flashforth-devel

[Flashforth-devel] For-next and do-loop practise

[om1zz <om...@vo...>]

Hi, in order not to invent wheel (and maybe quite useful for other
ffters too) I would ask the practisioners for an advice how to best
translate following constructs into FF's for-next:

a)   B A do ... loop 


b)   B A do I ... loop


c)   D C do 
B A do ... I J ... loop
loop


d)   B A do ... K +loop 


e)   D C do 
B A do ... I J ... K +loop
L +loop

f)   B A ?do ... loop


Thanks,
I.


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Re: [Flashforth-devel] For-next and do-loop practise

[Mikael N. <mik...@pp...>]

Hi,
This is my untested quick take on this.

Of course if you are translating DO LOOP code
mechanically a direct template is good to have.

In general in FF I would not write code that
loops from A to B.

Usually I have a starting value A and a count N
Much code that uses do loops has the same and
must convert it to a A B=A+N pair before using the DO LOOP.

P is just a special variable which is saved on the return stack to
support nesting. J is implemented below without
nesting support. By saving it on the return stack
before FOR, it can also be made nestable.

-- Mike

On 16.6.2011 16:36, om1zz wrote:
> Hi, in order not to invent wheel (and maybe quite useful for other
> ffters too) I would ask the practisioners for an advice how to best
> translate following constructs into FF's for-next:
>
> a)   B A do ... loop
        B A - 1- for ... next
>
>
> b)   B A do I ... loop
        B A dup !p>r - 1- for @p p+ ... next r>p
>
>
> c)   D C do
>          B A do ... I J ... loop
>      loop

        variable j
        D C dup !p>r - 1- for
            B A dup j ! - 1- for
                @p j @ ... p+ 1 j +!
            next r>p
        next
>
>
> d)   B A do ... K +loop
        B A -  K / for ... next
>
>
> e)   D C do
>          B A do ... I J ... K +loop
>      L +loop

        variable j
        D C dup !p>r - K / for
            B A dup j ! L / for
                @p j @ ... K p++ L j +!
            next r>p
        next

>
> f)   B A ?do ... loop
        B A - dup if 1- for ... next then
>
>
> Thanks,
> I.
>
>

Re: [Flashforth-devel] For-next and do-loop practise

[om1zz <om...@vo...>]

Mike, thanks! This should definately be put into you FF User Guide!!

?? d) e): K and L are arbitrary values which are added to the loop
counter
?? not sure about the limits (the number of times it runs through
the loop)

a)   B A do ... loop
B A - 1- for ... next

: testa 10 2 - 1- for 0 . next ; ok <#,ram>
testa 0 0 0 0 0 0 0 ok <#,ram>

b)   B A do I ... loop
B A dup !p>r - 1- for @p p+ ... next r>p

: testb 10 2 dup !p>r - 1- for @p . p+ next r>p ; ok <#,ram>
testb 2 3 4 5 6 7 8 ok <#,ram>

c)   D C do
B A do ... I J ... loop
loop

variable j
D C dup !p>r - 1- for
B A dup j ! - 1- for
@p j @ ... p+ 1 j +!
next r>p
next

variable j
: testc
10 2 dup !p>r - 1- for
10 2 dup j ! - 1- for
@p j @ . . p+ 1 j +!
next r>p
next ; ok <#,ram>
testc  2 2 3 3 4 4 5 5 6 6 7 7 8 8 ok <#,ram>

it shall be probably:
------------------------
variable j
: testc
10 2 dup j ! - 1- for
8 3 dup !p>r - 1- for
@p j @ . . p+  
next r>p
1 j +!
next ;

testc 2 3 2 4 2 5 2 6 3 3 3 4 3 5 3 6 4 3 4 4 4 5 4 
6 5 3 5 4 5 5 5 6 6 3 6 4 6 5 6 6 7 3 7 4 7 5 7 6 8 3 
8 4 8 5 8 6 ok <#,ram>


d)   B A do ... K +loop
B A -  K / for ... next

Issue: Here K is usualy a step of any value (not (B-A/K))

e)   D C do
B A do ... I J ... K +loop
L +loop

variable j
D C dup !p>r - K / for
B A dup j ! L / for
@p j @ ... K p++ L j +!
next r>p
next

