Feature/named capturing groups

Notepad/Storage.swift

@@ -126,7 +126,18 @@ public class Storage: NSTextStorage {
         for (style) in theme.styles {
             style.regex.enumerateMatches(in: backingString, options: .withoutAnchoringBounds, range: range, using: { (match, flags, stop) in
                 guard let match = match else { return }
+
                 backingStore.addAttributes(style.attributes, range: match.range(at: 0))
+                if #available(iOS 11.0, *) {
+                    if let groups = style.groups {
+                        for group in groups {
+                            if let groupStyle = theme.style(withName: group) {
+                                let range = match.range(withName: group)
+                                backingStore.addAttributes(groupStyle.attributes, range: range)
+                            }
+                        }
+                    }
+                }
             })
         }
     }

Notepad/Style.swift

@@ -9,17 +9,23 @@
 import Foundation
 
 public struct Style {
+    public var name: String?
     var regex: NSRegularExpression!
     public var attributes: [NSAttributedString.Key: Any] = [:]
+    var groups: [String]?
 
-    public init(element: Element, attributes: [NSAttributedString.Key: Any]) {
+    public init(element: Element, attributes: [NSAttributedString.Key: Any], groups: [String]? = nil, name: String? = nil) {
+        self.name = name
         self.regex = element.toRegex()
         self.attributes = attributes
+        self.groups = groups
     }
 
-    public init(regex: NSRegularExpression, attributes: [NSAttributedString.Key: Any]) {
+    public init(regex: NSRegularExpression, attributes: [NSAttributedString.Key: Any], groups: [String]? = nil, name: String? = nil) {
+        self.name = name
         self.regex = regex
         self.attributes = attributes
+        self.groups = groups
     }
 
     public init() {

Notepad/Theme.swift

@@ -41,6 +41,9 @@ public struct Theme {
     /// All of the other styles for the Notepad editor.
     public var styles: [Style] = []
 
+    public func style(withName name: String) -> Style? {
+        styles.first(where: { $0.name == name })
+    }
 
     /// Build a theme from a JSON theme file.
     ///
@@ -120,12 +123,13 @@ public struct Theme {
             allStyles.removeValue(forKey: "body")
             for (element, attributes) in allStyles {
                 if let parsedStyles = parse(attributes as! [String : AnyObject]) {
+                    let groups = attributes["groups"] as? [String]
+
                     if let regexString = attributes["regex"] as? String {
                         let regex = regexString.toRegex()
-                        styles.append(Style(regex: regex, attributes: parsedStyles))
-                    }
-                    else {
-                        styles.append(Style(element: Element.unknown.from(string: element), attributes: parsedStyles))
+                        styles.append(Style(regex: regex, attributes: parsedStyles, groups: groups, name: element))
+                    } else {
+                        styles.append(Style(element: Element.unknown.from(string: element), attributes: parsedStyles, groups: groups, name: element))
                     }
                 }
             }

Notepad/themes/one-dark-custom.json

@@ -25,10 +25,15 @@
             "size": 25
         },
         "h3": {
+            "regex": "^((?<hash>\\#{3})(.*))$",
             "font": "Courier-Bold",
-            "color": "#D36770",
+            "groups": ["hash"],
+            "color": "#FFFFFF",
             "size": 22
         },
+        "hash": {
+            "color": "#D36770"
+        },
         "body": {
             "font": "Courier",
             "size": 17,