Module mangle 

Swift type manglings, built rather than counted.

A mangled type name is length-prefixed: SwiftUI.ContentTransition is 7SwiftUI17ContentTransitionV, where the 7 and the 17 are the lengths of the two identifiers and the V says it is a struct. Writing those by hand is arithmetic in a string literal, and getting one wrong does not fail to compile — it resolves to nothing, or to the wrong type, at run time. This crate shipped 14decimalDigits for a name thirteen characters long, and found out through a panic in an unrelated modifier.

So the lengths are counted by the compiler’s len() instead of by eye:

swift_type!(SwiftUI.ContentTransition)        // 7SwiftUI17ContentTransitionV
swift_type!(enum SwiftUI.Font.Design)         // 7SwiftUI4FontV6DesignO
swift_type!(opt SwiftUI.Color)                // 7SwiftUI5ColorVSg
swift_type!([SwiftUI.EdgeInsets])             // Say7SwiftUI10EdgeInsetsVG

Symbols — functions, getters, witness tables — are not covered. Their mangling encodes argument types, substitutions and calling conventions, and is read off the export table rather than constructed; see crate::resolve.

Enums

Kind

What kind of nominal type is being named.

Type

A Swift type, as a tree the compressor can walk.

Constants

BOOL

Swift.Bool.

DATE

Foundation.Date — one Double of seconds since the reference date.

DOUBLE

Swift.Double.

INT

Swift.Int.

NEVER

Swift.Never.

STRING

Swift.String.

Functions

again

A SwiftUI type written where the module is already in the substitution table.

array

Array<T>.

bound

A generic type applied to arguments — Binding<Bool> is bound(BINDING, &[BOOL]).

demangle

Turn a mangled name back into something readable, for diagnostics.

existential

A protocol existential — any Error is s5Error_p.

imported

A type imported from Objective-C or C.

modified

ModifiedContent<AnyView, M> — what applying a modifier to an AnyView produces, and so the result type of most of this crate’s bindings.

modified_content

ModifiedContent<AnyView, M> — the result type of most modifiers.

nested

A type nested inside one of the shorthand types, such as String.Index.

nominal

A nominal type, named by its module and the path to it.

opt

T?.

optional

Optional<T>, which is T with Sg after it.

pack

A generic type applied to a parameter pack.

range

Range<T>.

set

Set<T>, which is Sh applied to one argument.

stdlib

A standard-library type with no shorthand, such as Result.

ty

SwiftUI.Name, a struct.

ty_class

SwiftUI.Name, a class.

ty_enum

SwiftUI.Name, an enum.