Hi, I try to get the following behaviour:
test-action: [print "---" probe first iterator]
test-predicate: [print type? list]
forall-records object-list test-predicate test-action
forall-records: func [list predicate action][
do predicate ; just for simple test
; iterate through the whole list of values
; check if the first entry satisfies the predicate
; if so execute the action
forall list [if predicate [action]]
]
I want to provide a predicate and an action that can use the parameters
and local words. Of course the above code fails
** Script Error: list has no value
What I came up with is a not so nice and IMO inflexible solution:
forall-records: func [list predicate action][
if any [none? list empty? action][exit]
; iterate through the whole list of values
; check if the first entry satisfies the predicate
; if so execute the action
forall list [if (predicate first list) [do action]]
]
test-predicate: func [object][
either not none? (select object 'name) [true][false]
]
forall-records object-list :test-predicate test-action
I expect the first problem to be a binding problem. I read through the
bindung stuff provided by Ladislaw but it's really hard... So how can
the concept of C++ iterators, predicates, and functionids be implemented
in Rebol? Did someone already wrote some generic functions for this?
Robert
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