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Make the IsInjective override accept records and lazy functions #134

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Merged
lemmy merged 1 commit into from
Oct 3, 2026
Merged

Make the IsInjective override accept records and lazy functions #134

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8 changes: 5 additions & 3 deletions modules/tlc2/overrides/Functions.java
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Expand Up @@ -65,9 +65,11 @@ public static BoolValue IsInjective(final Value val) {
if (val instanceof SetOfRcdsValue) {
// Input e.g. [a: 1, b: 2]
return isInjectiveNonDestructive(((SetOfRcdsValue) val).values);
} else if (val instanceof FcnRcdValue) {
// Input e.g. [a |-> 1, b |-> 2]
return isInjectiveNonDestructive(((FcnRcdValue) val).values);
}
final Value fcn = val.toFcnRcd();
if (fcn instanceof FcnRcdValue) {
// Input e.g. [a |-> 1, b |-> 2] or [x \in BOOLEAN |-> x]
return isInjectiveNonDestructive(((FcnRcdValue) fcn).values);
}
throw new EvalException(EC.TLC_MODULE_ONE_ARGUMENT_ERROR,
new String[] { "IsInjective", "function", Values.ppr(val.toString()) });
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7 changes: 7 additions & 0 deletions tests/FunctionsTests.tla
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Expand Up @@ -33,6 +33,12 @@ ASSUME(IsInjective([i \in 0..2 |-> i]))
ASSUME(IsInjective( "a":> [{1,2} -> {3,4}] @@ "b":> [{1,2} -> {3,5}] ))
ASSUME(AssertError("The argument of IsInjective should be a function, but instead it is:\n{}", IsInjective({})))

ASSUME(IsInjective([a |-> 1, b |-> 2]))
ASSUME(~IsInjective([a |-> 1, b |-> 1]))
\* The function constructor is not evaluated to an explicit function in this context.
ASSUME((IF IsInjective([b \in BOOLEAN |-> FALSE]) THEN <<1>> ELSE <<2>>)[1] = 2)
ASSUME((IF IsInjective([b \in BOOLEAN |-> b]) THEN <<1>> ELSE <<2>>)[1] = 1)

\* Assert that Functions#isInjectiveDestructive is side-effect free.
SomeSeq == UNION {[1..m -> {1,2}] : m \in 0..Cardinality({1,2})}
SomeExp == CHOOSE x \in SomeSeq: IsInjective(x) /\ Len(x) > 3
Expand All @@ -43,6 +49,7 @@ ASSUME
IN /\ \A f \in [{0,1,2} -> {0,1,2,3}] : IsInjectivePure(f) = IsInjective(f)
/\ \A f \in [{"a","b","c"} -> {0,1,2,3}] : IsInjectivePure(f) = IsInjective(f)
/\ \A f \in [{0,1,2,3} -> {"a","b","c"}] : IsInjectivePure(f) = IsInjective(f)
/\ \A f \in [a : {0,1,2}, b : {0,1,2}, c : {0,1,2}] : IsInjectivePure(f) = IsInjective(f)

ASSUME FoldFunction(LAMBDA x,y: {x} \cup y, {}, <<1,2,1>>) = {1,2}

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