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Scheme vs Common Lisp style in SKILL++

tweeks

 While you can write your SKILL++ code like it is C, Maclisp, Scheme, or Common Lisp (or none of the above...), I've been experimenting with Common Lisp style lately.

Trying to write Common Lisp style code in SKILL++ can lead to curious situations like this:

(defvar first car)

The intention is to define FIRST as another name for CAR, as in Common Lisp.  In Scheme, we would write

(define first car)

which seems pretty natural, but using DEFVAR to define a function just feels.... wrong... somehow... :)

I guess I should use ALIAS:

 (alias second cadr)

 except ALIAS has weird limitations:

ILS-> (foo = first)
primop:car
ILS-> (foo '(1 2 3))
1
ILS-> (foo = second)
macro:evalalias
ILS-> (foo '(1 2 3))
*Error* evalalias: unknown alias - foo

Parents

  • theopaone said:
    3. Without a break or continue for loops, go is somewhat but seldom useful. My first language was Fortran IV with goto's, on punch cards, almost prehistoric school.

     

    I personally dislike the concept of break/continue from loops (even in C) because it's a glorified goto which makes it hard to read the flow of control. But if one really must do this, I would probably do:

    prog(()
      loop(...
        when(IwantToBreak return())
      )
    )

    You could do something similar if you want to emulate continue, but have the prog() within the loop.

    Or you could use catch and throw:

    catch('break
      for(i 1 20
        catch('continue
          printf("Before %d\n" i)
          when(i<4 throw('continue t))
          printf("After %d\n" i)
          when(i>15 throw('break t))
        )
      )
    )

    Personally I'd prefer that to using go().

    Andrew.

Reply

  • theopaone said:
    3. Without a break or continue for loops, go is somewhat but seldom useful. My first language was Fortran IV with goto's, on punch cards, almost prehistoric school.

     

    I personally dislike the concept of break/continue from loops (even in C) because it's a glorified goto which makes it hard to read the flow of control. But if one really must do this, I would probably do:

    prog(()
      loop(...
        when(IwantToBreak return())
      )
    )

    You could do something similar if you want to emulate continue, but have the prog() within the loop.

    Or you could use catch and throw:

    catch('break
      for(i 1 20
        catch('continue
          printf("Before %d\n" i)
          when(i<4 throw('continue t))
          printf("After %d\n" i)
          when(i>15 throw('break t))
        )
      )
    )

    Personally I'd prefer that to using go().

    Andrew.

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