[fpc-pascal] Advantages of Pascal

[Daniël Mantione]

Op Tue, 20 Feb 2007, schreef Patrick Leslie Polzer:

> Dear FreePascal adepts,
> =

>   when I was younger (about seven years ago), I wrote several programs
> in Borland's Turbo Pascal version 7 (IIRC).
> =

>   I then learned C and haven't looked much at Pascal ever since.
> However, I'm still fond of Pascal's clear syntax, so I would like
> to know more about its advantages.

Please try it. There is no better way to learn about its advantages than =

actual programming. This can better explain it to you than I can do in =

1000 words. For many C programmers, getting into Free Pascal is a very =

enjoyable experience.
 =

>   I would be very grateful if you could answer the following questions,
> loosely based on the "Advantages" section of the FreePascal homepage.
> =

> =

>   1) "No Makefiles"
>      ...and yet you ship a Makefile generator with FPC.  Why?

Since the compiler is able to find the dependencies of files automatically,=
 do =

this is not something you need a Makefile for. However, there are several =

other things, like creating a tar or zip of your program, installing it =

and some more things. A makefile is one way to provide this functionality, =

which we make easy and user friendly by providing a makefile generator.

Still we are going to kick fpcmake, since makefiles are hard to port. As C =

programmer you probably know this, to be able to execute a configure =

script on Windows you need an Unix emulator like Cygwin or Msys.

Building the compiler using fpcmake on Windows requires people to =

several Unix utilities, like cp, mv. In near the future we will move to a =

build tool which doesn't depend on external tools to copy files etc., =

increasing the portability of the compiler.
 =

>   2) "Pascal compilers are Fast with a big F [...]"
>      Why is that?

The main reason for this is the unit system. If a C program uses a =

library, all header files need to be loaded and parsed, for each source =

file again. A Pascal compiler can simply load a unit from disk, so it =

doesn't need to parse headers. Further, once loaded, the unit remains in =

memory, so if the next file is compiled, it is ready to be used again.

Some C-compilers provide pre-compiled headers to provide some of the same =

advantages, but since the content of a header can change with a simple =

define, this is limited; until now this has not been very successfull in =

obtaining similar performance to Pascal compilers.

>   3) "Great integration with assembler"
>      Is being able to use Assembler easily inline really that much
>      better as opposed to having the code in separate object files?

Assembler at the Pascal level frees you from the trouble to access =

parameters. If you would write pure assembler you need to work with =

offsets on the stack that need to match what the compiler uses. This is =

very error prone.

Further, you can access any Pascal symbol directly from your assembler =

routines, which saves you all kinds of cubersome imports in your assembler =

files.

>   4) "Smartlinking"
>      Ah, I think you can have that one in C with some obscure linker
>      flags, too.

Recently it has become possible to do real smartlinking with gcc. FPC has =

done this since the late 90's; while gcc could only remove unused files, =

FPC could remove individual variables and procedures.

Still, it works better. Try to statically link a hello world in C and then =

smartlink a hello word in FPC. Compare the executables.

>   5) Why use Pascal instead of Ada?

Ada is a good language. Pascal is good language too, and
modern Object Pascal might be even more advanced than Ada. For certain is =

that Pascal has better development tools, a much larger treasury chest of =

existing code and libraries and is much better documented due to the =

libraries of book been written on it.

> =

>   6) Can I have run-time range checking of arrays/strings and *still*
>      use functions that accept arrays of any length?

Yes. We call this open arrays.

>   Thank you so much in advance for helping me.

You're welcome :)

Dani=EBl Mantione