MKDIR, CHDIR and RMDIR

[Ivan]

I'm currently working on a program to calculate and draw the most efficient use of expensive fabric. It a kind of simple database where I need to access directories and work with directories.

Is it in simple ways possible to emulate the following commands like: MKDIR, CHDIR and RMDIR

I took the example from http://www.bbcbasic.co.uk/bbcwin/manual ... ml#dirlist and added some code:

It seems to work as expected.

I can list and decide file types, but I can't find any easy examples like above named commands.

Code: Select all

                                  
      DIM filename$(999)
      count = 0
      PROClistdirectory

      FOR list = 1 TO count
        PRINT filename$(list)
      NEXT list

      END

      DEF PROClistdirectory
      LOCAL dir%, sh%, res%
      DIM dir% LOCAL 317
      SYS "FindFirstFile", "*.BBC", dir% TO sh%
      IF sh% <> -1 THEN
        REPEAT
          count += 1                                                :REM added to original example
          REM PRINT $$(dir%+44)
          filename$(count) = $$(dir%+44)
          SYS "FindNextFile", sh%, dir% TO res%                     :REM added to original example
        UNTIL res% = 0
        SYS "FindClose", sh%
      ENDIF
      ENDPROC

[DDRM]

Hi Ivan,

These functions are available via star commands:
*MKDIR (or *MD)
*CHDIR (or *CD)
*RMDIR (or *RD)

If you use the star commands directly you need to define the target directory explicitly but you can use OSCLI to "wrap" the star commands, together with a variable directory name, for example

OSCLI "CD """+directory$+""""

would change to the directory defined in directory$. Note the use of triple quotes to include a quote in the string!

This is covered in more detail in the manual. Hope that helps.

Best wishes,

D

[Ivan]

Hi DDRM,

ON ERROR PRINT ERR

root$ = "\"
dirname$ = "Testing"

OSCLI "CD """+root$+""""

OSCLI "MKDIR """+dirname$+""""

OSCLI "CD """+dirname$+""""

Works great, but I had to handle errors. The manual use END to stop errors, but stops the program...

Maybe you can shet a little light on error handling.

----------------------------------------------------------------

As I recall back in eighties did UniComal have an errorhandler, that was very nice to use.

TRAP
some error prone code (eg MKDIR existing name)
HANDLER
PRINT "Directory name exist!"
RETRY
ENDTRAP

Is it possible to do similar error handling in BBCBASIC?

Best regards,

Ivan

[RichardRussell]

Is it possible to do similar error handling in BBCBASIC?

Yes, see here.

[Ivan]

Below the output and code by UniComal. The code catch the error and continues by the retry.

I am trying to do the same in BBCBASIC, but I think I don't understand the concept..?

trap-handling.jpg

Code: Select all

      oops = FALSE
      ON ERROR LOCAL IF FALSE THEN
        CASE oops OF
          WHEN FALSE
            PRINT "2/0 ";2/0
          WHEN TRUE
            PRINT "I'm back!"
          OTHERWISE
            PRINT "What?"
        ENDCASE
      ELSE
        CASE ERR OF
          WHEN 18:
            oops = TRUE
            PRINT "I'll be back"
          OTHERWISE RESTORE ERROR : ERROR ERR, REPORT$
        ENDCASE
      ENDIF : RESTORE ERROR

[RichardRussell]

I am trying to do the same in BBCBASIC, but I think I don't understand the concept..?

The Wiki article I linked to describes the BBC BASIC equivalent of the conventional TRY...CATCH style of Structured Exception Handling (e.g. as used in C++), which does not support a RETRY statement, or anything similar as far as I know. I wonder if RETRY is really what you want here, but if it is I would suggest that you simply roll-your-own equivalent using ON ERROR LOCAL rather than going down the SEH route:

Code: Select all

      oops = FALSE
      ON ERROR LOCAL oops = TRUE
      CASE oops OF
        WHEN FALSE
          PRINT "2/0: ";2/0
        WHEN TRUE
          PRINT "I'll be back!"
          PRINT "Error code: ";ERR
          PRINT REPORT$
          PRINT "0/2: ";0/2
          PRINT "I'm back!"
      ENDCASE
      RESTORE ERROR