The best solution is to > prototype and measure, making sure to do so on typical > data volumes. > > That having been said if you know (or discover) that > you definitely need parallelism then its definitely worth > revisiting the design to ensure the data structures > and overall workflow are optimised for a parallel approach. > >> ...I will pause and simply say that I opted not to bother >> as the darn program finished in 5 or 10 seconds. > > Exactly so. > AS the famous quote says "Premature optimisation is..." > >> For heavy industrial uses, like some of the applications in the cloud >> dealing with huge problems, it may well be worth it. > > In many cases it's the only practical solution. > Almost all of my industrial programming has involved multi > processing and threading. Almost none (I think one )of my > personal programming projects has needed it. > People play all kinds of parallelism tricks with Python because Python has a certain Impedimet Which Shall Remain Nameless (except I'm certain someone will mention it). Anyway, it's one thing to try to decompose a massive problem, that's interesting on a certain level (see some of the talks companies like Google have done on scaling their services) but is really hard to replicate at home. But another use for non-linear programming, if you want to call it that, is task that just needs a different programming model. That's where a lot of the async stuff with coroutines and event loops that has been beefed up recently is quite interesting. Even very simple programs can run into cases where it may make sense, usually if there are things you have to wait for and want to be able to do other work while doing so. I actually got around to watching David Beazley's talk from a couple years ago, and it was pretty impressive - something I'd flagged as "watch later" I don't know how long ago, more than a year at least. Wish I'd watched it earlier now! I hate posting those obscure YouTube links where people don't know what they are clicking on, so search for this title if interested: David Beazley - Python Concurrency From the Ground Up (it's from the 2015 PyCon) ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] origins bootstrapped.
> On Nov 21, 2018, at 10:31, Avi Gross wrote: > > Is there room for a smaller core > language that remains good for teaching purposes and that is small enough to > fit in a Rasberry pi, while other versions are of industrial strength? Do we > already sort of have some of that? What comes stock on a Pi is more than sufficient (thereās plenty of room for āstandardā python 2 and python 3). Micropython (https://micropython.org/) fits that category nicely for micro controllers and Adafruitās version of it, CircuitPython has a strong following https://www.adafruit.com/circuitpython These have been great to allow people learn not only python, but how to physically interact with the world outside the computer. ā David Rock da...@graniteweb.com ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] origins bootstrapped.
On Wed, Nov 21, 2018 at 11:31:59AM -0500, Avi Gross wrote: > Alan has been involved with Python for a long time so he has more to offer > historically. I've been involved with Python for a long time too. What exactly are you trying to say? > Can I ask a question that I really want an opinion on? As a preface, I see > some think python as a formal language is being pushed by industry in > directions that may not meld as well for its use in other contexts like for > teaching students. I think there is always going to be tension between the needs of different users. Beginners need simplicity; expert, experienced programmers need power; both have very different ideas of what "readable code" means. I don't think Python is being pushed in any direction by "industry". It is evolving according to the needs of the programmers who use it, some of whom may work for some industry or another. > How much of that is due to it being a relative open and > free product? There are plenty of other applications that you pay for and > thus have to be responsive to the buyers to remain in business. Python has > many implementations including some freer than others. I don't know of any non-free (free as in beer, or free as in speech) implementations of Python. Can you elaborate? > Yet is has gone > through a bit of a bifurcation and many would like to see 2.X retained and > others wish everyone should migrate. Is there room for a smaller core > language that remains good for teaching purposes and that is small enough to > fit in a Rasberry pi, while other versions are of industrial strength? Do we > already sort of have some of that? Standard CPython is light enough to run on fairly low-powered devices, including Raspberry Pi. For an even smaller footprint, you can use Micropython, which will run on embedded devices, although Ī¼Py does make some comprompises that means that it's not a fully compliant Python implementation. There are, or were, other small implementations: - Pippy, Python for Palm (probably unmaintained by now...) - Python for S60, for the Nokia S60 platform (likewise...) - Pythonce, for Windows CE (who still uses WinCE?) - PyMite for embedded devices - Python-iPod - Py4A and QPython (Android) - TinyPy - PyPad for the iPad - Pycorn, Python running on bare hardware with no OS > I was thinking of how many languages and environments have been looking at > working using parallelism. [...] > It definitely is worth doing but does everyone need it especially for > teaching an intro class? Who teaches threading and parallelization in introductory classes? -- Steve ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
