In UTF-8 decoder:
- implement U+FFFD insertion according to the recommendation given in the
Unicode spec. This required changing the decoder to become stateful, which
significantly increased complexity due to the need to maintain an internal
buffer.
- reject invalid code unit sequences properly instead of crashing rdar://16767868
- reject overlong sequences rdar://16767911
In stdlib:
- change APIs that assume that UTF decoding can never fail to account for
possibility of errors
- fix a bug in UnicodeScalarView that could cause a crash during backward
iteration if U+8000 is present in the string
- allow noncharacters in UnicodeScalar. They are explicitly allowed in the
definition of "Unicode scalar" in the specification. Disallowing noncharacters
in UnicodeScalar prevents actually using these scalar values as internal
special values during string processing, which is exactly the reason why they
are reserved in the first place.
- fix a crash in String.fromCString() that could happen if it was passed a null
pointer
In Lexer:
- allow noncharacters in string literals. These Unicode scalar values are not
allowed to be exchanged externally, but it is totally reasonable to have them
in literals as long as they don't escape the program. For example, using
U+FFFF as a delimiter and then calling str.split("\uffff") is completely
reasonable.
This is a lot of changes in a single commit; the primary reason why they are
lumped together is the need to change stdlib APIs to account for the
possibility of UTF decoding failure, and this has long-reaching effects
throughout stdlib where these APIs are used.
Swift SVN r19045
This is all goodness, and eliminates a major source of implicit conversions.
One thing this regresses on though, is that we now reject "x == nil" where
x is an option type and the element of the optional is not Equtatable. If
this is important, there are ways to enable this, but directly testing it as
a logic value is more straight-forward.
This does not include support for pattern matching against nil, that will be
a follow on patch.
Swift SVN r18918
Many changes in how we're presenting the NSString APIs on String, most
notably that we now traffic in String.Index and Range<String.Index>
rather than Int and NSRange. Also we present NSString initializers that
can fail only as factory functions, and factory functions that can't
fail only as init functions.
About 25% of the API changes here have been reviewd by the Foundation
guys, and testing is, as it has always been, admittedly spotty. Dmitri
is going to be writing some more comprehensive tests.
Swift SVN r18553
String interpolation invokes convertFromStringInterpolationSegment() function
now. There is no need to add extensions to String to allow custom types to
participate in string interpolation. Just implementing Printable will do the
right thing.
Swift SVN r18104
