Migrate project to Xcode 11.1. Support backslash escaping. Approximate support for using link reference definitions.

Author: objecthub

CHANGELOG.md

@@ -1,4 +1,10 @@
 # Changelog
 
+## 0.2 (2019-10-19)
+
+- Implemented support for backslash escaping
+- Added support for using link reference definitions; not fully CommonMark-compliant yet
+- Migrated project to Xcode 11.1
+
 ## 0.1 (2019-08-17)
 - Initial version

MarkdownKit.xcodeproj/project.pbxproj

@@ -14,6 +14,7 @@
 		CC2AF6F7227CD98100BEA420 /* MarkdownBlockTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = CC2AF6F6227CD98100BEA420 /* MarkdownBlockTests.swift */; };
 		CC2AF6F9227CD98100BEA420 /* MarkdownKit.h in Headers */ = {isa = PBXBuildFile; fileRef = CC2AF6EB227CD98100BEA420 /* MarkdownKit.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		CC3E4F532309FE9100C8A3DD /* NSColor.swift in Sources */ = {isa = PBXBuildFile; fileRef = CC3E4F522309FE9100C8A3DD /* NSColor.swift */; };
+		CC5E530C2359FF3A00C72CE2 /* EscapeTransformer.swift in Sources */ = {isa = PBXBuildFile; fileRef = CC5E530B2359FF3A00C72CE2 /* EscapeTransformer.swift */; };
 		CC6988C4227CDF810021C7E1 /* BlockquoteParser.swift in Sources */ = {isa = PBXBuildFile; fileRef = CC6988C3227CDF810021C7E1 /* BlockquoteParser.swift */; };
 		CC6D239822C03CBA00BB1302 /* LinkTransformer.swift in Sources */ = {isa = PBXBuildFile; fileRef = CC6D239722C03CBA00BB1302 /* LinkTransformer.swift */; };
 		CC72627122F318C0001AB6D9 /* main.swift in Sources */ = {isa = PBXBuildFile; fileRef = CC72627022F318C0001AB6D9 /* main.swift */; };
@@ -79,6 +80,7 @@
 		CC2AF6F6227CD98100BEA420 /* MarkdownBlockTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = MarkdownBlockTests.swift; sourceTree = "<group>"; };
 		CC2AF6F8227CD98100BEA420 /* Info.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = Info.plist; sourceTree = "<group>"; };
 		CC3E4F522309FE9100C8A3DD /* NSColor.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = NSColor.swift; sourceTree = "<group>"; };
+		CC5E530B2359FF3A00C72CE2 /* EscapeTransformer.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = EscapeTransformer.swift; sourceTree = "<group>"; };
 		CC6988C3227CDF810021C7E1 /* BlockquoteParser.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = BlockquoteParser.swift; sourceTree = "<group>"; };
 		CC6988C5227CDFB10021C7E1 /* README.md */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = net.daringfireball.markdown; path = README.md; sourceTree = "<group>"; };
 		CC6988C6227CDFB10021C7E1 /* LICENSE */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text; path = LICENSE; sourceTree = "<group>"; };
@@ -249,6 +251,7 @@
 				CC7B603C22AC6AD70092188C /* CodeLinkHtmlTransformer.swift */,
 				CC6D239722C03CBA00BB1302 /* LinkTransformer.swift */,
 				CC7B604022B67F0C0092188C /* EmphasisTransformer.swift */,
+				CC5E530B2359FF3A00C72CE2 /* EscapeTransformer.swift */,
 				CC7B603E22AEFDFF0092188C /* ParserUtil.swift */,
 			);
 			path = Parser;
@@ -328,7 +331,7 @@
 			isa = PBXProject;
 			attributes = {
 				LastSwiftUpdateCheck = 1030;
-				LastUpgradeCheck = 1100;
+				LastUpgradeCheck = 1110;
 				ORGANIZATIONNAME = "Matthias Zenger";
 				TargetAttributes = {
 					CC2AF6E7227CD98100BEA420 = {
@@ -385,6 +388,7 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				CC5E530C2359FF3A00C72CE2 /* EscapeTransformer.swift in Sources */,
 				CC6988C4227CDF810021C7E1 /* BlockquoteParser.swift in Sources */,
 				CC8CBC17227F39C00084683B /* ListItemParser.swift in Sources */,
 				CCB033D2227CDB2F00E1C4DC /* BlockParser.swift in Sources */,
@@ -587,7 +591,7 @@
 					"@executable_path/../Frameworks",
 					"@loader_path/Frameworks",
 				);
-				MARKETING_VERSION = 0.1.3;
+				MARKETING_VERSION = 0.2.0;
 				PRODUCT_BUNDLE_IDENTIFIER = net.objecthub.MarkdownKit;
 				PRODUCT_NAME = "$(TARGET_NAME:c99extidentifier)";
 				SKIP_INSTALL = YES;
@@ -616,7 +620,7 @@
 					"@executable_path/../Frameworks",
 					"@loader_path/Frameworks",
 				);
-				MARKETING_VERSION = 0.1.3;
+				MARKETING_VERSION = 0.2.0;
 				PRODUCT_BUNDLE_IDENTIFIER = net.objecthub.MarkdownKit;
 				PRODUCT_NAME = "$(TARGET_NAME:c99extidentifier)";
 				SKIP_INSTALL = YES;
@@ -665,6 +669,7 @@
 		CC72627222F318C0001AB6D9 /* Debug */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
+				CODE_SIGN_IDENTITY = "-";
 				CODE_SIGN_STYLE = Automatic;
 				DEVELOPMENT_TEAM = C72Z63N8M5;
 				PRODUCT_NAME = "$(TARGET_NAME)";
@@ -675,6 +680,7 @@
 		CC72627322F318C0001AB6D9 /* Release */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
+				CODE_SIGN_IDENTITY = "-";
 				CODE_SIGN_STYLE = Automatic;
 				DEVELOPMENT_TEAM = C72Z63N8M5;
 				PRODUCT_NAME = "$(TARGET_NAME)";

