= (leftValue rightValue -- isEqual)

Inputs

• leftValue: Left operand in the comparison.
• rightValue: Right operand in the comparison.

Outputs

• isEqual: Cond result that is TRUE when the dereferenced objects are equal, and unknown when equality cannot be decided at compile time.

= compares dereferenced objects by value equality.

Supported inputs are values whose dereferenced schemas are same-schema Cond, numeric, or non-NIL Text.

= answers a different question from is and same. Use is for identity-like equality and same for dereferenced schema identity.

Behavior

• If the dereferenced schemas differ, the builtin is invalid. It does not return FALSE.
• Ref objects are dereferenced before comparison. Different Ref objects to equal-valued targets therefore make = return TRUE even when is returns FALSE.
• Known Text objects compare by their UTF-8 contents.
• If both dereferenced objects are known, the result is known at compile time.
• If either dereferenced object is unknown, the result is an unknown Cond.
• A known NIL Text input is invalid.

Known issue: when either Text operand is unknown, = compares only data pointers and ignores byte lengths and contents; keep Text values known before using = for content equality. For run-time Text, compare String views instead: apply makeStringView to both operands, then use =.

Example

{} 0 {} [
  condValue: TRUE dynamic;
  first: 7;
  second: 7;
  numberValue: 0 dynamic;
  textValue: 0 ("") dynamic @; # an unknown Text

  "-- cond --" printCompilerMessage
  TRUE TRUE = printStack _:;
  TRUE FALSE = printStack _:;
  condValue TRUE = printStack _:;

  "-- numbers compare by value --" printCompilerMessage
  7 7 = printStack _:;
  7 8 = printStack _:;

  "-- references are dereferenced first --" printCompilerMessage
  @first @second = printStack _:;
  @first @second is printStack _:;

  "-- unknown int32 --" printCompilerMessage
  numberValue 7 = printStack _:;

  "-- text --" printCompilerMessage
  "alpha" "alpha" = printStack _:;
  "alpha" "beta" = printStack _:;

  "-- unknown text --" printCompilerMessage
  textValue "alpha" = printStack _:;

  0
] "main" exportFunction

Expected Output During Compilation

-- cond --
TRUE
FALSE
Cond
-- numbers compare by value --
TRUE
FALSE
-- references are dereferenced first --
TRUE
FALSE
-- unknown int32 --
Cond
-- text --
TRUE
FALSE
-- unknown text --
Cond

See also

• < builtin (leftValue rightValue -- isLess) Tests whether the left dereferenced object is less than the right one for supported same-schema numeric or known Text objects.
• > builtin (leftValue rightValue -- isGreater) Tests whether the left dereferenced object is greater than the right one for supported same-schema numeric or known Text objects.
• is builtin (leftValue rightValue -- isIdentityLike) Tests identity-like equality for references, Text, and Code objects of the same dereferenced schema; In-place objects of the same schema still give FALSE.
• same builtin (leftSchema rightSchema -- isSameSchema) Tests whether two dereferenced schemas are exactly the same; this is schema equality only, not runtime-value equality.