Consider pilfering functionality about swift-mode HOT 3 OPEN

Our lexer needs to analyze the type of tokens and required to parse both forward and backward, rather than just skipping forward. It also needs to parse various constructs other than types.

Hiding bodies would be useful, but why not just use hs-hide-all or hs-hide-level? Those functions can handle other types of blocks and parenthesis. For example, swift-hide-bodies doesn't hide let definitions in Parser.swift while hs-hide-level handles parenthesized expressions well.

Besides, swift-hide-bodies needs some improvements:

• swift-skip-type-name doesn't skip those types:

  • Types with attribute: @A B
  • Implicitly unwrapped optional types: Int!
  • Protocol composition types: P & Q
  • Opaque types: some P
  • Explicit existential types: any P
  • Async function types: (Int) async throws -> Int
  • Type names in backticks: `Int`
  • Type names with emoji: 😊

• swift-hide-bodies mishandles:

  • Bare keyword as an identifier:

    class Foo {
      func `deinit`(f: () -> Void) -> Void {
        f()
      }
    }
    
    let foo = Foo()
    // we can use bare keyword as identifier after dot.
    let x = foo.deinit {
      print("aaa")
    }

  • var in case patterns:

    if case var x: Int=1 {
      print("aaa")
    }

    Note that swift-skip-type-name thinks Int=1 is a type name.

swift-hide-doc-comment-detail seems to be nice to incorporate. I'm not sure how to combine codes under Apache License v2.0 and GPLv3, though I know that Apache License v2.0 is compatible with GPLv3.

Other than that, Apple's swift-mode seems to be less accurate while concise and efficient; it doesn't handle those constructs:

• Multiline string literals:

    let x = """
      aaa " aaa
      """
    let y = Foo()

• Extended string literals: #"abc"def"#

• String interpolations: "aaa \(/* " */ 1) bbb"

• Regular expressions.

• Nested multiline comments.

from swift-mode.

from swift-mode.

hs-hide-all hides too much (the methods and properties of every type); I was unable to make hs-hide-level do anything useful in my Swift file.

C-2 M-x hs-hide-level at the beginning of the Parser.swift will show you outline of the file.

? let definitions don’t ever have bodies in Swift. A body is a block surrounded by braces at the top level of a declaration.

Parser.swift has many let bindings with large expression, that is, functionDecl and followings. To grab the outline of the file, it should be hidden.

from swift-mode.