[open-cobol-list] Daydreaming about another language to emit

[Patrick]

Hi Everyone

I hope this email won't upset anyone. I am just THINKING, keyword... 
"thinking" about what other languages might be better then C for 
intermediate generation. I am not saying that we have to change 
anything, I was just hoping to have a theoretical chat.

We have 4 main dependencies:
ncurses
libtool
GMP
BDB

I would really like to get rid of Berkeley DB due to the licensing 
issues it brings to the project but aside from openLDAP I have not come 
up with anything. I also don't really understand the parts it's used in, 
not understanding, it makes it hard to come up with logical alternatives.

However something I have been researching a little is if there was 
another language that the code generator could emit rather then C, it 
might really simplify libcob.

For instance libcob has a function stack. I don't yet know how it works 
but I am assuming it's passing pointers to functions around. This is 
necessary because C does not support nested functions. However several 
other languages do natively, I consider these to be possible matches:

Free Pascal
Ada
D

These do as well but they have enormous runtimes and/or limitations such 
as speed or nesting levels:
Fortran(1 level only)
Functional languages, such as Erlang and Scala
Dynamic languages such as Lua


C is so important, if we didn't use C itself it would have to be 
something that interfaces well with it. I really love Ada but it's quite 
painful to write bindings for it and there are few bindings available, 
although there is already an ncurses one.

Free Pascal has a lot more bindings and quite an active community. Free 
pascal is good to 18 decimal places( I imagine Ada is similar but I will 
have to double check), at 18 decimal places is there a reason to use GMP 
? Would this eliminate a dependency?

Ada's GNAT is pretty painful to use. gnatmake is a nice command that 
calls other stages and you can compile large pure Ada projects with just 
the one command but as soon as you start mixing languages the pain goes 
up quickly.

It looks like FPC is simple for pure pascal projects but it may also be 
painful with mixed programming, I don't have enough experience under my 
belt yet to say for sure. h2pas is a binding program that helps bring in 
C to Pascal. It appears to work by reading header files and I think it 
may work on just the file's text without the need to compile. Ada has 
gcc --fdump-ada-spec but the auto-generated binding can only be produced 
if the application can be compiled on the computer with GCC. Sometimes 
it might be nice to write bindings for programs just retrieved from the 
repos, along with their header.

Free pascal already has a ncurses binding.

I don't know enough about D. I don't know if it's easy to bind to C or 
if GMP would still be needed. I found a beta ncurses D binding but 
that's it, not so great.

So after all this, you might be asking "why are you even considering this".

In my last post I mentioned that I have to get a project started and I 
have to do it in C++ ? Well I just can't bring myself to do it and I 
have already abandoned this. I really love Cobol so much. I can't even 
get away from it when it would probably be logical to do some things in 
another language.

I love it so much but one thing it is really missing is a way to bring 
in libraries in a native way. We don't have enough libraries for general 
purpose programming. I need ways to visualize data, use sockets and much 
more.

Once a good binding is written for python, ruby, lua etc, the C code is 
programmed into the programming model of the language, it just feels 
natural.

Using CALL is fine but over and over again, it just doesn't feel 
integrated. I am daydreaming about how to make the compiler approachable 
and modifiable. It looks like the only way we could create native 
feeling bindings in Cobol is to build them right into the language with 
optional build flags and right now it's pretty daunting tinkering with 
anything, with so much C.

I have made a lot of progress with C over the past year or so but it's 
the trickiest little language and much more complex that supposedly 
larger ones.

I love Cobol's readability and I hate C's lack of it. Auto generated 
Pascal, Ada or D might be so much easier to read the auto-generated C 
and not having to add missing features to C would simplify libcob. The 
compiler would still be challenging  but I have some ideas of how this 
could be changed too. I will report back, one day, with more daydreaming 
ideas about.

I really wish I could contribute to the project, I still can't really 
yet but I might have been able to by now if C was not in the way-Patrick