# HG changeset patch
# User Adam Chlipala <adamc@hcoop.net>
# Date 1262109326 18000
# Node ID c023bc6ab914ea8f9f63be22d465f0b39cc841f8
# Parent  80d048a8efe58b29b26b5875f49964d644449c43
Octal and hexidecimal string escapes

diff -r 80d048a8efe5 -r c023bc6ab914 src/urweb.lex
--- a/src/urweb.lex	Tue Dec 29 10:28:02 2009 -0500
+++ b/src/urweb.lex	Tue Dec 29 12:55:26 2009 -0500
@@ -168,6 +168,8 @@
 intconst = [0-9]+;
 realconst = [0-9]+\.[0-9]*;
 notags = [^<{\n]+;
+oint = [0-9][0-9][0-9];
+xint = x[0-9a-fA-F][0-9a-fA-F];
 
 %%
 
@@ -199,6 +201,16 @@
 <STRING,CHAR> "\\t"   => (str := #"\t" :: !str; continue());
 <STRING,CHAR> "\n"    => (newline yypos;
 			  str := #"\n" :: !str; continue());
+<STRING,CHAR> "\\" {oint} => (case StringCvt.scanString (Int.scan StringCvt.OCT)
+                                                        (String.extract (yytext, 1, NONE)) of
+                                  NONE => ErrorMsg.errorAt' (pos yypos, pos yypos) "Illegal string escape"
+                                | SOME n => str := chr n :: !str;
+                              continue());
+<STRING,CHAR> "\\" {xint} => (case StringCvt.scanString (Int.scan StringCvt.HEX)
+                                                        (String.extract (yytext, 2, NONE)) of
+                                  NONE => ErrorMsg.errorAt' (pos yypos, pos yypos) "Illegal string escape"
+                                | SOME n => str := chr n :: !str;
+                              continue());
 
 <INITIAL> "#\""       => (YYBEGIN CHAR; strEnder := #"\""; strStart := pos yypos; str := []; continue());