TRACE contentslist

Marks the named items for tracing. A message is printed whenever a traced procedure is invoked, giving the actual input values, and whenever a traced procedure executes a STOP or OUTPUT command. A message is printed whenever a new value is assigned to a traced variable using MAKE. A message is printed whenever a new property is given to a traced property list using PPROP.

TRACE does not throw an error if it is asked to trace a procedure, variable, or property list that is not in the workspace, but doing so has no effect. TRACE also does not throw an error if asked to trace a primitive, but this also has no effect.

See the Workspace Queries section for an explanation of the contentslist input.

TO MYPRINT :a
  PRINT :a
END

MYPRINT "Hello
Hello

TRACE "MYPRINT
MYPRINT "Hello
( MYPRINT "Hello )
Hello
UNTRACE "MYPRINT
MYPRINT "Hello
Hello