# `Mutare.Decimal.DefaultDrop`
[🔗](https://github.com/foxbenjaminfox/mutare_decimal/blob/v0.2.1/lib/mutare/decimal/default_drop.ex#L1)

:decimal_default_drop — drops Decimal arguments that refine a default behavior.

The family removes explicit Decimal refinement arguments so the call falls back to the
narrower/default operation:

    Decimal.round(num, places)       # -> Decimal.round(num)
    Decimal.round(num, places, mode) # -> Decimal.round(num, places)
    Decimal.compare(left, right, threshold) # -> Decimal.compare(left, right)
    Decimal.eq?(left, right, threshold)     # -> Decimal.eq?(left, right)

It skips literal arguments that are equivalent to the implicit behavior: zero places,
half-up rounding, and literal zero thresholds.

To avoid duplicates with the numeric literal families, numeric literal places and thresholds
are skipped, even when they differ from the default. Mutare's integer/float literal families
already mutate these to zero, which is equivalent to dropping the argument: round/2 defaults
to zero places, and a zero threshold makes compare/3 behave as compare/2. Dropping a dynamic
refinement expression still produces a mutation, since the numeric literal families do not
replace whole dynamic expressions. To avoid duplicating the round/3 mode drop,
Mutare.Decimal.ModeSwap excludes :half_up as a swap target.

# `variants`

```elixir
@spec variants() :: [atom()]
```

The dropped-argument labels accepted by qualified mutare ignore directives.

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*Consult [api-reference.md](api-reference.md) for complete listing*