[ale] On Programming and Programming Langauges

[greg.freemyer at gmail.com (Greg Freemyer)]

Mike,

I'm curious about the phrase "type system"?  Is that relatively new?

==
In the 80s and 90s I worked with C almost daily and had CS majors as
co-workers, but I don't recall the phrase "type system".  I assume it
is a fairly new phrase as opposed to me having been clueless at the
time.  (I looked it up on wikipedia, so no need to explain it.)

fyi: I don't program much any more.  Off into other realms for now.

Greg

On Fri, Sep 17, 2010 at 11:07 AM, Michael B. Trausch <mike at trausch.us> wrote:
> Given the C# thread and the volumes of comments that I have there---both
> addressed and not, because of space---I thought I'd go ahead and just
> send an email out with all my thoughts. ?Whether or not this turns into
> a thread that anyone has any interest in. ?I do not expect that most
> will care to read this, it's _quite_ long. ?Oh, well. ?Take the rambling
> for what it is (or is not) worth. ?:-)
>
> There are, of course, _many_ languages out there. ?And there are a lot
> of people out there looking to hire for projects in language X which
> have insane requirements like "five years experience in X", which is,
> frankly, _stupid_. ?It shows that management and HR types really know
> next to nothing when it comes to the world of programming, and a lot of
> programmers buy into that knowledge of nothing. ?Moving on, though...
>
> If you are a _programmer_ (regardless of what other hats you might wear,
> such as system administrator) then you hold a lot of programming
> knowledge that is independent of the implementation language. ?For
> example, you know algorithms, and you know where to look them up for the
> ones that you've never used, and you're familiar with the costs and
> benefits of them. ?You know how to craft a hand-written parser for
> simple to moderately complex data types. ?You know that you have
> metaprogramming tools available to you. ?You know that a compiler isn't
> some special magical black box, but yet another tool in the process of
> translation, which is something that all programs ultimately wind up
> doing (translating data from one form to another). ?You are also fluent
> in multiple _programming environments_. ?And you are able to "program
> into" them. ?More on this in a minute.
>
> It's easy to be fluent in a language. ?Seriously. ?It's more difficult
> to be fluent with the entire standard library for a language, though,
> whether that is a class library or a function library or a hybrid of
> both.
>
> Insofar as "programming into" an environment, it means that you do
> creative things with the resources that you have. ?For example, I often
> see a lot of people say that "C isn't object-oriented". ?Bull$#!t! ?It
> _absolutely_ is. ?In fact, even assembler can be object oriented, if you
> want it to be. ?"Object-oriented"-ness isn't a feature of a programming
> language that is depended upon to write programs in an object-oriented
> manner. ?Languages that support object-orientation natively have
> provided a convenient notation for supporting that programming model,
> and a type system that is accessible behind it, but nothing more than
> that, really. ?I mentioned GObject before, and I'll mention it again:
> GObject is an object-oriented type system for C. ?It is easy to write C
> programs that use it, and it even supports refcount assisted memory
> management along the lines of what you expect to see from other
> languages. ?It's more difficult to write classes in GObject, but there
> are tools available which take the tedium out of that (for example, GOB
> and Vala, both of which take code as input and output C-GObject code).
>
> GNOME is written in C. ?And GNOME is heavily object-oriented. ?And the
> GObject type system is really an awesome, amazing work. ?It does it all
> without the binary mangling problems of C++, without the managed runtime
> aspects of Python, the JVM, the CLR, or whatever, and it works well,
> given enough time and effort put into to being fluent with that
> particular programming environment. ?And it is portable across POSIX
> systems and even Windows to a certain degree (because of the way Windows
> manages things like network file descriptors there can be a few caveats
> that the programmer needs to be aware of, but it's not that awful a
> situation, really).
>
> Now, there is the issue of whether or not it is useful to learn C these
> days. ?It absolutely is! ?C is not a dead language, by any stretch of
> the imagination. ?Why do I think that? ?Because there are a lot of
> things about being fluent in C that provide insight to programming
