Add escape sequences to char literals

Author: gracjan

haskell-lexeme.el

@@ -107,13 +107,16 @@ Note that (match-string 1) returns the unqualified part.")
 Note that negative sign char is not part of a number.")
 
 (defconst haskell-lexeme-char-literal-inside
-  (rx (| (regexp "[^\n'\\]")
+  (rx (| (not (any "\n'\\"))
          (: "\\"
             (| "a" "b" "f" "n" "r" "t" "v" "\\" "\"" "'"
                "NUL" "SOH" "STX" "ETX" "EOT" "ENQ" "ACK"
                "BEL" "BS" "HT" "LF" "VT" "FF" "CR" "SO" "SI" "DLE"
                "DC1" "DC2" "DC3" "DC4" "NAK" "SYN" "ETB" "CAN"
                "EM" "SUB" "ESC" "FS" "GS" "RS" "US" "SP" "DEL"
+               (regexp "[0-9]+")
+               (: "x" (regexp "[0-9a-fA-F]+"))
+               (: "o" (regexp "[0-7]+"))
                (: "^" (regexp "[]A-Z@^_\\[]"))))))
   "Regexp matching an inside of a character literal.")
 

tests/haskell-font-lock-tests.el

@@ -36,6 +36,11 @@
      ("_f" "w" haskell-symbol-face)
      ("_'''" "w" haskell-symbol-face))))
 
+(ert-deftest haskell-syntactic-test-character-literal-escapes ()
+  (check-properties
+   '("'\\000' '\\x01'")
+   '(("'\\000'" t font-lock-string-face)
+     ("'\\x01'" t font-lock-string-face))))
 
 (ert-deftest haskell-syntactic-test-7 ()
   "Take quotes and double quotes under control."