on goto / on gosub ..

[Charles Pegge]

Very fast classic BASIC construct.

I will put this macro into the OxygenBasic core language

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def on
======
'%1' name of index variale
'%2' goto or gosub or call
'%3' { @label1,@lael2,...}
'$$  reserved name ending
scope
static sys st$$[64]
if not st$$[1]
  st$$[1]={%3}
endif
if %1
  %2 st$$[%1]
endif
end scope
end def

function f(int v,n=0) as int
============================
  '
  on n gosub {@sr1,@sr2,@sr3,@sr4}
  '
  subroutine sr1
  --------------
    print "sr1"
  end subroutine
  '
  subroutine sr2
  --------------
    print "sr2"
  end subroutine
  '
  subroutine sr3
  --------------
    print "sr3"
  end subroutine
  '
  subroutine sr4
  --------------
    print "sr4"
  end subroutine
  '
  return v
end function
'
'TEST:
int i
for i=1 to 4
  f(0,i)
next


[Nicola]

Hi Charles,
Have you completed entering these commands into O2?
I would like to include them in my Help.

Anyway, I agree that they can speed up and simplify a program. A sort of IF ... THEN GOSUB/CALL on one line compared to the possible n lines of IF ... THEN ...

Thanks

[Charles Pegge]

Hi Nicola,

There is an entry in inf/oxyDatabase.txt. It also appears in the manual.

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key:      "on 18"
action:   on x goto / gosub / call { list }
use:      branch to an address using a list of locations
example:
  procedure f(int isr)
    subroutine sr1
      ...
    end subroutine
    subroutine sr2
      ...
    end subroutine
    subroutine sr3
      ...
    end subroutine
    '
    on isr gosub {@sr1,@sr2,@sr3}
    '
  end procedure
remarks:  lists of up to 128 subroutines are supported
related:  Procedures ,subroutine, label, gosub, call, goto
group:    system macro
updated:  02/03/2025
.


It is defined by an internal macro, which might be quite useful for deriving similar constructs:

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def on
  '%1' name of index variable
  '%2' goto or gosub
  '%3' { @label1,@label2,...}
  scope
  static sys _st_[128]
  if not _st_[1]
    _st_[1]={%3}
  endif
  #if not anymatch " goto gosub call   ","%2"
    #error "Expecting: goto / gosub / call "
  #endif
  %2 _st_[%1]
  end scope
end def