Normally no interpreted language needs a debugger.

Only compiled and linked does.

Interesting statement. Would you care to expand on why you think that? -- --- Derek Fountain, on the web here : <a href="http://www.derekfountain.org">Derek Fountain</a>

On Monday 14 March 2005 08:02, Morten Gulbrandsen wrote:

Derek Fountain wrote:

...

...

Normally no interpreted language needs a debugger.

Only compiled and linked does.

Interesting statement. Would you care to expand on why you think that?

Sure,

I had a discussion with other programmers what the difference between a compiled and an interpreted language was.

At that time I were coding in PERL, I read that it existed a version of PERL, which actually could compile and link PERL source code.

The other programmer said that the difference between an interpreter and a debugger lies solely in the language.

He had the honest opinion that an interpreted Language like PERL was impossible to compile. An it could never exist any interpreter for C.

End_Of_Statement.

This I did investigate and I actually managed to find an interpreter for C sourcecode. And a compiler for Perl.

which means, -> PERL can be compiled can be linked loaded can be executed

all under control of the programmer with the options and environment he wants.

I also took a closer look at the interpreted C language, which was a subset of K&R C.

It was nearly like Maple,

I then investigated what exactly a debugger was.

best example: visual studio,

I got the conclusion that a debugger was a very complex environment, that simulated the whole compile, link, load and execute process.

I also got the feeling, that any interpreter did the same.

I also took a look at what was required to make a good c compiler,

and found that making a debugger was a lot more that making a compiler.

Maybe I am wrong, but a debugger is a simulator.

Someone could make a PERL compiler,

When I use PERL, Python or PHP as interpreted languages,

all kinds of assertions stops whenever it is required,

gives the same information as any debugger. and In my eyes replaces a debugger.

The levels of warnings usually set in a compiler before initial compilation takes place.

is set at the beginning of a PERL script.

I have some old PERL books and could recall what thay wrote about building a PERL compiler, linker and loader,

IIRC, If I remember correctly.

It was simply a discussion between another programmer and me that triggered the definition of an interpreter and a compiler.

That showed me, a language like c could be interpreted,

A language like PERL, could be compiled.

The environment that parses, compiles and does what a debugger like visual studio did, is nearly the same as any PERL. PHP and Python interpreter does.

==> hence Debugger == Interpreter for me.

This is only my initial idea.

I'm only trying to help, I can be wrong,

I'm not Knuth, nor Dijkstra.

Please correct me, here is my proposition

Compiler + debugger => Interpreter.

Interpreter => simulation of compilation and debugging at the same time. under control by the programmer.

I can be very wrong.

But I also believe this is true for any language.

if you like, I can fetch my PERL books and find out what Larry Wall has to tell, If I remember correctly.

fell free to tell me your opinion.

I have to append, at that time PERL was not object oriented.

best regards

Morten Gulbrandsen

"If we all think exactly the same, then it must be someone who is not thinking at all"

Okay Morten... Your thoughts are logical, but your assumptions are incorrect. In my book, a "Debugger" is a program/environment that allows you to execute a program step by step, and inspect the state of the program between each step. This can be done for Scripts as well as Compiled code. Download activestate komodo Trial and look at it as an example. Additionally, your discussions on "Compilers" is rather misleading. The definition of "what a compiler is", is blurry enough now-a-days that the discussion is not really worth carrying on, and leads to Flame wars about "compiled vs interpreted", "binary vs P-Code", and other such fine distinctions. Jerry

Derek Fountain wrote:

On Monday 14 March 2005 15:02, Morten Gulbrandsen wrote:

You seem confused about a lot of things. Here are a few facts to consider:

'C' can indeed be interpreted. I used a 'C' interpreter once and it was a quite horrible experience. It was marketed as an education tool, but to totally transform the nature of a language like that made it so far from reality it was worthless in my opinion.

So, in short, a debugger is useful in virtually all languages, regardless of how they actually get executed. Perl has one built in. Most other languages have one suppiled as an extra.

Thank you for the information, I knew it would be possible to make "C" an interpreted language. Could we say that a debugger is a visual interpreter ? executing in debug mode is nearly the same as running an interpreter? I still think so. To be honest. When I code in C/C++ I also find =>Rational Purify Plus, or => solaris DTrace for detecting memory leaks very good. certain kinds of crashes are impossible to find without Purify Plus, In visual studio I used the debugger extensively. In fact my problem here lies in the assumption: Some of the 'best' programmers I have ever met. Claimed something like: => only stupid beginners needs a debugger. => Good programmers uses printf(); End_Of_Statement I hope we can agree that is is foolish to say things like that, in fact we all need a debugger. with different warning levels. But certain kinds of errors can occure in C, Can memory leak occure in PERL? here again I think => NO, due to some garbage collection mechanism. certain languages can never experience memory leaks. Ideally a debugger gives output of also the expressions, the identifiers, and should enable some backsteps. To reconstruct the software situation just before the critical code. here under this URL http://www.activestate.com/Products/Download/Download.plex?id=ASPNPerl&contact=2369770-DB&a=e I found the software you use, To be honest I simply love PERL, It was the first programming language I simply mastered. In later years, I have been working with php. python, delphi and C++. Here I run solaris 9 x86, which perl /usr/bin/perl bash-2.05$ perl -v This is perl, v5.6.1 built for i86pc-solaris-64int (with 48 registered patches, see perl -V for more detail) Copyright 1987-2001, Larry Wall the trial does only run for solaris sparc. I can give it a go under Linux. Sun has perl as part of all solaris distributions. So it would be nice with a perl debugger for solaris x86. One last question, some years ago PERL was not object oriented. what is the situation now. can PERL offer the same object oriented software construction as Java, or C++ ? best regards Morten Gulbrandsen