[TEAL] Extra documentation

[mcalancea]

This issue is for documenting TEAL behavior which is insufficiently explained in the official docs. The proper place for this is the wiki, but this implies a larger refactoring of it, which we will do in-between audits. My recommendation is that we tag items with source and timestamp where possible.

[geo2a]

gtxns ApplicationArgs 0 silently compiles to gtxnsa ApplicationArgs 0

The gtxns f opcode is used to access a scalar filed of a transaction in the group. For accessing the array fields, like ApplicationArgs, the gtxnsa f i opcode is supposed to be used. However, the TEAL assembler of go-algorand compiles the uses of gtxns with two immediate arguments into gtxnsa, see the implementation of the assembleGtxns function.

For additional context, see this comment by @jannotti: algorand/go-algorand#2847 (review)

Using gtxns f like that should be considered invalid syntax, and that's what our TEAL semantics in K does. Anyway, this behavior must be documented in the TEAL docs.

[geo2a]

When creating an application, the creator can opt-in straight away

@nwatson22 has discovered the fact that when an ApplicationCall transaction with ApplicationID == 0 is submitted (app creation), the creator account can specify OnCompletion == OptIn and become opted-in upon acceptance of the creation transaction.

This behavior is not documented in Algrorand Developer Documentation, but that's what go-algorand does.

[jannotti]

Not only that, I believe it can be instantly deleted.

…

On Fri, Sep 30, 2022, 4:43 AM Georgy Lukyanov ***@***.***> wrote: When creating an application, the creator can opt-in straight away @nwatson22 <https://github.com/nwatson22> has discovered the fact that when an ApplicationCall transaction with ApplicationID == 0 is submitted (app creation), the creator account can specify OnCompletion == OptIn and become opted-in upon acceptance of the creation transaction. This behavior is not documented in Algrorand Developer Documentation, but that's what go-algorand does. — Reply to this email directly, view it on GitHub <#12 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AADL7TZVNR7J3V3H6NTIGQDWA2R2LANCNFSM5P6CGLVQ> . You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>