Allow escape characters \a \b \f \v (#1025)

build/quote.go

@@ -27,19 +27,27 @@ import (
 
 // unesc maps single-letter chars following \ to their actual values.
 var unesc = [256]byte{
+	'a':  '\a',
+	'b':  '\b',
+	'f':  '\f',
 	'n':  '\n',
 	'r':  '\r',
 	't':  '\t',
+	'v':  '\v',
 	'\\': '\\',
 	'\'': '\'',
 	'"':  '"',
 }
 
 // esc maps escape-worthy bytes to the char that should follow \.
 var esc = [256]byte{
+	'\a': 'a',
+	'\b': 'b',
+	'\f': 'f',
 	'\n': 'n',
 	'\r': 'r',
 	'\t': 't',
+	'\v': 'v',
 	'\\': '\\',
 	'\'': '\'',
 	'"':  '"',
@@ -49,9 +57,13 @@ var esc = [256]byte{
 // in a string literal
 var escapable = [256]bool{
 	'\n': true,
+	'a':  true,
+	'b':  true,
+	'f':  true,
 	'n':  true,
 	'r':  true,
 	't':  true,
+	'v':  true,
 	'x':  true,
 	'\'': true,
 	'\\': true,
@@ -138,7 +150,7 @@ func Unquote(quoted string) (s string, triple bool, err error) {
 			// Ignore the escape and the line break.
 			quoted = quoted[2:]
 
-		case 'n', 'r', 't', '\\', '\'', '"':
+		case 'a', 'b', 'f', 'n', 'r', 't', 'v', '\\', '\'', '"':
 			// One-char escape
 			buf.WriteByte(unesc[quoted[1]])
 			quoted = quoted[2:]

build/testdata/060.golden

@@ -41,13 +41,17 @@ strings = [
     r"\a\b\c\d\e\f\g\h\i\j\k\l\m\n\o\p\q\r\s\t\u\v\w\x43\y\z\0\1\2\3\4\5\6\7\8\9\\n",
 
     # contain incorrect escape sequences
-    "\\a'",
-    "\\a\"",
-    """\\a'""",
-    """\\a\"""",
-    "\\a\\b\\c\\d\\e\\f\\g\\h\\i\\j\\k\\l\\m\n\\o\\p\\q\r\\s\t\\u\\v\\wC\\y\\z\000\001\002\003\004\005\006\007\\8\\9",
+    "\\c'",
+    "\\c\"",
+    """\\c'""",
+    """\\c\"""",
+    "\a\b\\c\\d\\e\f\\g\\h\\i\\j\\k\\l\\m\n\\o\\p\\q\r\\s\t\\u\v\\wC\\y\\z\000\001\002\003\004\005\006\a\\8\\9",
 
     # correct escape sequences
+    """\a\b\f\n\r\t\v\007\010\
+  """,
+    """\a\b\f
+\r\t\v\a\b  """,
     """ aa\\bb\n \
   """,
     "\000\111\222",

build/testdata/060.in

@@ -41,13 +41,17 @@ strings = [
   r"\a\b\c\d\e\f\g\h\i\j\k\l\m\n\o\p\q\r\s\t\u\v\w\x43\y\z\0\1\2\3\4\5\6\7\8\9\\n",
 
   # contain incorrect escape sequences
-  "\a'",
-  '\a"',
-  """\a'""",
-  '''\a"''',
+  "\c'",
+  '\c"',
+  """\c'""",
+  '''\c"''',
   "\a\b\c\d\e\f\g\h\i\j\k\l\m\n\o\p\q\r\s\t\u\v\w\x43\y\z\0\1\2\3\4\5\6\7\8\9",
 
   # correct escape sequences
+  """\a\b\f\n\r\t\v\007\010\
+  """,
+  '''\a\b\f\n\r\t\v\007\010\
+  ''',
   """ aa\\bb\n \
   """,
   "\000\111\222",