[vala/wip/ricotz/lsp: 5/13] langserver: improve signature help

[Rico Tzschichholz <ricotz src gnome org>]

commit cf7d606f62252e265f5c8f2cd5de955a0ee45222
Author: Princeton Ferro <princetonferro gmail com>
Date:   Thu Jan 9 09:48:07 2020 -0500

    langserver: improve signature help

 vala/valamethodcall.vala |  5 +++++
 vala/valaparser.vala     | 11 ++++++++---
 2 files changed, 13 insertions(+), 3 deletions(-)
---
diff --git a/vala/valamethodcall.vala b/vala/valamethodcall.vala
index 95cc41a42..f8b1578b2 100644
--- a/vala/valamethodcall.vala
+++ b/vala/valamethodcall.vala
@@ -53,6 +53,11 @@ public class Vala.MethodCall : Expression {
         */
        public int initial_argument_count { get; set; }
 
+       /**
+        * For language servers, whether there is an extra comma at the end of the argument list.
+        */
+       public bool extra_comma { get; set; }
+
        private Expression _call;
 
        private List<Expression> argument_list = new ArrayList<Expression> ();
diff --git a/vala/valaparser.vala b/vala/valaparser.vala
index 79aa98713..a0704b047 100644
--- a/vala/valaparser.vala
+++ b/vala/valaparser.vala
@@ -563,14 +563,16 @@ public class Vala.Parser : CodeVisitor {
                return type;
        }
 
-       List<Expression> parse_argument_list () throws ParseError {
+       List<Expression> parse_argument_list (out bool extra_comma) throws ParseError {
                var list = new ArrayList<Expression> ();
+               extra_comma = false;
                if (current () != TokenType.CLOSE_PARENS) {
                        do {
                                try {
                                        list.add (parse_argument ());
                                } catch (ParseError e) {
                                        if (context.keep_going) {
+                                               extra_comma = true;
                                                report_parse_error (e);
                                                // exit this loop, since language server uses
                                                // number of correctly-supplied arguments from
@@ -803,7 +805,8 @@ public class Vala.Parser : CodeVisitor {
 
        Expression parse_method_call (SourceLocation begin, Expression inner) throws ParseError {
                expect (TokenType.OPEN_PARENS);
-               var arg_list = parse_argument_list ();
+               bool extra_comma;
+               var arg_list = parse_argument_list (out extra_comma);
                if (context.keep_going) {
                        if (!accept (TokenType.CLOSE_PARENS)) {
                                report_parse_error (new ParseError.SYNTAX ("expected %s".printf 
(TokenType.CLOSE_PARENS.to_string ())), false);
@@ -835,6 +838,7 @@ public class Vala.Parser : CodeVisitor {
                                expr.add_argument (arg);
                        }
                        expr.initial_argument_count = arg_list.size;
+                       expr.extra_comma = extra_comma;
                        return expr;
                }
        }
@@ -923,7 +927,8 @@ public class Vala.Parser : CodeVisitor {
 
        Expression parse_object_creation_expression (SourceLocation begin, MemberAccess member) throws 
ParseError {
                member.creation_member = true;
-               var arg_list = parse_argument_list ();
+               bool extra_comma;
+               var arg_list = parse_argument_list (out extra_comma);
                expect (TokenType.CLOSE_PARENS);
                var src = get_src (begin);