Split tags into separate files

Sources/IfTag.swift

@@ -0,0 +1,81 @@
+public class IfNode : NodeType {
+  public let variable:Variable
+  public let trueNodes:[NodeType]
+  public let falseNodes:[NodeType]
+
+  public class func parse(parser:TokenParser, token:Token) throws -> NodeType {
+    let components = token.components()
+    guard components.count == 2 else {
+      throw TemplateSyntaxError("'if' statements should use the following 'if condition' `\(token.contents)`.")
+    }
+    let variable = components[1]
+    var trueNodes = [NodeType]()
+    var falseNodes = [NodeType]()
+
+    trueNodes = try parser.parse(until(["endif", "else"]))
+
+    guard let token = parser.nextToken() else {
+      throw TemplateSyntaxError("`endif` was not found.")
+    }
+
+    if token.contents == "else" {
+      falseNodes = try parser.parse(until(["endif"]))
+      parser.nextToken()
+    }
+
+    return IfNode(variable: variable, trueNodes: trueNodes, falseNodes: falseNodes)
+  }
+
+  public class func parse_ifnot(parser:TokenParser, token:Token) throws -> NodeType {
+    let components = token.components()
+    guard components.count == 2 else {
+      throw TemplateSyntaxError("'ifnot' statements should use the following 'if condition' `\(token.contents)`.")
+    }
+    let variable = components[1]
+    var trueNodes = [NodeType]()
+    var falseNodes = [NodeType]()
+
+    falseNodes = try parser.parse(until(["endif", "else"]))
+
+    guard let token = parser.nextToken() else {
+      throw TemplateSyntaxError("`endif` was not found.")
+    }
+
+    if token.contents == "else" {
+      trueNodes = try parser.parse(until(["endif"]))
+      parser.nextToken()
+    }
+
+    return IfNode(variable: variable, trueNodes: trueNodes, falseNodes: falseNodes)
+  }
+
+  public init(variable:String, trueNodes:[NodeType], falseNodes:[NodeType]) {
+    self.variable = Variable(variable)
+    self.trueNodes = trueNodes
+    self.falseNodes = falseNodes
+  }
+
+  public func render(context: Context) throws -> String {
+    let result = try variable.resolve(context)
+    var truthy = false
+
+    if let result = result as? [Any] {
+      truthy = !result.isEmpty
+    } else if let result = result as? [String:Any] {
+      truthy = !result.isEmpty
+    } else if result != nil {
+      truthy = true
+    }
+
+    context.push()
+    let output:String
+    if truthy {
+      output = try renderNodes(trueNodes, context)
+    } else {
+      output = try renderNodes(falseNodes, context)
+    }
+    context.pop()
+
+    return output
+  }
+}