Improving Swift Tools with libSyntax

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8SJUFB4XJGUGPSNBUUFS

4FNBOUJD"OBMZTJT 1BSTFS -FYFS $PNQJMFS#BTJDT Lexers, Parsers, Code Gen, Oh My!
struct Cat {} [kw_struct, ident("Cat"), l_brace, r_brace] $BU 'SPOUFOE #BDLFOE

.BDIJOF-PXFSJOH 4FNBOUJD"OBMZTJT 1BSTFS -FYFS $PNQJMFS#BTJDT Lexers, Parsers, Code Gen, Oh
My! struct Cat {} [kw_struct, ident("Cat"), l_brace, r_brace] $BU $BU 0QUJNJ[FS 4*-(FO 0101001010100… "OBMZTJT --7.*3(FO 'SPOUFOE #BDLFOE

4XJGU"CTUSBDU4ZOUBY5SFF struct Cat { let name: String }

4XJGU"CTUSBDU4ZOUBY5SFF struct Cat { let name: String } 4USVDU $BU
.FNCFST 1SPQFSUZ OBNF 4USJOH MFU

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MJC4ZOUBY5SFF struct Cat {}

MJC4ZOUBY5SFF struct Cat {} struct Cat { }

5SBOTGPSNJOH4ZOUBY struct Feline {} struct Cat {}

5SBOTGPSNJOH4ZOUBY struct Feline {} struct Cat {} struct Cat {}
struct Cat { }

struct Cat {} struct Cat { } struct Feline {}
struct { } Feline 5SBOTGPSNJOH4ZOUBY struct Feline {} struct Cat {}

(SJUUZ%FUBJMT ↟ 3BX4ZOUBY ↟ 4ZOUBY%BUB ↟ 4ZOUBY/PEFT

3BX4ZOUBY indirect enum RawSyntax { }

3BX4ZOUBY indirect enum RawSyntax { case node(SyntaxKind, [RawSyntax], SourcePresence) }

3BX4ZOUBY indirect enum RawSyntax { case node(SyntaxKind, [RawSyntax], SourcePresence) case
token(TokenKind, Trivia, Trivia, SourcePresence) }

5SJWJB3VMFT ↟ 5SBJMJOH5SJWJB ↟ "UPLFOPXOTUIFUSJWJBBGUFSJUVQUPUIFGJSTUOFXMJOF ↟ -FBEJOH5SJWJB ↟ "UPLFOPXOTUIFUSJWJBCFGPSFJUTUBSUJOHXJUIUIFGJSTUOFXMJOF Two
Simple Rules for Lexing my Beautiful Code

5SJWJB3VMFT Two Simple Rules for Lexing my Beautiful Code }
if x == 6 {

5SJWJB3VMFT Two Simple Rules for Lexing my Beautiful Code if
x == 6 { }

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My Identity

4ZOUBY/PEFT ↟ "TUSVDUGPSFBDILJOEPGOPEF ↟ 5ZQFTBGF"1* ↟ "DDFTTPSTGPSFBDIDIJME ↟ 5SBOTGPSNBUJPONFUIPET public
class IfStmtSyntax: StmtSyntax { var ifKeyword: TokenSyntax { … } func withIfKeyword(_ node: TokenSyntax) -> IfStmtSyntax { … } // … more methods }

4ZOUBY$SFBUJPO"1*T • make"1*T • with"1*T • 4ZOUBY#VJMEFST

make"1*T let returnKeyword = SyntaxFactory.makeReturnKeyword(trailingTrivia: .spaces(1)) let three = SyntaxFactory.makeIntegerLiteralExpr(3)
let returnStmt = SyntaxFactory.makeReturnStmt(returnKeyword: returnKeyword, expression: three) Fully Formed and Ready to Go return 3

with"1*T Fully Formed and Ready to Go let returnHello =
returnStmt.withExpression( SyntaxFactory.makeStringLiteralExpr("Hello")) return "Hello" return 3

4ZOUBY#VJMEFST let structKeyword = SyntaxFactory.makeStructKeyword( trailingTrivia: .spaces(1)) struct Cat {}

4ZOUBY#VJMEFST let structKeyword = SyntaxFactory.makeStructKeyword( trailingTrivia: .spaces(1)) let catID =
SyntaxFactory.makeIdentifier("Cat", trailingTrivia: .spaces(1)) struct Cat {}

4ZOUBY#VJMEFST let structKeyword = SyntaxFactory.makeStructKeyword( trailingTrivia: .spaces(1)) let catID =
SyntaxFactory.makeIdentifier("Cat", trailingTrivia: .spaces(1)) let struct = StructDeclSyntax { builder in builder.useStructKeyword(structKeyword) builder.useName(catID) builder.useLeftBrace(SyntaxFactory.makeLeftBraceToken()) builder.useRightBrace(SyntaxFactory.makeRightBraceToken()) } struct Cat {}

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"VUPDPNQMFUFGSJFOEMZ ↟ 4UBSUUZQJOHSyntaxFactory.makeUPTFFBMMUIF"1*T Always Know What to Do

%FNP Building a Swift formatter in Swift

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5IBOL:PV

Improving Swift Tools with libSyntax

Improving Swift Tools with libSyntax

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