Convert Token from enum to struct (#256)

* convert Token from enum to struct

* private setter for components

* updated CHANGELOG

CHANGELOG.md

@@ -20,7 +20,9 @@ _None_
 
 ### Internal Changes
 
-_None_
+- `Token` type converted to struct to allow computing token components only once.  
+  [Ilya Puchka](https://github.com/ilyapuchka)
+  [#256](https://github.com/stencilproject/Stencil/pull/256)
 
 
 ## 0.13.1

Sources/FilterTag.swift

@@ -4,7 +4,7 @@ class FilterNode : NodeType {
   let token: Token?
 
   class func parse(_ parser: TokenParser, token: Token) throws -> NodeType {
-    let bits = token.components()
+    let bits = token.components
 
     guard bits.count == 2 else {
       throw TemplateSyntaxError("'filter' tag takes one argument, the filter expression")

Sources/ForTag.swift

@@ -9,7 +9,7 @@ class ForNode : NodeType {
   let token: Token?
 
   class func parse(_ parser:TokenParser, token:Token) throws -> NodeType {
-    let components = token.components()
+    let components = token.components
 
     func hasToken(_ token: String, at index: Int) -> Bool {
       return components.count > (index + 1) && components[index] == token

Sources/IfTag.swift

@@ -240,7 +240,7 @@ class IfNode : NodeType {
   let token: Token?
 
   class func parse(_ parser: TokenParser, token: Token) throws -> NodeType {
-    var components = token.components()
+    var components = token.components
     components.removeFirst()
 
     let expression = try parseExpression(components: components, tokenParser: parser, token: token)
@@ -251,7 +251,7 @@ class IfNode : NodeType {
 
     var nextToken = parser.nextToken()
     while let current = nextToken, current.contents.hasPrefix("elif") {
-      var components = current.components()
+      var components = current.components
       components.removeFirst()
       let expression = try parseExpression(components: components, tokenParser: parser, token: current)
 
@@ -273,7 +273,7 @@ class IfNode : NodeType {
   }
 
   class func parse_ifnot(_ parser: TokenParser, token: Token) throws -> NodeType {
-    var components = token.components()
+    var components = token.components
     guard components.count == 2 else {
       throw TemplateSyntaxError("'ifnot' statements should use the following syntax 'ifnot condition'.")
     }

Sources/Include.swift

@@ -7,7 +7,7 @@ class IncludeNode : NodeType {
   let token: Token?
 
   class func parse(_ parser: TokenParser, token: Token) throws -> NodeType {
-    let bits = token.components()
+    let bits = token.components
 
     guard bits.count == 2 || bits.count == 3 else {
       throw TemplateSyntaxError("""

Sources/Inheritence.swift

@@ -53,7 +53,7 @@ class ExtendsNode : NodeType {
   let token: Token?
 
   class func parse(_ parser: TokenParser, token: Token) throws -> NodeType {
-    let bits = token.components()
+    let bits = token.components
 
     guard bits.count == 2 else {
       throw TemplateSyntaxError("'extends' takes one argument, the template file to be extended")
@@ -124,7 +124,7 @@ class BlockNode : NodeType {
   let token: Token?
 
   class func parse(_ parser: TokenParser, token: Token) throws -> NodeType {
-    let bits = token.components()
+    let bits = token.components
 
     guard bits.count == 2 else {
       throw TemplateSyntaxError("'block' tag takes one argument, the block name")
@@ -163,7 +163,7 @@ class BlockNode : NodeType {
     var childContext: [String: Any] = [BlockContext.contextKey: blockContext]
 
     if let blockSuperNode = child.nodes.first(where: {
-      if case .variable(let variable, _)? = $0.token, variable == "block.super" { return true }
+      if let token = $0.token, case .variable = token.kind, token.contents == "block.super" { return true }
       else { return false}
     }) {
       do {

Sources/Node.swift

@@ -62,7 +62,7 @@ public class VariableNode : NodeType {
   let elseExpression: Resolvable?
 
   class func parse(_ parser:TokenParser, token:Token) throws -> NodeType {
-    var components = token.components()
+    var components = token.components
 
     func hasToken(_ token: String, at index: Int) -> Bool {
       return components.count > (index + 1) && components[index] == token

Sources/NowTag.swift

@@ -9,7 +9,7 @@ class NowNode : NodeType {
   class func parse(_ parser:TokenParser, token:Token) throws -> NodeType {
     var format:Variable?
 
