The targeted functions all take over a second to type-check with my debug
compiler (found using -debug-time-function-bodies). The top two---the two
replaceRange implementations---took about a minute each; this change
knocks them down to 30-40s.
All of this is just breaking expressions apart, and the expressions aren't
even that complicated. I'm concerned that we have a serious performance
regression around the use of lazy(), and I've filed rdar://problem/20875936
so we can look into it. The test change is particularly concerning; there's
a ridiculous difference between 'lazy(...).reverse()' and
'lazy(...).reverse().reverse()'.
No intended functionality change.
Swift SVN r28325
<rdar://20494686>
String itsef should only expose Unicode-correct algorithms, like proper
substring/prefix/suffix search, enumerating words/lines/paragraphs, case
folding etc. Promoting sequence-centric algorithms to methods on String
is not acceptable since it invites users to write wrong code. Thus,
String has to lose its SequenceType conformance.
Nevertheless, we recognize that sometimes it is useful to manipulate the
String contents on lower levels (UTF-8, UTF-16, Unicode scalars,
extended grapheme clusters), for example, when implementing high-level
Unicode operations, so we can't remove low-level operations
altogether. For this reason, String provides nested "views" for the
first three low-level representations, but grapheme clusters were in a
privileged position -- String itself is a collection of grapheme
clusters. We propose to add a characters view that will represent the
String as a collection of Character values.
Swift SVN r28065