Issue: Here K and L are usualy steps of any value (not (B-A/K))

f)   B A ?do ... loop
B A - dup if 1- for ... next then

: testf 10 2 - dup if 1- for 0 . next then ; ok <#,ram>
testf 0 0 0 0 0 0 0 ok <#,ram>

Re: [Flashforth-devel] For-next and do-loop practise

[Mikael N. <mik...@pp...>]

Hi,
Some further thoughts:

a)  B A do ... loop
The case a) cannot be translated. It will execute as f).
f)  B A ?do ... loop

: testa #10 #2 - for r@ . next ;  ok<$,ram>
testa 7 6 5 4 3 2 1 0  ok<$,ram>

b) This will also execute as ?do.
B A ?do i . loop

: testb #10 #2 dup !p>r - for @p . p+ next r>p ;  ok<$,ram>
testb 2 3 4 5 6 7 8 9  ok<$,ram>

/Mike

On 16.6.2011 18:56, om1zz wrote:
> Mike, thanks! This should definately be put into you FF User Guide!!
>
> ?? d) e): K and L are arbitrary values which are added to the loop
> counter
> ?? not sure about the limits (the number of times it runs through
> the loop)
>
> a)   B A do ... loop
> B A - 1- for ... next
>
> : testa 10 2 - 1- for 0 . next ; ok<#,ram>
> testa 0 0 0 0 0 0 0 ok<#,ram>
>
> b)   B A do I ... loop
> B A dup !p>r - 1- for @p p+ ... next r>p
>
> : testb 10 2 dup !p>r - 1- for @p . p+ next r>p ; ok<#,ram>
> testb 2 3 4 5 6 7 8 ok<#,ram>
>
> c)   D C do
> B A do ... I J ... loop
> loop
>
> variable j
> D C dup !p>r - 1- for
> B A dup j ! - 1- for
> @p j @ ... p+ 1 j +!
> next r>p
> next
>
> variable j
> : testc
> 10 2 dup !p>r - 1- for
> 10 2 dup j ! - 1- for
> @p j @ . . p+ 1 j +!
> next r>p
> next ; ok<#,ram>
> testc  2 2 3 3 4 4 5 5 6 6 7 7 8 8 ok<#,ram>
>
> it shall be probably:
> ------------------------
> variable j
> : testc
> 10 2 dup j ! - 1- for
> 8 3 dup !p>r - 1- for
> @p j @ . . p+
> next r>p
> 1 j +!
> next ;
>
> testc 2 3 2 4 2 5 2 6 3 3 3 4 3 5 3 6 4 3 4 4 4 5 4
> 6 5 3 5 4 5 5 5 6 6 3 6 4 6 5 6 6 7 3 7 4 7 5 7 6 8 3
> 8 4 8 5 8 6 ok<#,ram>
>
>
> d)   B A do ... K +loop
> B A -  K / for ... next
>
> Issue: Here K is usualy a step of any value (not (B-A/K))
>
> e)   D C do
> B A do ... I J ... K +loop
> L +loop
>
> variable j
> D C dup !p>r - K / for
> B A dup j ! L / for
> @p j @ ... K p++ L j +!
> next r>p
> next
>
> Issue: Here K and L are usualy steps of any value (not (B-A/K))
>
> f)   B A ?do ... loop
> B A - dup if 1- for ... next then
>
> : testf 10 2 - dup if 1- for 0 . next then ; ok<#,ram>
> testf 0 0 0 0 0 0 0 ok<#,ram>
>
>

Re: [Flashforth-devel] For-next and do-loop practise

[om1zz <om...@vo...>]

Mike, can the "do-loop" cases be summarized, thus we get a guide on
it? I.
> Some further thoughts:
> 
> a)  B A do ... loop
> The case a) cannot be translated. It will execute
> as f).
> f)  B A ?do ... loop
> 
> : testa #10 #2 - for r@ . next ;  ok<$,ram>
> testa 7 6 5 4 3 2 1 0  ok<$,ram>
> 
> b) This will also execute as ?do.
> B A ?do i . loop
> 
> : testb #10 #2 dup !p>r - for @p . p+ next r>p ; 
> ok<$,ram>
> testb 2 3 4 5 6 7 8 9  ok<$,ram>
> 
> /Mike



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