MarkdownKit.xcodeproj/xcshareddata/xcschemes/MarkdownKit.xcscheme

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "1100"
+   LastUpgradeVersion = "1110"
    version = "1.3">
    <BuildAction
       parallelizeBuildables = "YES"

MarkdownKit.xcodeproj/xcshareddata/xcschemes/MarkdownKitProcess.xcscheme

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "1100"
+   LastUpgradeVersion = "1110"
    version = "1.3">
    <BuildAction
       parallelizeBuildables = "YES"

README.md

@@ -3,7 +3,7 @@
 <p>
 <a href="https://developer.apple.com/osx/"><img src="https://img.shields.io/badge/Platform-macOS-blue.svg?style=flat" alt="Platform: macOS" /></a>
 <a href="https://developer.apple.com/swift/"><img src="https://img.shields.io/badge/Language-Swift%205.1-green.svg?style=flat" alt="Language: Swift 5.1" /></a>
-<a href="https://developer.apple.com/xcode/"><img src="https://img.shields.io/badge/IDE-Xcode%2011.0-orange.svg?style=flat" alt="IDE: Xcode 11.0" /></a>
+<a href="https://developer.apple.com/xcode/"><img src="https://img.shields.io/badge/IDE-Xcode%2011.1-orange.svg?style=flat" alt="IDE: Xcode 11.1" /></a>
 <a href="https://raw.github.com/objecthub/swift-markdownkit/master/LICENSE"><img src="http://img.shields.io/badge/License-Apache-lightgrey.svg?style=flat" alt="License: Apache" /></a>
 </p>
 
@@ -191,10 +191,9 @@ where: <source> is either a Markdown file or a directory containing Markdown fil
 
 There are a number of limitations and known issues:
 
-   - The Markdown parser currently does not fully support _link reference definitions_. It is possible to define a
-     link reference, but usage of such references is currently not supported.
-  - Escaping of characters is not handled correctly when generating plain text or when generating HTML or
-    attributed strings.
+  - The Markdown parser currently does not fully support _link reference definitions_ in a CommonMark-compliant
+    fashion. It is possible to define link reference definitions and use them, but for some corner cases, the current
+    implementation behaves differently from the spec.
 
 ## Requirements
 
@@ -203,7 +202,7 @@ The command-line tool can be compiled with the _Swift Package Manager_, so _Xcod
 for that. Similarly, just for compiling the framework and trying the command-line tool in _Xcode_, the
 _Swift Package Manager_ is not needed.
 
-- [Xcode 11.0](https://developer.apple.com/xcode/)
+- [Xcode 11.1](https://developer.apple.com/xcode/)
 - [Swift 5.1](https://developer.apple.com/swift/)
 - [Swift Package Manager](https://swift.org/package-manager/)
 

Sources/MarkdownKit/Info.plist

@@ -15,7 +15,7 @@
 	<key>CFBundlePackageType</key>
 	<string>FMWK</string>
 	<key>CFBundleShortVersionString</key>
-	<string>0.1.3</string>
+	<string>0.2.0</string>
 	<key>CFBundleVersion</key>
 	<string>$(CURRENT_PROJECT_VERSION)</string>
 	<key>NSHumanReadableCopyright</key>

