The existing literals are both few and pretty foundational to programming, so I don't mind them being slightly "magical". Rather than introducing another dozen "magic" types, wouldn't it be better to allow custom literal types, and have all these types use that system?
- Dave Sweeris > On Jul 10, 2016, at 22:48, Erica Sadun via swift-evolution > <[email protected]> wrote: > > This is purely additive and would not be eligible for Swift 3. > gist: https://gist.github.com/erica/c92f6ab115af89d5c4b9161487df6a3c > > -- E > > Extending Swift Literals > Proposal: TBD > Author: Erica Sadun > Status: TBD > Review manager: TBD > Introduction > > This proposal expands Swift's language literals to include common > cross-platform concepts that need not require. > > Motivation > > A Swift literal represents a fixed value in source code. A literal can be a > string, a number (for example an integer), a compound value (such as an > array), or one of several predefined "playground" literals including colors, > resource file paths, and resource images. > > Swift literals do not have types. They are universal representations that are > evaluated and their types inferred from the context in which they are used. > Because their nature is typeless, the same color literal can initialize > UIColor, NSColor, and SKColor instances. The type cannot be inferred from the > source without the context of its destination. > > let color = #colorLiteral(red: 0.8100712299, green: 0.1511939615, blue: > 0.4035313427, alpha: 1) > Detailed Design > > Namespace redesign > Kind Literal Parameters > Color `#literal.color(red:, green:, blue:, alpha:)` floating point values > Image `#literal.image(resourceName:)` String with resource name > File `#literal.file(resourceName:)` String with resource name > General > Kind Literal Parameters > Sound `#literal.audio(resourceName:)` String with resource name > URL `#literal.url(string:)`, `#literal.url(filePath:)` String with > resource location > Font `#literal.font(face:, size:)` string, floating point > Date `#literal.date(timeInterval:)` floating point offset from Unix epoch > Unicode `#literal.unicode(name:)` Official unicode name, e.g. > `#literal.unicode(name:"DOG FACE")` > Geometry > Kind Literal Parameters > Point `#literal.point(x:, y:)`, `#literal.point(x:, y:, z:)`, > `#literal.point(x:, y:, z:, w:)` floating point values > Vector `#literal.vector(dx:, dy:)`, `#literal.vector(dx:, dy:, dz:)`, > `#literal.vector(dx:, dy:, dz:, dw:)` floating point > Size `#literal.size(width:, height:)`, `#literal.size(width:, height:, > depth:)` floating point > Rect `#literal.rect(x:, y:, width:, height:)` floating point > Affine Transform `#literal.affineTransform(a:,b:,c:,d:,tx:,ty:)`, > `#literal.affineTransform(translateX:, translateY:)`, > `#literal.affineTransform(scaleY:, scaleY:)`, > `#literal.affineTransform(rotation:)`, floating point > Bezier Path `#literal.bezier("M92.21,24.29H75L73,17a8.32,8.32, > 0,0,0-8.27-6.74H34.55A7.69,7.69,0,0,0,27,16.6l-2.08 4z")` String with SVG > path notation > Not included: > > Attributed Strings: I would like to see a way to define attributed strings > (using some system like CSS/HTML) but could not think up a simple > representation similar to the others mentioned in the preceding table. > > JSON Literals: Again, probably too complex and possibly not worth their > weight. If they could exist, they'd have to be imported via a resource or URL > and transformed to a local type. > > Impact on Existing Code > > This proposal is purely additive. > > Alternatives Considered > > Using distinct literal names without subsuming them into a namespaced > umbrella. > _______________________________________________ > swift-evolution mailing list > [email protected] > https://lists.swift.org/mailman/listinfo/swift-evolution
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