add and document support for tripled-quoted strings

	secret = """foo " bar " baz ! """

doc/antora/modules/reference/pages/type/all_types.adoc

@@ -36,7 +36,7 @@ possible to write values in the format you expect, The server will do
 | ipv4prefix    | IPv4 network with address and prefix length
 | ipv6prefix    | IPv6 network with address and prefix length
 | octets        | raw binary, printed as hex strings
-| string        | printable strings
+| xref:type/string/index.adoc[string]        | printable strings
 | time_delta	| difference between two calendar dates
 | uint8		| 8-bit unsigned integer
 | uint16	| 16-bit unsigned integer

doc/antora/modules/reference/pages/type/index.adoc

@@ -1,7 +1,7 @@
 = Data Types
 
 Unlang supports a number of data types. These data types are used in
-conditional expressions or when assigning a value to an attribute.
+dictionaries, expressions or when assigning a value to an attribute.
 
 == Using Data Types
 

doc/antora/modules/reference/pages/type/string/double.adoc

@@ -8,6 +8,14 @@ xref:xlat/index.adoc[dynamic expansions]. As with
 xref:type/string/single.adoc[single-quoted strings], text within
 double quotes can include spaces.
 
+For normally quoted strings, the quotation character can be placed inside of
+the string by escaping it with a backslash.
+
+For triple quoted strings, the quotation character does not need to be
+escaped.  However, if the string does contain an escaped quotation
+character, the quotation character is unescaped, as with normally
+quoted strings.
+
 The main difference between the single and double quoted strings is
 that the double quoted strings can be dynamically expanded. The syntax
 `${...}` is used for parse-time expansion and `%{...}` is used for
@@ -133,6 +141,7 @@ string is being used.
 `"this has embedded\ncharacters"` +
 `"attribute\tvalue\nusername\t%{User-Name}\nreply-message\t%{reply.Reply-Message}"`
 `"The result of 'SELECT * FROM foo WHERE 1' is: %sql(SELECT * FROM foo WHERE 1)"`
+`"""this string has a "double quoted" string in the middle of it"""`
 
 // Licenced under CC-by-NC 4.0.
 // Copyright (C) 2019 Arran Cudbard-Bell <[email protected]>

doc/antora/modules/reference/pages/type/string/single.adoc

@@ -2,18 +2,27 @@
 
 .Syntax
 `'string'`
+`'''string with 'quote' embedded'''`
 
 A single-quoted string is interpreted without any dynamic string
 expansion. The quotes allow the string to contain spaces, among other
-special characters. The single quote character can be placed in such a
-string by escaping it with a backslash.
+special characters.
+
+For normally quoted strings, the quotation character can be placed inside of
+the string by escaping it with a backslash.
+
+For triple quoted strings, the quotation character does not need to be
+escaped.  However, if the string does contain an escaped quotation
+character, the quotation character is unescaped, as with normally
+quoted strings.
 
 .Examples
 
 `'hello'` +
 `'foo bar`' +
 `'foo\\'bar'` +
 `'this is a long string'`
+`'''This is a string with 'embedded' quotes'''`
 
 // Copyright (C) 2021 Network RADIUS SAS.  Licenced under CC-by-NC 4.0.
 // This documentation was developed by Network RADIUS SAS.

src/lib/server/tmpl_tokenize.c

@@ -5352,6 +5352,7 @@ ssize_t tmpl_preparse(char const **out, size_t *outlen, char const *in, size_t i
 	char quote;
 	char close;
 	int depth;
+	bool triple;
 
 	*type = T_INVALID;
 
@@ -5496,18 +5497,39 @@ ssize_t tmpl_preparse(char const **out, size_t *outlen, char const *in, size_t i
 		 *	more rigorous check.
 		 */
 	skip_string:
+		if ((inlen > 3) && (p[0] == quote) && (p[1] == quote)) {
+			triple = true;
+			p += 2;
+		} else {
+			triple = false;
+		}
 		*out = p;
+
 		while (*p) {
+			if (p >= end) goto unterminated;
+
 			/*
 			 *	End of string.  Tell the caller the
 			 *	length of the data inside of the
 			 *	string, and return the number of
 			 *	characters to skip.
 			 */
 			if (*p == quote) {
-				*outlen = p - (*out);
+				if (!triple) {
+					*outlen = p - (*out);
+					p++;
+					return p - in;
+
+				}
+
+				if (((end - p) >= 3) && (p[1] == quote) && (p[2] == quote)) {
+					*outlen = p - (*out);
+					p += 3;
+					return p - in;
+				}
+
 				p++;
-				return p - in;
+				continue;
 			}
 
 			if (*p == '\\') {
@@ -5523,6 +5545,7 @@ ssize_t tmpl_preparse(char const **out, size_t *outlen, char const *in, size_t i
 		 *	End of input without end of string.
 		 *	Point the error to the start of the string.
 		 */
+		unterminated:
 		p = *out;
 		return_P("Unterminated string");
 

src/lib/util/token.c

@@ -256,6 +256,7 @@ static fr_token_t getthing(char const **ptr, char *buf, int buflen, bool tok,
 	char			*s;
 	char const		*p;
 	char			quote;
+	bool			triple = false;
 	unsigned int		x;
 	size_t			i;
 	fr_token_t 		token;
@@ -315,6 +316,14 @@ static fr_token_t getthing(char const **ptr, char *buf, int buflen, bool tok,
 
 	if (token != T_BARE_WORD) {
 		quote = *p;
+
+		/*
+		 *	Triple-quoted strings are copied over verbatim, without escapes.
+		 */
+		if ((buflen >= 3) && (p[1] == quote) && (p[2] == quote)) {
+			p += 3;
+		}
+
 		p++;
 	}
 	s = buf;
@@ -350,9 +359,21 @@ static fr_token_t getthing(char const **ptr, char *buf, int buflen, bool tok,
 		 *	Un-escaped quote character.  We're done.
 		 */
 		if (*p == quote) {
-			p++;
-			*s++ = 0;
-			goto done;
+			if (!triple) {
+				p++;
+				*s++ = 0;
+				goto done;
+
+			}
+
+			if ((buflen >= 3) && (p[1] == quote) && (p[2] == quote)) {
+				p += 3;
+				*s++ = 0;
+				goto done;
+			}
+
+			*s++ = *p++;
+			continue;
 		}
 
 		/*