Sources/MarkdownKit/Parser/EscapeTransformer.swift

@@ -0,0 +1,76 @@
+//
+//  EscapeTransformer.swift
+//  MarkdownKit
+//
+//  Created by Matthias Zenger on 18/10/2019.
+//  Copyright © 2019 Google LLC.
+//
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+//  Unless required by applicable law or agreed to in writing, software
+//  distributed under the License is distributed on an "AS IS" BASIS,
+//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//  See the License for the specific language governing permissions and
+//  limitations under the License.
+//
+
+import Foundation
+
+///
+/// An inline transformer which removes backslash escapes.
+///
+public final class EscapeTransformer: InlineTransformer {
+
+  public override func transform(_ fragment: TextFragment,
+                                 from iterator: inout Text.Iterator,
+                                 into res: inout Text) -> TextFragment? {
+    switch fragment {
+      case .text(let str):
+        res.append(fragment: .text(self.resolveEscapes(str)))
+      case .link(let inner, let uri, let title):
+        res.append(fragment: .link(self.transform(inner), uri, self.resolveEscapes(title)))
+      case .image(let inner, let uri, let title):
+        res.append(fragment: .image(self.transform(inner), uri, self.resolveEscapes(title)))
+      default:
+        return super.transform(fragment, from: &iterator, into: &res)
+    }
+    return iterator.next()
+  }
+
+  private func resolveEscapes(_ str: String?) -> String? {
+    if let str = str {
+      return String(self.resolveEscapes(Substring(str)))
+    } else {
+      return nil
+    }
+  }
+
+  private func resolveEscapes(_ str: Substring) -> Substring {
+    guard !str.isEmpty else {
+      return str
+    }
+    var res: String? = nil
+    var i = str.startIndex
+    while i < str.endIndex {
+      if str[i] == "\\" {
+        if res == nil {
+          res = String(str[str.startIndex..<i])
+        }
+        i = str.index(after: i)
+        guard i < str.endIndex else {
+          break
+        }
+      }
+      res?.append(str[i])
+      i = str.index(after: i)
+    }
+    guard res == nil else {
+      return Substring(res!)
+    }
+    return str
+  }
+}

Sources/MarkdownKit/Parser/InlineParser.swift

@@ -30,11 +30,62 @@ public class InlineParser {
   /// Sequence of inline transformers which implement the inline parsing functionality.
   private var inlineTransformers: [InlineTransformer]
 
+  /// Blocks of input document
+  private let block: Block
+
+  /// Link reference declarations
+  public private(set) var linkRefDef: [String : (String, String?)]
+
   /// Initializer
-  init(inlineTransformers: [InlineTransformer.Type]) {
+  init(inlineTransformers: [InlineTransformer.Type], input: Block) {
+    self.block = input
+    self.linkRefDef = [:]
     self.inlineTransformers = []
     for transformerType in inlineTransformers {
-      self.inlineTransformers.append(transformerType.init())
+      self.inlineTransformers.append(transformerType.init(owner: self))
+    }
+  }
+
+  /// Traverses the input block and applies all inline transformers to all text.
+  public func parse() -> Block {
+    // First, collect all link reference definitions
+    self.collectLinkRefDef(self.block)
+    // Second, apply inline transformers
+    return self.parse(self.block)
+  }
+
+  /// Traverses a Markdown block and enters link reference definitions into `linkRefDef`.
+  public func collectLinkRefDef(_ block: Block) {
+    switch block {
+      case .document(let blocks):
+        self.collectLinkRefDef(blocks)
+      case .blockquote(let blocks):
+        self.collectLinkRefDef(blocks)
+      case .list(_, _, let blocks):
+        self.collectLinkRefDef(blocks)
+      case .listItem(_, _, let blocks):
+        self.collectLinkRefDef(blocks)
+      case .referenceDef(let label, let dest, let title):
+        if title.isEmpty {
+          let canonical = label.trimmingCharacters(in: .whitespacesAndNewlines).lowercased()
+          self.linkRefDef[canonical] = (String(dest), nil)
+        } else {
+          var str = ""
+          for line in title {
+            str += line.description
+          }
+          self.linkRefDef[label] = (String(dest), str)
+        }
+      default:
+        break
+    }
+  }
+
+  /// Traverses an array of Markdown blocks and enters link reference definitions
+  /// into `linkRefDef`.
+  public func collectLinkRefDef(_ blocks: Blocks) {
+    for block in blocks {
+      self.collectLinkRefDef(block)
     }
   }
 
@@ -86,8 +137,4 @@ public class InlineParser {
     }
     return res
   }
-
-  public func transform(_ line: Substring) -> Substring {
-    return line
-  }
 }

Sources/MarkdownKit/Parser/InlineTransformer.swift

@@ -28,7 +28,11 @@ import Foundation
 ///
 open class InlineTransformer {
 
-  required public init() {}
+  public unowned let owner: InlineParser
+
+  required public init(owner: InlineParser) {
+    self.owner = owner
+  }
 
   open func transform(_ text: Text) -> Text {
     var res: Text = Text()
@@ -52,12 +56,12 @@ open class InlineTransformer {
         res.append(fragment: .emph(self.transform(inner)))
       case .strong(let inner):
         res.append(fragment: .strong(self.transform(inner)))
-      case .link(let inner, let label, let title):
-        res.append(fragment: .link(self.transform(inner), label, title))
+      case .link(let inner, let uri, let title):
+        res.append(fragment: .link(self.transform(inner), uri, title))
       case .autolink(_):
         res.append(fragment: fragment)
-      case .image(let inner, let label, let title):
-        res.append(fragment: .image(self.transform(inner), label, title))
+      case .image(let inner, let uri, let title):
+        res.append(fragment: .image(self.transform(inner), uri, title))
       case .html(_):
         res.append(fragment: fragment)
       case .delimiter(_, _, _):