-    let components = token.components()
+    let components = token.components
     guard components.count <= 2 else {
       throw TemplateSyntaxError("'now' tags may only have one argument: the format string.")
     }

Sources/Parser.swift

@@ -1,6 +1,6 @@
 public func until(_ tags: [String]) -> ((TokenParser, Token) -> Bool) {
   return { parser, token in
-    if let name = token.components().first {
+    if let name = token.components.first {
       for tag in tags {
         if name == tag {
           return true
@@ -36,9 +36,9 @@ public class TokenParser {
     while tokens.count > 0 {
       let token = nextToken()!
 
-      switch token {
+      switch token.kind {
-      case .text(let text, _):
+      case .text:
-        nodes.append(TextNode(text: text))
+        nodes.append(TextNode(text: token.contents))
       case .variable:
         try nodes.append(VariableNode.parse(self, token: token))
       case .block:
@@ -47,7 +47,7 @@ public class TokenParser {
           return nodes
         }
 
-        if let tag = token.components().first {
+        if let tag = token.components.first {
           do {
             let parser = try findTag(name: tag)
             let node = try parser(self, token)

Sources/Tokenizer.swift

@@ -71,47 +71,53 @@ public struct SourceMap: Equatable {
   }
 }
 
-public enum Token : Equatable {
+public class Token: Equatable {
+  public enum Kind: Equatable {
     /// A token representing a piece of text.
-  case text(value: String, at: SourceMap)
+    case text
-
     /// A token representing a variable.
-  case variable(value: String, at: SourceMap)
+    case variable
-
     /// A token representing a comment.
-  case comment(value: String, at: SourceMap)
+    case comment
-
     /// A token representing a template block.
-  case block(value: String, at: SourceMap)
+    case block
+  }
+  
+  public let contents: String
+  public let kind: Kind
+  public let sourceMap: SourceMap
   
   /// Returns the underlying value as an array seperated by spaces
-  public func components() -> [String] {
+  public private(set) lazy var components: [String] = self.contents.smartSplit()
-    switch self {
+  
-    case .block(let value, _),
+  init(contents: String, kind: Kind, sourceMap: SourceMap) {
-         .variable(let value, _),
+    self.contents = contents
-         .text(let value, _),
+    self.kind = kind
-         .comment(let value, _):
+    self.sourceMap = sourceMap
-      return value.smartSplit()
-    }
   }
   
-  public var contents: String {
+  /// A token representing a piece of text.
-    switch self {
+  public static func text(value: String, at sourceMap: SourceMap) -> Token {
-    case .block(let value, _),
+    return Token(contents: value, kind: .text, sourceMap: sourceMap)
-         .variable(let value, _),
-         .text(let value, _),
-         .comment(let value, _):
-      return value
-    }
   }
 
-  public var sourceMap: SourceMap {
+  /// A token representing a variable.
-    switch self {
+  public static func variable(value: String, at sourceMap: SourceMap) -> Token {
-    case .block(_, let sourceMap),
+    return Token(contents: value, kind: .variable, sourceMap: sourceMap)
-         .variable(_, let sourceMap),
-         .text(_, let sourceMap),
-         .comment(_, let sourceMap):
-      return sourceMap
   }
+
+  /// A token representing a comment.
+  public static func comment(value: String, at sourceMap: SourceMap) -> Token {
+    return Token(contents: value, kind: .comment, sourceMap: sourceMap)
   }
+
+  /// A token representing a template block.
+  public static func block(value: String, at sourceMap: SourceMap) -> Token {
+    return Token(contents: value, kind: .block, sourceMap: sourceMap)
+  }
+  
+  public static func == (lhs: Token, rhs: Token) -> Bool {
+    return lhs.contents == rhs.contents && lhs.kind == rhs.kind && lhs.sourceMap == rhs.sourceMap
+  }
+
 }

Tests/StencilTests/TokenSpec.swift

@@ -7,7 +7,7 @@ class TokenTests: XCTestCase {
     describe("Token") {
       $0.it("can split the contents into components") {
         let token = Token.text(value: "hello world", at: .unknown)
-        let components = token.components()
+        let components = token.components
 
         try expect(components.count) == 2
         try expect(components[0]) == "hello"
@@ -16,7 +16,7 @@ class TokenTests: XCTestCase {
 
       $0.it("can split the contents into components with single quoted strings") {
         let token = Token.text(value: "hello 'kyle fuller'", at: .unknown)
-        let components = token.components()
+        let components = token.components
 
         try expect(components.count) == 2
         try expect(components[0]) == "hello"
@@ -25,7 +25,7 @@ class TokenTests: XCTestCase {
 
       $0.it("can split the contents into components with double quoted strings") {
         let token = Token.text(value: "hello \"kyle fuller\"", at: .unknown)
-        let components = token.components()
+        let components = token.components
 
         try expect(components.count) == 2
         try expect(components[0]) == "hello"