WIP: AttributedStringVisitor

Down.xcodeproj/project.pbxproj

@@ -88,6 +88,7 @@
 		EEEBEE6B225D2B2200AE438D /* Link.swift in Sources */ = {isa = PBXBuildFile; fileRef = EEEBEE6A225D2B2200AE438D /* Link.swift */; };
 		EEEBEE6D225D2B3200AE438D /* Image.swift in Sources */ = {isa = PBXBuildFile; fileRef = EEEBEE6C225D2B3200AE438D /* Image.swift */; };
 		EEEBEE70225D2B9D00AE438D /* DebugVisitor.swift in Sources */ = {isa = PBXBuildFile; fileRef = EEEBEE6F225D2B9D00AE438D /* DebugVisitor.swift */; };
+		EEEBEE72225D2F9200AE438D /* AttributedStringVisitor.swift in Sources */ = {isa = PBXBuildFile; fileRef = EEEBEE71225D2F9200AE438D /* AttributedStringVisitor.swift */; };
 		EEF1376F2259E53400D7DDE0 /* Node.swift in Sources */ = {isa = PBXBuildFile; fileRef = EEF1376E2259E53400D7DDE0 /* Node.swift */; };
 		EEF137712259E7E700D7DDE0 /* Vistor.swift in Sources */ = {isa = PBXBuildFile; fileRef = EEF137702259E7E700D7DDE0 /* Vistor.swift */; };
 /* End PBXBuildFile section */
@@ -239,6 +240,7 @@
 		EEEBEE6A225D2B2200AE438D /* Link.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Link.swift; sourceTree = "<group>"; };
 		EEEBEE6C225D2B3200AE438D /* Image.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Image.swift; sourceTree = "<group>"; };
 		EEEBEE6F225D2B9D00AE438D /* DebugVisitor.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = DebugVisitor.swift; sourceTree = "<group>"; };
+		EEEBEE71225D2F9200AE438D /* AttributedStringVisitor.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AttributedStringVisitor.swift; sourceTree = "<group>"; };
 		EEF1376E2259E53400D7DDE0 /* Node.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Node.swift; sourceTree = "<group>"; };
 		EEF137702259E7E700D7DDE0 /* Vistor.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Vistor.swift; sourceTree = "<group>"; };
 /* End PBXFileReference section */
@@ -424,13 +426,6 @@
 			isa = PBXGroup;
 			children = (
 				EEF1376E2259E53400D7DDE0 /* Node.swift */,
-				EEEBEE60225D2AC000AE438D /* Code.swift */,
-				EEEBEE62225D2AD400AE438D /* HtmlInline.swift */,
-				EEEBEE64225D2AE800AE438D /* CustomInline.swift */,
-				EEEBEE66225D2AF900AE438D /* Emphasis.swift */,
-				EEEBEE68225D2B1200AE438D /* Strong.swift */,
-				EEEBEE6A225D2B2200AE438D /* Link.swift */,
-				EEEBEE6C225D2B3200AE438D /* Image.swift */,
 				EEEBEE46225D298D00AE438D /* Document.swift */,
 				EEEBEE48225D29C200AE438D /* BlockQuote.swift */,
 				EEEBEE4A225D29D800AE438D /* List.swift */,
@@ -444,6 +439,13 @@
 				EEEBEE5A225D2A7E00AE438D /* Text.swift */,
 				EEEBEE5C225D2A8F00AE438D /* SoftBreak.swift */,
 				EEEBEE5E225D2AA700AE438D /* LineBreak.swift */,
+				EEEBEE60225D2AC000AE438D /* Code.swift */,
+				EEEBEE62225D2AD400AE438D /* HtmlInline.swift */,
+				EEEBEE64225D2AE800AE438D /* CustomInline.swift */,
+				EEEBEE66225D2AF900AE438D /* Emphasis.swift */,
+				EEEBEE68225D2B1200AE438D /* Strong.swift */,
+				EEEBEE6A225D2B2200AE438D /* Link.swift */,
+				EEEBEE6C225D2B3200AE438D /* Image.swift */,
 			);
 			path = Nodes;
 			sourceTree = "<group>";
@@ -453,6 +455,7 @@
 			children = (
 				EEF137702259E7E700D7DDE0 /* Vistor.swift */,
 				EEEBEE6F225D2B9D00AE438D /* DebugVisitor.swift */,
+				EEEBEE71225D2F9200AE438D /* AttributedStringVisitor.swift */,
 			);
 			path = Visitors;
 			sourceTree = "<group>";
@@ -649,6 +652,7 @@
 				8A569F741E6B3EDE008BE2AC /* DownXMLRenderable.swift in Sources */,
 				8A569F6B1E6B3ED9008BE2AC /* utf8.c in Sources */,
 				8A569F791E6B3EE7008BE2AC /* DownOptions.swift in Sources */,
+				EEEBEE72225D2F9200AE438D /* AttributedStringVisitor.swift in Sources */,
 				EEEBEE4B225D29D800AE438D /* List.swift in Sources */,
 				EEEBEE57225D2A6200AE438D /* Heading.swift in Sources */,
 				8A569F601E6B3ED9008BE2AC /* latex.c in Sources */,

