A user-defined conversion function is an instance method that accepts
an empty tuple and returns a value of the type we're converting to,
has the [conversion] attribute, and is named __conversion. The last of
these restrictions is a temporary hack to work around our inability to
perform a lookup across all extensions for "every function with the
conversion attribute", and shouldn't last too long.
As in C++, we only get one user-defined conversion function. Unlike in
C++, a constructor is not (and cannot) be a conversion function.
Introduce NSString <-> String conversion functions, but leave the
runtime implementations as stubs for Dave to fill in.
Swift SVN r1921
applies to operators whose first parameter is [byref]. Assignments
must return Void, and have their first arguments implicitly treated as
an lvalue.
As part of this, add the various C compound operators (+=, -=, *=, /=,
&=, |=, and ^=) to the standard library.
Swift SVN r1846
qualifier, making sure that variables end up so-qualified by
default. Add a RequalifyExpr to capture the act of adding
qualifiers (to form a supertype) to an l-value.
Swift SVN r1236
- introduce the concept of qualifiers on l-value types
- teach overload resolution and coercion how to drop explicitness
- require explicitness on normal [byref] arguments
- make 'this' [byref(implicit)]
- special-case '&' as a unary operator in the parser to make it
produce an expression which type-checks as turning implicit l-values
into explicit ones.
Obvious missing pieces:
- updating LangRef
- we should really complain about ever trying to rvalue-convert an
explicit l-value
- maybe qualification should play a part in overload resolution
- we should diagnose attempts to declare unary '&' operators
- there's a test case in expressions.swift which suggests my logic is
slightly off
But I am out of time, and these will have to wait.
Swift SVN r1119
it doesn't appear in places it shouldn't. The only limits on
this checking right now is the inadequacy of location information
for types, which is something we ought to fix.
Fix type-checking of byref applications. Fix IR generation
of byref variables. Whole lotta fixin' goin' on.
But hey, byref calls work.
Swift SVN r1111
