Num.neg constructor
Constrains data to negative numbers (zero excluded).
mal
"malformed", the error message in case of non-numeric input values;
the default value is 'not a number'.
pos
the error message if an input value is positive; the default value
is 'it cannot be positive'.
Implementation
Num.neg({String? mal, String? pos})
: this.max(
0 - double.minPositive,
mal: mal,
large: pos ?? 'it cannot be positive',
);