Source/AST/Visitors/AttributedStringVisitor.swift

@@ -0,0 +1,160 @@
+//
+//  AttributedStringVisitor.swift
+//  Down
+//
+//  Created by John Nguyen on 09.04.19.
+//
+
+import Foundation
+
+protocol Styler {
+    func style(document str: NSMutableAttributedString)
+    func style(blockQuote str: NSMutableAttributedString)
+    func style(list str: NSMutableAttributedString)
+    func style(item str: NSMutableAttributedString)
+    func style(codeBlock str: NSMutableAttributedString)
+    func style(htmlBlock str: NSMutableAttributedString)
+    func style(customBlock str: NSMutableAttributedString)
+    func style(paragraph str: NSMutableAttributedString)
+    func style(heading str: NSMutableAttributedString)
+    func style(thematicBreak str: NSMutableAttributedString)
+    func style(text str: NSMutableAttributedString)
+    func style(softBreak str: NSMutableAttributedString)
+    func style(lineBreak str: NSMutableAttributedString)
+    func style(code str: NSMutableAttributedString)
+    func style(htmlInline str: NSMutableAttributedString)
+    func style(customInline str: NSMutableAttributedString)
+    func style(emphasis str: NSMutableAttributedString)
+    func style(strong str: NSMutableAttributedString)
+    func style(link str: NSMutableAttributedString)
+    func style(image str: NSMutableAttributedString)
+}
+
+public class AttributedStringVisitor {
+
+    private let styler: Styler
+    private let options: DownOptions
+
+    init(styler: Styler, options: DownOptions = .default) {
+        self.styler = styler
+        self.options = options
+    }
+}
+
+extension AttributedStringVisitor: Visitor {
+    public typealias Result = NSMutableAttributedString
+
+    public func visit(document node: Document) -> NSMutableAttributedString {
+        let s = visitChildren(of: node).joined
+        styler.style(document: s)
+        return s
+    }
+
+    public func visit(blockQuote node: BlockQuote) -> NSMutableAttributedString {
+        fatalError("unimplemented")
+    }
+
+    public func visit(list node: List) -> NSMutableAttributedString {
+        fatalError("unimplemented")
+    }
+
+    public func visit(item node: Item) -> NSMutableAttributedString {
+        fatalError("unimplemented")
+    }
+
+    public func visit(codeBlock node: CodeBlock) -> NSMutableAttributedString {
+        fatalError("unimplemented")
+    }
+
+    public func visit(htmlBlock node: HtmlBlock) -> NSMutableAttributedString {
+        fatalError("unimplemented")
+    }
+
+    public func visit(customBlock node: CustomBlock) -> NSMutableAttributedString {
+        fatalError("unimplemented")
+    }
+
+    public func visit(paragraph node: Paragraph) -> NSMutableAttributedString {
+        let s = visitChildren(of: node).joined
+        styler.style(paragraph: s)
+        return s
+    }
+
+    public func visit(heading node: Heading) -> NSMutableAttributedString {
+        fatalError("unimplemented")
+    }
+
+    public func visit(thematicBreak node: ThematicBreak) -> NSMutableAttributedString {
+        fatalError("unimplemented")
+    }
+
+    public func visit(text node: Text) -> NSMutableAttributedString {
+        let s = node.literal.attributed
+        styler.style(text: s)
+        return s
+    }
+
+    public func visit(softBreak node: SoftBreak) -> NSMutableAttributedString {
+        let s = (options.contains(.hardBreaks) ? "\n" : " ").attributed
+        styler.style(softBreak: s)
+        return s
+    }
+
+    public func visit(lineBreak node: LineBreak) -> NSMutableAttributedString {
+        let s = "\n".attributed
+        styler.style(lineBreak: s)
+        return s
+    }
+
+    public func visit(code node: Code) -> NSMutableAttributedString {
+        let s = node.literal.attributed
+        styler.style(code: s)
+        return s
+    }
+
+    public func visit(htmlInline node: HtmlInline) -> NSMutableAttributedString {
+        fatalError("unimplemented")
+    }
+
+    public func visit(customInline node: CustomInline) -> NSMutableAttributedString {
+        fatalError("unimplemented")
+    }
+
+    public func visit(emphasis node: Emphasis) -> NSMutableAttributedString {
+        let s = visitChildren(of: node).joined
+        styler.style(emphasis: s)
+        return s
+    }
+
+    public func visit(strong node: Strong) -> NSMutableAttributedString {
+        let s = visitChildren(of: node).joined
+        styler.style(strong: s)
+        return s
+    }
+
+    public func visit(link node: Link) -> NSMutableAttributedString {
+        let s = visitChildren(of: node).joined
+        styler.style(link: s)
+        return s
+    }
+
+    public func visit(image node: Image) -> NSMutableAttributedString {
+        let s = visitChildren(of: node).joined
+        styler.style(image: s)
+        return s
+    }
+}
+
+private extension String {
+    var attributed: NSMutableAttributedString {
+        return NSMutableAttributedString(string: self)
+    }
+}
+
+private extension Sequence where Iterator.Element == NSMutableAttributedString {
+    var joined: NSMutableAttributedString {
+        return reduce(into: NSMutableAttributedString()) { (acc, next) in
+            acc.append(next)
+        }
+    }
+}