Tabbing a block of TLA+ doesn't preserve indentation of conjunct and disjunct lists

Put(t, d) ==
/\ t \notin waitSet
\* The Producer t must not have initiated its termination.
/\ prod[t] = Cardinality(C)
/\ \/ /\ Len(buffer) < B
      /\ buffer' = Append(buffer, d)
      /\ NotifyOther(t)
   \/ /\ Len(buffer) = B
      /\ Wait(t)
/\ UNCHANGED <<prod,cons>>

vs

Put(t, d) ==
    /\ t \notin waitSet
    \* The Producer t must not have initiated its termination.
    /\ prod[t] = Cardinality(C)
    /\ \/ /\ Len(buffer) < B
        /\ buffer' = Append(buffer, d)
        /\ NotifyOther(t)
    \/ /\ Len(buffer) = B
        /\ Wait(t)
    /\ UNCHANGED <<prod,cons>>

Fortunately in this case, SANY caught it:

Parsing file /home/markus/src/TLA/_specs/models/tutorials/BlockingQueueTLA/BlockingQueuePoisonApple.tla
***Parse Error***

  Precedence conflict between ops \lor in block line 124, col 5 to line 124, col 6 of module BlockingQueuePoisonApple and \land.

Residual stack trace follows:
ExtendableExpr starting at line 124, column 8.
ExtendableExpr starting at line 118, column 5.
Expression starting at line 118, column 5.
Definition starting at line 117, column 1.
Module body starting at line 7, column 1.


Fatal errors while parsing TLA+ spec in file BlockingQueuePoisonApple

tla2sany.semantic.AbortException
*** Abort messages: 1

In module BlockingQueuePoisonApple

Could not parse module BlockingQueuePoisonApple from file BlockingQueuePoisonApple.tla


Starting... (2021-07-10 14:43:26)
Error: Parsing or semantic analysis failed.
Finished in 00s at (2021-07-10 14:43:26)

FWIW: The (Eclipse-based) Toolbox does the right thing when tabbing. 😃

[johnyf]

It appears that when the VSCode editor configuration option “Use Tab Stops” is unticked, then a uniform amount of indentation is inserted across a set of selected lines, when pressing the tab key. This editor option is described in VSCode as:

inserting and deleting whitespace follows tab stops

[lemmy]

Given that editor.useTabStops is on by default, our extension should probably raise a warning.