AST1.swift

//: Playground - noun: a place where people can play

import Cocoa

struct AST {
    let declarations: [Statement]
}

enum Statement {
    case expression(Expression)
    case declaration(Declaration)
    case loop(LoopStatement)
    case branch(BranchStatement)
    case labeled(LabeledStatement)
    case controlTransfer(ControlTransferStatement)
    case `defer`(DeferStatement)
    case `do`(DoStatement)
    case compilerControl(CompilerControlStatement)
}

extension Statement {
    var isExpression: Bool {
        if case .expression = self { return true }
        else { return false }
    }
    
    var isDeclaration: Bool {
        if case .declaration = self { return true }
        else { return false }
    }
    
    var isLoopStatement: Bool {
        if case .loop = self { return true }
        else { return false }
    }
    
    var isBranchStatement: Bool {
        if case .branch = self { return true }
        else { return false }
    }
    
    var isLabeledStatement: Bool {
        if case .labeled = self { return true }
        else { return false }
    }
    
    var isControlTransferStatement: Bool {
        if case .controlTransfer = self { return true }
        else { return false }
    }
    
    var isDeferStatement: Bool {
        if case .defer = self { return true }
        else { return false }
    }
    
    var isDoStatement: Bool {
        if case .do = self { return true }
        else { return false }
    }
    
    var isCompilerControlStatement: Bool {
        if case .compilerControl = self { return true }
        else { return false }
    }
}

struct Expression {}
struct Declaration {}
struct LoopStatement {}
struct BranchStatement {}
struct LabeledStatement {}
struct ControlTransferStatement {}
struct DeferStatement {}
struct DoStatement {}
struct CompilerControlStatement {}

func numberOfIfs(in ast: AST) -> Int {
    return ast.declarations.filter { $0.isBranchStatement }.count
}