> problems in other languages. ?If you can sort through the issues of
> programming language vs. type system vs. standard library in your head
> (they really are all separate things!) then you can gain the insight
> that C has to offer from a programming perspective. ?There was once a
> time when it was necessary to program in C for everything. ?Do I think
> that we should return to that? ?Hell, no. ?There are one-off things that
> I use HLLs like Python for, and I wouldn't want to write those sorts of
> things in C. ?But the things that I do write in C are things that are
> not one-off programs; that is, things that I deploy in multiple
> environments. ?And writing cross-platform C code, as I've mentioned
> before, isn't as difficult as a lot of people seem to think it is.
>
> I learned a lot of programming languages before I learned C. ?BASIC (in
> the forms of BASICA, GW-BASIC, QuickBASIC, and Visual Basic), 6502
> assembler, some x86 assembler---the BASIC family and PHP were the ones
> that I used the most. ?And honestly, I think that was detrimental to my
> way of thinking. ?You see, while BASIC is a general-purpose language
> ("Beginner's All-purpose Symbolic Instruction Code", wow, I still
> remember that?), it does not expose a lot of the system's underlying
> functionality in the way that C does. ?It cannot, in fact, because BASIC
> requires certain built-in statements (PRINT, INPUT, and so forth) that
> are part of the core language itself. ?This coupling of the language to
> things that ought to be explicit function calls in the language's
> runtime makes it difficult to use for "all purposes".
>
> After I learned the many variants of BASIC and then PHP, I spent a fair
> amount of time avoiding C. ?People told me that it was pointless to
> learn, that it was arcane, that it was a dead/dying language, that it
> was a waste of time. ?And so I avoided it. ?At some point, I had a
> problem, and I don't even remember what that problem was now, but it was
> a problem with a program that was written in C. ?And I went looking
> through it, and because C is so bloody different from BASIC and PHP I
> was utterly confused. ?Now, I'd been programming in PHP for quite some
> time at this point, and I was fully used to the ideas of weak type
> systems. ?At first, I saw C's relatively strict data typing as a
> hindrance to productivity. ?How wrong was I! ?It's something that I wish
> PHP would implement, it would reduce bugs caused by implicit coercion
> that I see in every PHP project I am paid to work on.
>
> Sorry, I digress a lot.
>
> In any event, I had to learn C, and I was able to fix my problem. ?And
> then I put it off, and I didn't write anything in it because I had no
> need to. ?But as time went on, I kept coming back to learn C. ?And the
> standard library, and so forth. ?I learned these so that I could
> (mostly) fix problems with things I had, or at least that was my
> intention at the time. ?But I found that the more that I learned C and
> the standard library and all of that, the more I could appreciate its
> simplicity and structure. ?I realized that I had been thinking about
> programming all wrong! ?So I started learning more about it the whole
> process. ?I decided that if I'm going to continue to call myself a
> programmer, I needed to really understand what the hell was going on.
>
> So I started learning about compilers, and interpreters, in a
> lower-level-than-most sort of manner. ?What happens when GCC is run over
> C code? ?All of us know that if you have valid C input, you get object
> code as output, and you can link that into an executable. ?How do those
> executables play nicely together? ?What about for other languages, is it
> the same? ?Turns out that C++ has non-standardized linkage while C has
> standardized linkage and a lot of other programming environments take
> advantage of that (too bad that PHP does not, though that is probably
> because the bulk of PHP code out there would choke and die if it did).
>
> Jumping topics again, I said in the other thread somewhere that if you
> learn C, your abilities as a programmer greatly improve. ?Allow me to
> correct and clarify on this point somewhat. ?There is some indescribable
> quality of knowledge that can be obtained from working at a low level.
> You get a chance to see all the things that are going on, a chance to
> understand what is _really_ happening. ?When I allocate some memory in
> C, it's pretty straightforward compared to the creation of a new
> variable in Python, at least in terms of what's really happening under
> the scenes. ?And if you have a problem with the Python VM, you have a
> hell of a problem debugging it because you probably (as a Python
