Add language configuration for Cabal files

FIxes #128

Author: mchakravarty

Sources/LanguageSupport/CabalConfiguration.swift

@@ -0,0 +1,54 @@
+//
+//  CabalConfiguration.swift
+//  CodeEditorView
+//
+//  Created by Manuel M T Chakravarty on 05/04/2025.
+//
+//  Cabal configuration files: https://www.haskell.org/cabal/
+
+import Foundation
+import RegexBuilder
+
+
+private let cabalReservedIds: [String] = []
+private let cabalReservedOperators     = [":"]
+
+extension LanguageConfiguration {
+
+  /// Language configuration for Cabal configurations
+  ///
+  public static func cabal(_ languageService: LanguageService? = nil) -> LanguageConfiguration {
+    let numberRegex = Regex {
+      optNegation
+      ChoiceOf {
+        Regex{ decimalLit; ZeroOrMore { "."; decimalLit } }
+      }
+    }
+    let identifierRegex = Regex {
+      identifierHeadCharacters
+      ZeroOrMore {
+        CharacterClass(identifierCharacters, .anyOf("'-"))
+      }
+      /\:/
+    }
+    let symbolCharacter = CharacterClass(.anyOf("&<=>|~")),
+        operatorRegex   = Regex {
+          symbolCharacter
+          ZeroOrMore { symbolCharacter }
+        }
+    return LanguageConfiguration(name: "Cabal",
+                                 supportsSquareBrackets: false,
+                                 supportsCurlyBrackets: false,
+                                 indentationSensitiveScoping: true,
+                                 stringRegex: /\"/,
+                                 characterRegex: /'/,
+                                 numberRegex: numberRegex,
+                                 singleLineComment: "--",
+                                 nestedComment: (open: "{-", close: "-}"),
+                                 identifierRegex: identifierRegex,
+                                 operatorRegex: operatorRegex,
+                                 reservedIdentifiers: cabalReservedIds,
+                                 reservedOperators: cabalReservedOperators,
+                                 languageService: languageService)
+  }
+}