# `Mutare.Duration`
[🔗](https://github.com/foxbenjaminfox/mutare/blob/v0.2.1/lib/mutare/duration.ex#L1)

Parse a human duration string (`"10m"`, `"90s"`, `"1h30m"`) into milliseconds.

Used by the `:time_budget` option (`--time-budget`) — a wall-clock budget for the
per-mutant phase (see `Mutare.Runner`). The grammar is deliberately tiny: one or
more `<integer><unit>` segments, units `h`/`m`/`s`, in descending order, each
optional but **at least one required**. Any non-negative integer is allowed in a
segment (so `"90s"` and `"1h90m"` are fine — there is no 0–59 range check), and the
total must be **positive**.

A bare number with no unit (`"600"`) is rejected — the unit would be ambiguous — as
is any other malformed input (wrong order, an unknown unit, a unit with no number).
The parser never guesses; callers get an `{:error, reason}` they can surface verbatim.

    iex> Mutare.Duration.parse("1h30m")
    {:ok, 5_400_000}

    iex> Mutare.Duration.parse("90s")
    {:ok, 90_000}

    iex> match?({:error, _}, Mutare.Duration.parse("600"))
    true

    iex> match?({:error, _}, Mutare.Duration.parse("30s10m"))
    true

# `parse`

```elixir
@spec parse(term()) :: {:ok, pos_integer()} | {:error, String.t()}
```

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