Exposed the throwing parser function as public and updated error descriptions

Author: htinlinn

Marker/Classes/Marker.swift

@@ -8,17 +8,51 @@
 
 import Foundation
 
-/// Returns formatted Markdown text as an attributed string.
+/// Parses Markdown text and eturns formatted text as an attributed string with custom markup attributes applied.
+/// If the parsing failed, specified Markdown tags are ignored. Yet, the rest of the style information is still applied.
 ///
 /// - Parameters:
-///   - markdownText: String with Markdown tags.
+///   - text: Text.
 ///   - textStyle: Text style object containing style information.
-/// - Returns: Formatted Markdown text.
+///   - markups: Markup information.
+/// - Returns: Formatted text.
 public func attributedMarkdownString(from markdownText: String,
                                      using textStyle: TextStyle) -> NSAttributedString {
-    guard let (parsedString, elements) = try? MarkdownParser.parse(markdownText) else {
+    do {
+        return try parsedMarkdownString(from: markdownText, using: textStyle)
+    } catch {
         return NSAttributedString(string: markdownText, textStyle: textStyle)
     }
+}
+
+/// Parses custom mark up information and returns formatted text as an attributed string with custom markup attributes applied.
+/// If the parsing failed, custom markup attributes are ignored. Yet, style information from `textStyle` parameter is still applied.
+///
+/// - Parameters:
+///   - text: Text.
+///   - textStyle: Text style object containing style information.
+///   - markups: Markup information.
+/// - Returns: Formatted text.
+public func attributedMarkupString(from text: String,
+                                   using textStyle: TextStyle,
+                                   customMarkup markups: Markup) -> NSAttributedString {
+    do {
+        return try parsedMarkupString(from: text, using: textStyle, customMarkup: markups)
+    } catch {
+        return NSAttributedString(string: text, textStyle: textStyle)
+    }
+}
+
+/// Returns formatted Markdown text as an attributed string.
+///
+/// - Parameters:
+///   - markdownText: String with Markdown tags.
+///   - textStyle: Text style object containing style information.
+/// - Returns: Formatted Markdown text.
+/// - Throws: Parser error.
+public func parsedMarkdownString(from markdownText: String,
+                                 using textStyle: TextStyle) throws -> NSAttributedString {
+    let (parsedString, elements) = try MarkdownParser.parse(markdownText)
 
     let attributedString = NSMutableAttributedString(string: textStyle.textTransform.applied(to: parsedString))
     attributedString.addAttributes(textStyle.attributes,
@@ -62,14 +96,15 @@ public func attributedMarkdownString(from markdownText: String,
 ///   - textStyle: Text style object containing style information.
 ///   - markups: Markup information.
 /// - Returns: Formatted text.
-public func attributedMarkupString(from text: String,
-                                   using textStyle: TextStyle,
-                                   customMarkup markups: Markup) -> NSAttributedString {
-    guard
-        markups.count > 0,
-        let (parsedString, elements) = try? ElementParser.parse(text, for: markups.map { Symbol(character: $0.0) }) else {
-            return NSAttributedString(string: text, textStyle: textStyle)
+/// - Throws: Parser error.
+public func parsedMarkupString(from text: String,
+                               using textStyle: TextStyle,
+                               customMarkup markups: Markup) throws -> NSAttributedString {
+    guard markups.count > 0 else {
+        return NSAttributedString(string: text, textStyle: textStyle)
     }
+
+    let (parsedString, elements) = try ElementParser.parse(text, for: markups.map { Symbol(character: $0.0) })
 
     let attributedString = NSMutableAttributedString(string: textStyle.textTransform.applied(to: parsedString))
     attributedString.addAttributes(textStyle.attributes,

Marker/Classes/Parser/ElementParser.swift

@@ -15,9 +15,20 @@ internal struct ElementParser {
     ///
     /// - tagMismatch: Opening tag doesn't match closing tag.
     /// - unclosedTags: A tag was left unclosed.
-    enum ParserError: Error {
+    enum ParserError: LocalizedError {
+
         case tagMismatch
         case unclosedTags
+
+        var errorDescription: String? {
+            switch self {
+            case .tagMismatch:
+                return "Opening tag doesn't match closing tag."
+            case .unclosedTags:
+                return "A tag was left unclosed."
+            }
+        }
+
     }
 
     // MARK: - Static functions

Marker/Classes/Parser/MarkdownParser.swift

@@ -11,10 +11,13 @@ internal struct MarkdownParser {
 
     /// Parser error.
     ///
-    /// - tagMismatch: Opening tag doesn't match closing tag.
-    /// - unclosedTags: A tag was left unclosed.
-    enum ParserError: Error {
+    /// - invalidTagSymbol: Tag symbol is not a Markdown symbol.
+    enum ParserError: LocalizedError {
         case invalidTagSymbol
+
+        var errorDescription: String? {
+            return "Invalid Markdown tag."
+        }
     }
 
     // MARK: - Private properties