DictionaryStorageMacro.swift

DictionaryStorageMacro.swift

public struct DictionaryStorageMacro: MemberMacro {
    
    public static func expansion(of node: AttributeSyntax,
                                 providingMembersOf declaration: some DeclGroupSyntax,
                                 in context: some MacroExpansionContext
    ) throws -> [DeclSyntax] {
        let stringIdentifier = SimpleTypeIdentifierSyntax(name: .identifier("String"))
        let anyIdentifier = SimpleTypeIdentifierSyntax(name: .keyword(.Any))
        let dictionarySyntax = DictionaryTypeSyntax(leftSquareBracket: .leftSquareBracketToken(),
                                                    keyType: stringIdentifier,
                                                    colon: .colonToken(),
                                                    valueType: anyIdentifier,
                                                    rightSquareBracket: .rightSquareBracketToken())
        let functionParameterSyntax = FunctionParameterSyntax(firstName: .identifier("dictionary"),
                                                              colon: .colonToken(),
                                                              type: dictionarySyntax)
        let functionParameterListSyntax = FunctionParameterListSyntax([functionParameterSyntax])
        let parameterClauseSyntax = ParameterClauseSyntax.init(leftParen: .leftParenToken(),
                                                               parameterList: functionParameterListSyntax,
                                                               rightParen: .rightParenToken())
        let signature = FunctionSignatureSyntax.init(input: parameterClauseSyntax)
        
        let codeBlockItemListSyntax = CodeBlockItemListSyntax.init {
            let exprListSyntax = ExprListSyntax.init {
                let selfIdentifier = IdentifierExprSyntax(identifier: .keyword(.self))
                let memberAccessExprSyntax = MemberAccessExprSyntax(base: selfIdentifier,
                                                                    dot: .periodToken(),
                                                                    name: .identifier("dictionary"))
                let assignmentExprSyntax = AssignmentExprSyntax(assignToken: .equalToken())
                let identifierExprSyntax = IdentifierExprSyntax(identifier: .identifier("dictionary"))
                return [memberAccessExprSyntax,
                        assignmentExprSyntax,
                        identifierExprSyntax]
            }
            let sequenceExprSyntax = SequenceExprSyntax.init(elements: exprListSyntax)
            let codeBlockItemSyntaxItem = CodeBlockItemSyntax.Item.init(sequenceExprSyntax)
            let codeBlockItemSyntax = CodeBlockItemSyntax.init(item: codeBlockItemSyntaxItem)
            return [codeBlockItemSyntax]
        }
        let codeBlockSyntax = CodeBlockSyntax.init(leftBrace: .leftBraceToken(),
                                                   statements: codeBlockItemListSyntax,
                                                   rightBrace: .rightBraceToken())
        
        let initializerDeclSyntax = InitializerDeclSyntax.init(initKeyword: .keyword(.`init`),
                                                               signature: signature,
                                                               body: codeBlockSyntax)
        
        
        let patternBindingListSyntax = PatternBindingListSyntax.init {
            let stringIdentifier = SimpleTypeIdentifierSyntax(name: .identifier("String"))
            let anyIdentifier = SimpleTypeIdentifierSyntax(name: .keyword(.Any))
            let dictionarySyntax = DictionaryTypeSyntax(leftSquareBracket: .leftSquareBracketToken(),
                                                        keyType: stringIdentifier,
                                                        colon: .colonToken(),
                                                        valueType: anyIdentifier,
                                                        rightSquareBracket: .rightSquareBracketToken())
            let typeAnnotationSyntax = TypeAnnotationSyntax.init(colon: TokenSyntax.colonToken(),
                                                                 type: dictionarySyntax)
            let dictionaryIdentifier = IdentifierPatternSyntax.init(identifier: "dictionary")
            let patternBindingSyntax = PatternBindingSyntax.init(pattern: dictionaryIdentifier,
                                                                 typeAnnotation: typeAnnotationSyntax)
            return [patternBindingSyntax]
        }
        let variableDeclSyntax = VariableDeclSyntax.init(bindingKeyword: .keyword(.var),
                                                         bindings: patternBindingListSyntax)
        
        
        return [
            DeclSyntax(initializerDeclSyntax),
            DeclSyntax(variableDeclSyntax),
        ]
    }
}