[swift-evolution] Change Request: Make myString.hasPrefix("") and myString.hasSuffix("") return true
michael.peternell at gmx.at
Wed Jul 20 13:42:17 CDT 2016
this should be a bugfix.
> Am 18.07.2016 um 19:36 schrieb Chris Denter via swift-evolution <swift-evolution at swift.org>:
> Hello –
> Currently, the standard library String functions .hasPrefix() and .hasSuffix() will return false when given the empty string as input:
> $ swift
> 1> "".hasPrefix("")
> $R0: Bool = false
> 2> "foo".hasPrefix("")
> $R1: Bool = false
> 3> "foo".hasSuffix("")
> $R2: Bool = false
> This feels unexpected. The reason the methods behave this way seems to be a leaked implementation detail.
> Some languages, such as Python, return True in these cases -- perhaps motivated by the `someSet.contains(emptySet) == true` analogy.
> The ship has sailed for NSString and Foundation, but we might want to bite the bullet and fix this for Swift before 3.0 makes that much harder.
> Thank you so much for your time,
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