regexp backreferences: Implement fallback to octal numbers, and ECMAScript semantics.

* syntax.cs (BackslashNumber.ResolveReference): Implement fallback
to octal numbers, and ECMAScript semantics.
* parser.cs (ResolveReferences): Use it.
* RegexMatchTests.cs (RegexTrial0054..60): New.

svn path=/trunk/mcs/; revision=139657

Author: harinath

mcs/class/System/System.Text.RegularExpressions/ChangeLog

@@ -1,3 +1,9 @@
+2009-08-10  Raja R Harinath  <[email protected]>
+
+	* syntax.cs (BackslashNumber.ResolveReference): Implement fallback
+	to octal numbers, and ECMAScript semantics.
+	* parser.cs (ResolveReferences): Use it.
+
 2009-08-10  Raja R Harinath  <[email protected]>
 
 	* syntax.cs (BackslashNumber): New class.

mcs/class/System/System.Text.RegularExpressions/parser.cs

@@ -1102,6 +1102,9 @@ private void ResolveReferences () {
 				if (!dict.Contains (name)) {
 					if (expr is CaptureAssertion && !Char.IsDigit (name [0]))
 						continue;
+					BackslashNumber bn = expr as BackslashNumber;
+					if (bn != null && bn.ResolveReference (name, dict))
+						continue;
 					throw NewParseException ("Reference to undefined group " +
 						(Char.IsDigit (name[0]) ? "number " : "name ") +
 						name);

mcs/class/System/System.Text.RegularExpressions/syntax.cs

@@ -702,7 +702,8 @@ public bool IgnoreCase {
 			set { ignore = value; }
 		}
 
-		public override void Compile (ICompiler cmp, bool reverse) {
+		public static void CompileLiteral (string str, ICompiler cmp, bool ignore, bool reverse)
+		{
 			if (str.Length == 0)
 				return;
 
@@ -712,6 +713,11 @@ public override void Compile (ICompiler cmp, bool reverse) {
 				cmp.EmitString (str, ignore, reverse);
 		}
 
+		public override void Compile (ICompiler cmp, bool reverse)
+		{
+			CompileLiteral (str, cmp, ignore, reverse);
+		}
+
 		public override void GetWidth (out int min, out int max) {
 			min = max = str.Length;
 		}
@@ -806,6 +812,49 @@ public BackslashNumber (bool ignore, bool ecma)
 		{
 			this.ecma = ecma;
 		}
+
+		// Precondition: groups [num_str] == null
+		public bool ResolveReference (string num_str, Hashtable groups)
+		{
+			if (ecma) {
+				int i;
+				for (i = 1; i < num_str.Length; ++i) {
+					string name = num_str.Substring (0, i);
+					CapturingGroup group = (CapturingGroup) groups [name];
+					if (group == null)
+						break;
+					CapturingGroup = group;
+				}
+				if (i > 1) {
+					literal = num_str.Substring (i - 1);
+					return true;
+				}
+			} else {
+				if (num_str.Length == 1)
+					return false;
+			}
+
+			int ptr = 0;
+			int as_octal = Parser.ParseOctal (num_str, ref ptr);
+			// Since ParseOctal reads at most 3 digits, as_octal <= octal 0777
+			if (as_octal == -1)
+				return false;
+			if (as_octal > 0xff && ecma) {
+				as_octal /= 8;
+				--ptr;
+			}
+			as_octal &= 0xff;
+			literal = ((char) as_octal) + num_str.Substring (ptr);
+			return true;
+		}
+
+		public override void Compile (ICompiler cmp, bool reverse)
+		{
+			if (CapturingGroup != null)
+				base.Compile (cmp, reverse);
+			if (literal != null)
+				Literal.CompileLiteral (literal, cmp, IgnoreCase, reverse);
+		}
 	}
 
 	class CharacterClass : Expression {

mcs/class/System/Test/System.Text.RegularExpressions/ChangeLog

@@ -1,3 +1,7 @@
+2009-08-10  Raja R Harinath  <[email protected]>
+
+	* RegexMatchTests.cs (RegexTrial0054..60): New.
+
 2009-08-10  Raja R Harinath  <[email protected]>
 
 	* RegexMatchTests.cs (RegexTrial0053): New.

mcs/class/System/Test/System.Text.RegularExpressions/RegexMatchTests.cs

@@ -150,6 +150,13 @@ public class RegexMatchTests
 			new RegexTrial (@"(?>a*).", RegexOptions.ExplicitCapture, "aaaa", "Fail."),//52
 
 			new RegexTrial (@"(?<ab>ab)c\1", RegexOptions.None, "abcabc", "Pass. Group[0]=(0,5) Group[1]=(0,2)"),//53
+			new RegexTrial (@"\1", RegexOptions.ECMAScript, "-", "Fail."),//54
+			new RegexTrial (@"\2", RegexOptions.ECMAScript, "-", "Fail."),//55
+			new RegexTrial (@"(a)|\2", RegexOptions.ECMAScript, "-", "Fail."),//56
+			new RegexTrial (@"\4400", RegexOptions.None, "asdf 012", "Pass. Group[0]=(4,2)"),//57
+			new RegexTrial (@"\4400", RegexOptions.ECMAScript, "asdf 012", "Fail."),//58
+			new RegexTrial (@"\4400", RegexOptions.None, "asdf$0012", "Fail."),//59
+			new RegexTrial (@"\4400", RegexOptions.ECMAScript, "asdf$0012", "Pass. Group[0]=(4,3)"),//60
 		};
 
 		[Test]
@@ -322,5 +329,12 @@ public void RegexJvmTrial0018 ()
 		[Test]	public void RegexJvmTrial0052 () { trials [52].Execute (); }
 
 		[Test]	public void RegexTrial0053 () { trials [53].Execute (); }
+		[Test]	public void RegexTrial0054 () { trials [54].Execute (); }
+		[Test]	public void RegexTrial0055 () { trials [55].Execute (); }
+		[Test]	public void RegexTrial0056 () { trials [56].Execute (); }
+		[Test]	public void RegexTrial0057 () { trials [57].Execute (); }
+		[Test]	public void RegexTrial0058 () { trials [58].Execute (); }
+		[Test]	public void RegexTrial0059 () { trials [59].Execute (); }
+		[Test]	public void RegexTrial0060 () { trials [60].Execute (); }
 	}
 }