> programmer) do not care to understand all the internals of the Python
> VM, you just want to get things done. ?So now you're holding a ball that
> you will need to handle---either you find someone to give the ball to,
> and depend on them to fix it, or you start learning enough about the
> Python VM to be able to troubleshoot what's going on and fix it. ?After
> all, all software has bugs.
>
> The lower-level your understanding is, though, the more that you can
> infer. ?And if you know C, you can understand other C-family languages
> more easily. ?I mentioned before that of this family there is C++, C#,
> and Java. ?Omitting the standard libraries of each, my statement is
> factually correct. ?The languages themselves have very similar rules in
> terms of syntax and type-strength. ?You have nuances that are of course
> different, or they wouldn't be different languages. ?But they are all
> part of the same family. ?PHP, OTOH, while it looks like it is a
> C-family language at a glance, cannot be described as such. ?Some of the
> syntax is similar, but it is _very_ different in terms of how you would
> write code for it, and the very simple fact that you can just $create a
> variable anywhere and it's valid even if it $creates a new $Variable
> changes the fundamental understanding that one has to have in order to
> properly scrutinize and read a program.
>
> To that end, I think that everyone should at least be familiar with what
> assembly language is, and how it works. ?I don't think that everyone
> could or should program in it, because once you get "lower" than C, you
> have the problem that you are now tying yourself to a particular CPU
> family, and potentially even just typing yourself to a single CPU model.
> While that used to be something that was useful at one point in time, it
> has no payoff anymore. ?You can get all the performance that you need
> from a good C compiler, and if you need to squeeze more than that, you
> can pay someone who will write hand-optimized assembler, and you'll pay
> out the nose through it (which I suppose will tell you just how much you
> probably don't need to do it, since another CPU is less expensive).
>
> But writing code in C is _not_ as expensive as people make it out to be.
> There is a *heavy* investment in learning. ?*HEAVY*. ?And you need to
> sit yourself down and you need to find a routine that works for you in
> terms of writing code. ?There are multiple books on programming best
> practices out there that talk about how to do things like ensure that
> you're always keeping up on your memory allocations and whatnot. ?And
> for the most part, it is as simple as adopting a convention and
> following it. ?And if your convention is well-thought-out, you can
> probably even write a small program that will automatically enforce it
> for you. ?You can use your version control system to run sanity checks
> on your code, telling you when you step out of your convention.
>
> The real expense with C and C++ code (and in fact, with nearly any other
> language that I can think of) comes not in the writing of it by a
> programmer, but in the maintenance of it by a programmer when the code
> was originally written by someone who isn't a programmer, but writes
> programs. ?There's a distinction, I think. ?I know many people that can
> write programs, but I would not call them a programmer. ?You say
> "algorithm" to them and they say "what's that?" ?You say "type system"
> to them and they again say, "what's that?" ?And many of these are people
> that can put "5 years of programming in X" on their r?sum?!
>
> I'm not saying that "real" programmers are immune to bugs and failures
> and mistakes, but as with any field, mistakes are far less likely to
> happen if you are aware of what causes them and head them off before
> they can form. ?If you have a brand new car and you don't want to get
> ketchup in the seats, don't eat in the car. ?If you are a C programmer
> and you don't want to leak memory, remember to have a matching free (or
> g_free, or struct_or_object_free) call to match every malloc (or
> g_malloc, or struct_or_object_new) call. ?You do this the same way that
> you match your braces, and you're good to go (for the most part). ?And
> if you write library code that will be reused, and you make it easy to
> do both, chances are that it'll get done and you won't forget.
>
> In any case, I've touched on every point I wanted to touch on, for now,
> I think. ?If this turns into a discussion (which I'd like very much to
> see, but it might be too long to keep anyone's interest) then cool.
>
> ? ? ? ?--- Mike
>
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