Change the compiler function structure and add tests.

Author: Luma

autoload/vimlparser.vim

@@ -4977,9 +4977,9 @@ function! s:Compiler.compile_function(node) abort
   if empty(rlist)
     call self.out('(function (%s)', left)
   elseif empty(default_args)
-    call self.out('(function (%s) (%s)', left, join(rlist, ' '))
+    call self.out('(function (%s (%s))', left, join(rlist, ' '))
   else
-    call self.out('(function (%s) (%s) (%s)', left, join(rlist, ' '), join(default_args, ' '))
+    call self.out('(function (%s (%s) (%s))', left, join(rlist, ' '), join(default_args, ' '))
   endif
   call self.incindent('  ')
   call self.compile_body(a:node.body)

js/vimlparser.js

@@ -4482,10 +4482,10 @@ Compiler.prototype.compile_function = function(node) {
         this.out("(function (%s)", left);
     }
     else if (viml_empty(default_args)) {
-        this.out("(function (%s) (%s)", left, viml_join(rlist, " "));
+        this.out("(function (%s (%s))", left, viml_join(rlist, " "));
     }
     else {
-        this.out("(function (%s) (%s) (%s)", left, viml_join(rlist, " "), viml_join(default_args, " "));
+        this.out("(function (%s (%s) (%s))", left, viml_join(rlist, " "), viml_join(default_args, " "));
     }
     this.incindent("  ");
     this.compile_body(node.body);

py/vimlparser.py

@@ -3587,9 +3587,9 @@ def compile_function(self, node):
         if viml_empty(rlist):
             self.out("(function (%s)", left)
         elif viml_empty(default_args):
-            self.out("(function (%s) (%s)", left, viml_join(rlist, " "))
+            self.out("(function (%s (%s))", left, viml_join(rlist, " "))
         else:
-            self.out("(function (%s) (%s) (%s)", left, viml_join(rlist, " "), viml_join(default_args, " "))
+            self.out("(function (%s (%s) (%s))", left, viml_join(rlist, " "), viml_join(default_args, " "))
         self.incindent("  ")
         self.compile_body(node.body)
         self.out(")")

test/test1.ok

@@ -1,7 +1,7 @@
 ; test1
-(function (s:foo) (a b . ...)
+(function (s:foo (a b . ...))
   (return 0))
-(function (s:bar) (a b . ...) (1 2)
+(function (s:bar (a b . ...) (1 2))
   (return 0))
 (if 1
   (echo "if 1")

test/test_funcarg.ok

@@ -0,0 +1,2 @@
+(function (X (foo) ((+ 1 2)))
+  (return a:foo))

test/test_funcarg.vim

@@ -0,0 +1,3 @@
+function X(foo=1+2)
+  return a:foo
+endfunction

test/test_xxx_funcarg_last_comma.ok

@@ -1,2 +1,2 @@
-(function (F) (a))
-(function (G) (a))
+(function (F (a)))
+(function (G (a)))