Re: Interpreter for old basic programs from the line number era

On 6 Mrz., 18:12, "Auric__" <not.my.r...@[EMAIL PROTECTED]
> wrote:
> On Wed, 05 Mar 2008 08:04:10 GMT,  wrote:
> > If you take a look at the description of bas7 at
>
> >http://seed7.sourceforge.net/scrshots/bas7.htm
>
> > you see that the primarily intend of Bas7 is to analyze spaghetti
> > code. Therefore it writes a log file while interpreting the BASIC
> > program.
>
> Analyze how? What exactly does it do, output a list of line numbers to
> the log? ...

The log file of a very small example program:

  100 PRINT "Hello, world!"
  105 IF I=0THEN 107ELSE 110
  107 IF I=1THEN 110ELSE 110
  110 INPUT "Press return to continue",a$

load_prog finished
100 PRINT "Hello, world!"
I is 0.0
105 IF -1.0 THEN - GOTO 107
I is 0.0
107 IF 0.0 THEN - SKIP LABEL
107 ELSE - GOTO 110
110 INPUT "Press return to continue"
110 INPUT A$ <- ""
END OF PROGRAM REACHED

As you can see: First you get the program listing and
then you get line numbers + statements + some information
like "SKIP LABEL". Every time a variable is accessed you
get a message like "I is 0.0". Here is a part from
another log:

640 IF -1.0 THEN - EXECUTE STATEMENTS IN LINE UNTIL "ELSE"
640 LET S=1.0
640 RETURN FROM "GOSUB 640" AT LINE 302
S is 1.0
303 IF -1.0 THEN - EXECUTE STATEMENTS IN LINE UNTIL "ELSE"
304 EXIT FOR
Y is 1.0
310 EMPTY FOR B=0.0 TO 1.0 STEP -1.0
313 CONTINUE AFTER NEXT
 ***** [314] RETURN - SOME FOR LOOPS WERE NOT LEFT
314 LEAVE THE FOR B LOOP AT LINE 301
314 LEAVE THE FOR A LOOP AT LINE 281
314 RETURN FROM "GOSUB 250" AT LINE 730
740 NEXT Y = 2.0 CONTINUE FOR
X is 1.0
Y is 2.0
A(1,2) is 2.0
730 IF -1.0 THEN - EXECUTE STATEMENTS IN LINE UNTIL "ELSE"
730 GOSUB 250
250 LOCATE 1,78
250 LOCATE ,,0
250 PRINT "$ ";

> ... (I'm not going to d/l it to find out -- I'm on v-e-e-e-e-e-r-y
> slow dial-up and most downloads are painful.)

The good message is: The download is only 987039 Bytes.
The bad message is: You have to compile it. The 987039 Bytes
consist of the Seed7 package seed7_05_20080302.tgz and is here:
http://sourceforge.net/project/showfiles.php?group_id=151126&package_id=167035
After you succeded with the compilation you can start Bas7 with:
../hi bas7 your_basic_program

Greetings Thomas Mertes

Seed7 Homepage:  http://seed7.sourceforge.net
Seed7 - The extensible programming language: User defined statements
and operators, abstract data types, templates without special
syntax, OO with interfaces and multiple dispatch, statically typed,
interpreted or compiled, portable, runs under linux/unix/windows.