Merge pull request #108 from hamishknight/all-the-patter

Author: hamishknight

Sources/_MatchingEngine/Regex/AST/Atom.swift

@@ -382,34 +382,43 @@ extension AST.Atom.CharacterProperty {
   }
 }
 
+extension AST.Atom {
+  public struct Reference: Hashable {
+    @frozen
+    public enum Kind: Hashable {
+      // \n \gn \g{n} \g<n> \g'n' (?n) (?(n)...
+      // Oniguruma: \k<n>, \k'n'
+      case absolute(Int)
+
+      // \g{-n} \g<+n> \g'+n' \g<-n> \g'-n' (?+n) (?-n)
+      // (?(+n)... (?(-n)...
+      // Oniguruma: \k<-n> \k<+n> \k'-n' \k'+n'
+      case relative(Int)
+
+      // \k<name> \k'name' \g{name} \k{name} (?P=name)
+      // \g<name> \g'name' (?&name) (?P>name)
+      // (?(<name>)... (?('name')... (?(name)...
+      case named(String)
+
+      /// (?R), (?(R)..., which are equivalent to (?0), (?(0)...
+      static var recurseWholePattern: Kind { .absolute(0) }
+    }
+    public var kind: Kind
 
-// TODO: I haven't thought through this a bunch; this seems like
-// a sensible type to have and break down this way. But it could
-// easily get folded in with the kind of reference
-@frozen
-public enum Reference: Hashable {
-  // \n \gn \g{n} \g<n> \g'n' (?n) (?(n)...
-  // Oniguruma: \k<n>, \k'n'
-  case absolute(Int)
-
-  // \g{-n} \g<+n> \g'+n' \g<-n> \g'-n' (?+n) (?-n)
-  // (?(+n)... (?(-n)...
-  // Oniguruma: \k<-n> \k<+n> \k'-n' \k'+n'
-  case relative(Int)
-
-  // \k<name> \k'name' \g{name} \k{name} (?P=name)
-  // \g<name> \g'name' (?&name) (?P>name)
-  // (?(<name>)... (?('name')... (?(name)...
-  case named(String)
-
-  // TODO: I'm not sure the below goes here
-  //
-  // ?(R) (?(R)...
-  case recurseWholePattern
-}
-
+    /// The location of the inner numeric or textual reference, e.g the location
+    /// of '-2' in '\g{-2}'.
+    public var innerLoc: SourceLocation
 
+    public init(_ kind: Kind, innerLoc: SourceLocation) {
+      self.kind = kind
+      self.innerLoc = innerLoc
+    }
 
+    /// Whether this is a reference that recurses the whole pattern, rather than
+    /// a group.
+    public var recursesWholePattern: Bool { kind == .recurseWholePattern }
+  }
+}
 
 extension AST.Atom {
   /// Anchors and other built-in zero-width assertions

Sources/_MatchingEngine/Regex/Parse/Diagnostics.swift

@@ -30,6 +30,13 @@ enum ParseError: Error, Hashable {
 
   case expectedASCII(Character)
 
+  case expectedNonEmptyContents
+
+  case unknownGroupKind(String)
+
+  case invalidMatchingOption(Character)
+  case cannotRemoveMatchingOptionsAfterCaret
+
   case expectedCustomCharacterClassMembers
   case invalidCharacterClassRangeOperand
 
@@ -61,6 +68,14 @@ extension ParseError: CustomStringConvertible {
       return "unexpected end of input"
     case let .misc(s):
       return s
+    case .expectedNonEmptyContents:
+      return "expected non-empty contents"
+    case let .unknownGroupKind(str):
+      return "unknown group kind '(\(str)'"
+    case let .invalidMatchingOption(c):
+      return "invalid matching option '\(c)'"
+    case .cannotRemoveMatchingOptionsAfterCaret:
+      return "cannot remove matching options with '^' specifier"
     case let .expectedASCII(c):
       return "expected ASCII for '\(c)'"
     case .expectedCustomCharacterClassMembers: