isDynamic (object -- isDynamic)

Inputs

• object: Current stack object whose stable-and-unknown state is tested.

Outputs

• isDynamic: Known Cond result of the current unknownness-and-stability test; it is the same predicate as unknownStable?.

isDynamic tests whether an In-place object is currently stable and has an unknown value. For a non-Meta Struct, every solid field must meet that condition; the predicate is the same as unknownStable? and does not itself forget values or change stability.

This predicate follows the referenced target for known non-NIL Ref objects. It is the same predicate as unknownStable?. Mere lack of compile-time knownness is not enough, so Text, Code, and Meta objects still report FALSE. This includes callable non-NIL Code objects and known NIL Code objects.

Behavior

• An In-place object with unknown contents reports TRUE only while it is stable; an unstable object reports FALSE.
• A fully known In-place object reports FALSE.
• A known non-NIL Ref object reports the unknownStable? result of its target.
• Known NIL Ref objects and unknown Ref objects report FALSE.

Example

{} 0 {} [
  value: 7;
  codeLocal: {} () {} codeRef;
  unknownValue: 0 dynamic;
  unknownText: 0 ("") dynamic @; # an unknown Text
  [] !codeLocal # a non-NIL Code

  "-- same as unknownStable? for In-place values --" printCompilerMessage
  7 known? printStack _:;
  7 isDynamic printStack _:;
  7 unknownStable? printStack _:;
  unknownValue known? printStack _:;
  unknownValue isDynamic printStack _:;
  unknownValue unknownStable? printStack _:;

  "-- same as unknownStable? for references --" printCompilerMessage
  @value isDynamic printStack _:;
  @value unknownStable? printStack _:;
  @value dynamic isDynamic printStack _:;
  @value dynamic unknownStable? printStack _:;
  0nx value addressToReference isDynamic printStack _:; # a NIL Ref
  0nx value addressToReference unknownStable? printStack _:;

  "-- same as unknownStable? for text, code, meta --" printCompilerMessage
  "hi" isDynamic printStack _:;
  "hi" unknownStable? printStack _:;
  unknownText isDynamic printStack _:;
  unknownText unknownStable? printStack _:;
  {} () {} codeRef isDynamic printStack _:;
  {} () {} codeRef unknownStable? printStack _:;
  @codeLocal isDynamic printStack _:;
  @codeLocal unknownStable? printStack _:;
  () isDynamic printStack _:;
  () unknownStable? printStack _:;

  0
] "main" exportFunction

Expected Output During Compilation

-- same as unknownStable? for In-place values --
TRUE
FALSE
FALSE
FALSE
TRUE
TRUE
-- same as unknownStable? for references --
FALSE
FALSE
TRUE
TRUE
FALSE
FALSE
-- same as unknownStable? for text, code, meta --
FALSE
FALSE
FALSE
FALSE
FALSE
FALSE
FALSE
FALSE
FALSE
FALSE

See also

• isDirty builtin (object -- isDirty) Current stack-object instability predicate; exact opposite of stable?.
• dynamic builtin (object -- dynamicValue) Current stack-object forgotten-contents conversion.
• isStatic builtin (object -- isKnown) Historical name of the same current stack-object knownness predicate.
• known? builtin (object -- isKnown) Preferred public name of the same current stack-object knownness predicate.
• stable? builtin (object -- isStable) Current stack-object stability predicate; exact opposite of isDirty.
• unknownStable? builtin (object -- isUnknownStable) Same current stable-and-unknown predicate under a different builtin name.