lregex: consider aliases of parsers when finding a guest parser

Suggested by @Pierre-Andre in #3288.

Signed-off-by: Masatake YAMATO <[email protected]>

Author: masatake

Units/guest-in-optlib-single-line.d/expected.tags

@@ -28,3 +28,4 @@ g1	input-1.single	/^int g1 (void) { return 0; }$/;"	f	line:6	language:C	typeref:
 g2	input-1.single	/^function g2$/;"	f	line:10	language:Sh
 EOF	input-1.single	/^	cat > foo.rst <<EOF$/;"	h	line:12	language:Sh
 G2 on g2	input-1.single	/^G2 on g2$/;"	H	line:14	language:ReStructuredText
+f	input-2.single	/^f()$/;"	f	line:4	language:Sh

Units/guest-in-optlib-single-line.d/input-2.single

@@ -0,0 +1,8 @@
+ksh is an alias for Sh parser.
+
+BEGIN:ksh
+f()
+{
+	echo x
+}
+END

docs/optlib.rst

@@ -1537,7 +1537,8 @@ For *<PARSER>*, you can specify one of the following items:
 a name of a parser
 
 	If you know the guest parser you want to run before parsing
-	the input file, specify the name of the parser.
+	the input file, specify the name of the parser. Aliases of parsers
+	are also considered when finding a parser for the name.
 
 	An example of running C parser as a guest parser::
 
@@ -1548,7 +1549,8 @@ the group number of a regex pattern started from '``\``' (backslash)
 	If a parser name appears in an input file, write a regex pattern
 	to capture the name.  Specify the group number where the name is
 	stored to the parser.  In such case, use '``\``' as the prefix for
-	the number.
+	the number. Aliases of parsers are also considered when finding
+	a parser for the name.
 
 	Let's see an example. Git Flavor Markdown (GFM) is a language for
 	documentation. It provides a notation for quoting a snippet of

main/lregex.c

@@ -839,7 +839,7 @@ static void pre_ptrn_flag_guest_long (const char* const s, const char* const v,
 	}
 	else
 	{
-		guest->lang.spec.lang = getNamedLanguage (v, (tmp - v));
+		guest->lang.spec.lang = getNamedLanguageOrAlias (v, (tmp - v));
 		if (guest->lang.spec.lang == LANG_IGNORE)
 		{
 			error (WARNING, "no parser found for the guest spec: %s", v);
@@ -1810,7 +1810,7 @@ static bool fillGuestRequest (const char *start,
 			- pmatch [guest_spec->lang.spec.patternGroup].rm_so;
 		if (size > 0)
 		{
-			guest_req->lang = getNamedLanguage (name, size);
+			guest_req->lang = getNamedLanguageOrAlias (name, size);
 			guest_req->lang_set = true;
 		}
 	}