Mutare.Mutators.Relational (mutare v0.1.1)

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Relational/equality operator swaps:

:>   → :>=, :<       :==  → :!=
:>=  → :>,  :<=      :!=  → :==
:<   → :<=, :>       :=== → :!==
:<=  → :<,  :>=      :!== → :===

Ordering operators mutate to both their boundary neighbour and their direction flip (the classic boundary + reversal pair); equality operators flip polarity, and membership (in) flips to not in (the polarity flip for membership, mirroring == → !=). Legal in bodies and when guards.

Not mutated:

  • not in → in is not produced — x not in y parses as not(x in y), which Mutare.Mutators.Logical already strips. For the same reason, an in node that is the direct operand of not/! is left to Logical.
  • An equality operator (==/!=/===/!==) directly under not/! is left to Logical — each is its own exact polarity complement, so !(a != b) ≡ a == b (Logical's strip). The ordering operators are not suppressed there: their boundary/reversal swaps are not the negation complement, so they survive a surrounding negation as genuinely new mutants.

Filterable variants — qualify a # mutare:ignore filter with :label to suppress just one kind (Mutare.Mutator.variants/0): >, >=, <, <=, ==, !=, ===, !==.