Dynamic scripted nested array keys?

[Brian Milby]

I guess I should reply to myself and say why this works.  At some point the
feature was added that you could use an array as an index into an array.
The format is a one based ordered array of keys.  So tPath[1] is the first
level key, tPath[2] is the second level, etc.  If you wanted to get
tTree["one"]["two"] then tPath[1]="one" and tPath[2]="two" so you could
just get tTree[tPath].  Since comma is the default path delimiter (which
can be changed), you can use split to turn a path list into a path array.

On Sat, Apr 24, 2021 at 9:26 AM Brian Milby <brian at milby7.com> wrote:

> Easiest way is to use split...
>
> Given a tree widget this will take a path from field 1 and put the value
> at that path in field 2
>
> on mouseUp pMouseButton
>    local tTree, tLoc
>    put the arrayData of widget 1 into tTree
>    put field 1 into tLoc
>    split tLoc by comma
>    put tTree[tLoc] into field 2
> end mouseUp
>
> Thanks,
> Brian
>
> On Sat, Apr 24, 2021 at 9:06 AM Paul Dupuis via use-livecode <
> use-livecode at lists.runrev.com> wrote:
>
>> I have only partially been following this thread, but if you need to
>> find the array 'content' in an arbitrary nested array from a comma
>> delimited path of array keys, recursion is the way to do it:
>>
>> function fetchArrayContentFromPath pArray,pPath
>>    -- pArray is an array
>>    -- pPath is a comma delimited 'path' of array keys to the desired
>> content
>>    local tKey
>>    if pArray is not an array then
>>      return pArray -- I have reached the content, so return that content
>>    else if pPath is empty then
>>      return pArray -- should not happen in a tree widget, but this is if
>> the path ends in an array instead of the content of an array element
>>    else
>>      put item 1 of pPath into tKey -- get the key of element in the
>> currnet path
>>      delete item 1 of pPath        -- remove it from the current path,
>> so the path is the next set of key(s)
>>      return fetchArrayContentFromPath(pArray[tKey],pPath) - recursively
>> fetch the remainig keys from the currnet array element
>>    end if
>> end fetchArrayContentFromPath
>>
>> It will not matter is the 'path' is key1,key1 or
>> key1,key2,key3,key4,key5,key6,key7, or whatever.
>>
>>
>> On 4/24/2021 7:10 AM, Keith Clarke via use-livecode wrote:
>> > Hi folks,
>> > Inspired by Jaque’s (working - thank you!) response to my question
>> “Show Tree widget row contents on hover” I’ve isolated the final piece of
>> that puzzle that leaves me baffled.
>> >
>> > Specifically, can LiveCode accept a dynamically built key for a nested
>> multi-dimensional array? Copy the button script recipe below to see the
>> problem.
>> >
>> > Perhaps the LC array experts here can help explain why Jaque’s
>> hard-wired key definition works but my attempts to replicate this syntax
>> via scripting to support variable depth of arrays  get ignored? Is it my
>> syntax or just the way arrays work in LC…?
>> > on mouseUp pButtonNumber
>> >
>> > # Create a nested array
>> >
>> > put "Content" into tArray["key1"]["key2"]["key3"]["key4"]
>> >
>> >
>> > # Replicate the path response from the Tree widget actionInspect
>> function
>> >
>> > put "key1,key2,key3,key4" into pPath
>> >
>> >
>> > # Jaque's 'hard-wired' array key recipe works!
>> >
>> > answer tArray[item 1 of pPath][item 2 of pPath][item 3 of pPath][item 4
>> of pPath] --returns 'Content'
>> >
>> >
>> > # Replicate Jaque's syntax dynamically
>> >
>> > put the number of items in pPath into tKeyCount
>> >
>> > put empty into iNum
>> >
>> > repeat for each item i in pPath
>> >
>> > add 1 to iNum
>> >
>> > # Try building the full key string
>> >
>> > put "[" & item iNum of pPath & "]"after tKey1
>> >
>> >
>> > # Try building keys string to 'embed' into the regular array key syntax
>> >
>> > put item iNum of pPath after tKey2
>> >
>> > if iNum < tKeyCount then put "][" after tKey2
>> >
>> >
>> > # Try building by each key
>> >
>> > if i is not empty then put "[" & item iNum of pPath & "]" after tArray2
>> >
>> > end repeat
>> >
>> >
>> > # Dynamic tKey1 results
>> >
>> > answer tKey1 -- returns '["key1"]["key2"]["key3"]["key4"]' ...seems
>> 'correct'
>> >
>> > answer tArray & tKey1 -- returns '["key1"]["key2"]["key3"]["key4"]'
>> ...dynamic key definition is not appended to array(?)
>> >
>> >
>> > # Dynamic tKey2 results
>> >
>> > answer tKey2 -- returns '"key1"]["key2"]["key3"]["key4"'
>> >
>> > answer tArray[tKey2] -- returns null ...dynamic key definition is not
>> understood (as first level key)?
>> >
>> >
>> > answer tArray2 -- returns '["key1"]["key2"]["key3"]["key4"]' ...dynamic
>> key definition is not appended to array(?)
>> >
>> > end mouseUp
>> >
>> >
>> > Best,
>> > Keith
>> >
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