State Indicator Stack

R←⎕STACK

R is a two-column matrix, with one row per entry in the state indicator.

Column 1 :⎕OR form of user defined functions or operators on the state indicator. Space (⎕UCS 32) for entries that are not user defined functions or operators.

Column 2 :Indication of the type of the item on the stack.

space	user defined function or operator
⍎	execute level
⎕	evaluated input
*	desk calculator level
⎕DQ	in callback function
other	primitive operator

Example

      )SI
#.PLUS[2]*
.
#.MATDIV[4]
#.FOO[1]*
⍎

      ⎕STACK
         *
∇PLUS
         .
∇MATDIV
         *
∇FOO
         ⍎
         *

      ⍴⎕STACK
8 2

      (⍴⎕LC)=1↑⍴⎕STACK
0

Pendent defined functions and operators may be edited in Dyalog APL with no resulting SI damage. However, only the visible definition is changed; the pendent version on the stack is retained until its execution is complete. When the function or operator is displayed, only the visible version is seen. Hence ⎕STACK is a tool which allows the user to display the form of the actual function or operator being executed.

Example

To display the version of MATDIV currently pendent on the stack:

      ⊃⎕STACK[4;1]
     ∇ R←A MATDIV B
[1]   ⍝ Divide matrix A by matrix B
[2]    C←A⌹B
[3]   ⍝ Check accuracy
[4]    D←⌊0.5+A PLUS.TIMES B
     ∇