REBOL layout: How to create layout words automatically
Using the REBOL/View 2.7.8 Core, I would like to prepare a view layout beforehand by automatically assigning words to various layout items, as in the following example. Instead of
prepared-view: [across
cb1: check
label "Checkbox 1"
cb2: check
label "Checkbox 2"
cb3: check
label "Checkbox 3"
cb4: check
label "Checkbox 4"
]
view layout prepared-view
I would thus like the words cb1
thru cb5
to be created automatically, eg:
prepared-view2: [ across ]
for i 1 4 1 [
cbi: join "cb" i
cbi: join cbi ":"
cbi: join cbi " check"
append prepared-view2 to-block cbi
append prepared-view2 [
label ]
append prepared-view2 to-string join "Checkbox " i
]
view layout prepared-view2
However, while difference prepared-view prepared-view2
shows no differences in the block being parsed ( == []
), the second script leads to an error:
** Script Error: cb1 word has no context
** Where: forever
** Near: new/var: bind to-word :var :var
I've spent hours trying to understand why, and I think somehow the new words need to be bound to the specific context, but I have not yet found any solution to the problem.
What do I need to do?
bind prepared-view2 'view
view layout prepared-view2
creates the correct bindings.
And here's another way to dynamically create layouts
>> l: [ across ]
== [across]
>> append l to-set-word 'check
== [across check:]
>> append l 'check
== [across check: check]
>> append l "test"
== [across check: check "test"]
>> view layout l
And then you can use loops to create different variables to add to your layout.
When you use TO-BLOCK to convert a string to a block, that's a low-level operation that doesn't go through the "ordinary" binding to "default" contexts. All words will be unbound:
>> x: 10
== 10
>> code: to-block "print [x]"
== [print [x]]
>> do code
** Script Error: print word has no context
** Where: halt-view
** Near: print [x]
So when you want to build code from raw strings at runtime whose lookups will work, one option is to use LOAD and it will do something default-ish, and that might work for some code (the loader is how the bindings were made for the code you're running that came from source):
>> x: 10
== 10
>> code: load "print [x]"
== [print [x]]
>> do code
10
Or you can name the contexts/objects explicitly (or by way of an exemplar word bound into that context) and use BIND.
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