Hi, Maarten,
Maarten Koopmans wrote:
>
> ... it responds to a 'rest word, giving you the restof the
> block to be evaluated and the value of the last evaluated expression.
>
> So: eval [ 10 + 10 join "a" "b" rest 20 print "howdy" ]
> >> [ "ab" [ 20 print "howdy"]]
>
> Note that the second item (the rest of the code) is the position in the
> original code, so a ' head on that gives you the original code back.
>
Sort of like iterating DO/NEXT with an additional check for REST ?
>
> Question: is this a thing any of you want despite the performance hit of
> 400% ?
>
I pondered doing something with DO/NEXT a while back, but gave up in
frustration (I hope you're smarter and/or more patient than I ;-) as
I want to be able to write expressions/functions more sophisticated
than a single block, but still have interruptability. For example:
eval [
foreach line read/lines %somefile [
print line
rest
]
]
Or
interruptableFunction: func [aLine [string!]] [
print aLine
doSomethingInteresting aLine
rest
]
eval [
foreach line read/lines %someOtherFile [
interruptableFunction line
]
]
You said "takes a block" so I inferred that things such as the above
(nested blocks, including function evaluation) are currently out of
reach. Am I too pessimistic?
If I have to do all the work of managing e.g. loops and other "control
structures", including functions, I think I'd probably want to just go
ahead and evert the code into a task object (per the article on
REBOLforces) with a STEP method that does some meaningful (but not over
long) piece of work and then saves state and returns control.
-jn-
--
----------------------------------------------------------------------
Joel Neely joelDOTneelyATfedexDOTcom 901-263-4446
Enron Accountingg in a Nutshell: 1c=$0.01=($0.10)**2=(10c)**2=100c=$1
--
To unsubscribe from this list, just send an email to
[EMAIL PROTECTED] with unsubscribe as the subject.
