Forth 2012: ACTION-OF

Interpretation:

( "<spaces>name" -- xt )

Skip leading spaces and parse name delimited by a space. xt is the execution token that name is set to execute. An ambiguous condition exists if name was not defined by DEFER, or if the name has not been set to execute an xt.

Compilation:

( "<spaces>name" -- )

Skip leading spaces and parse name delimited by a space. Append the run-time semantics given below to the current definition. An ambiguous condition exists if name was not defined by DEFER.

Run-time:

( -- xt )

xt is the execution token that name is set to execute. An ambiguous condition exists if name has not been set to execute an xt.

An ambiguous condition exists if POSTPONE, [COMPILE], ['] or ' is applied to ACTION-OF.

See:

6.2.1173 DEFER, 6.2.1175 DEFER!, 6.2.1177 DEFER@, 6.2.1725 IS.

Implementation:

: ACTION-OF
   STATE @ IF
     POSTPONE ['] POSTPONE DEFER@
   ELSE
     ' DEFER@
   THEN ; IMMEDIATE

Testing:

T{ DEFER defer1 -> }T
T{ : action-defer1 ACTION-OF defer1 ; -> }T

T{ ' * ' defer1 DEFER! -> }T
T{ 2 3 defer1 -> 6 }T
T{ ACTION-OF defer1 -> ' * }T
T{ action-defer1 -> ' * }T

T{ ' + IS defer1 -> }T
T{ 1 2 defer1 -> 3 }T
T{ ACTION-OF defer1 -> ' + }T
T{ action-defer1 -> ' + }T