when multimethod

Methods

when(val:Any, pat:Any, new_val:Any) Source: stdlib.ngs:1488

If val matches pat, return new_val.Value(val); otherwise return val. Use instead of older only()

Example

"abcd".mapo(X.when("b", "*"))  # a*cd
"abcd".mapo(F(x) x.when("b", "[$X]"))  # a[b]cd