What is a list ?

From the documentation, a list is a 1 dimensional matrix of space separated items enclosed by brackets.

I've created such a list from a returned Json string, stripping off everything I don't need, and AI tells me it's not a list.

So what is a list then.

PoloBot1.aia

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List Blocks, by Sajal Dutta:
List Blocks On App Inventor

Chapter 19 of the App Inventor book:
http://www.appinventor.org/bookChapters/chapter19.pdf

Displaying a list:
http://ai2.appinventor.mit.edu/reference/other/displaylist.html

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I've created such a list from a returned Json string,

to convert a JSON string into a list, use the JsonTextDecode method from the web component

http://ai2.appinventor.mit.edu/reference/components/connectivity.html#Web

any JsonTextDecode(text jsonText)

Decodes the given JSON encoded value to produce a corresponding AppInventor value. A JSON list [x, y, z] decodes to a list (x y z), A JSON object with name A and value B, (denoted as A:B enclosed in curly braces) decodes to a list ((A B)), that is, a list containing the two-element list (A B).

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A list is a chain of items in memory, each pointing to the next item in the list.

It is not an array, which gets pre-allocated memory to put the items in adjacent locations in memory.

See attached for a dangerous but simple list that will bust the stack if you try to generate a text version of it.

Ouroboros is the Greek legendary snake that survives by eating itself, tail first.

Ouroboros.aia

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