patch 8.1.1310: named function arguments are never optional
Problem: Named function arguments are never optional.
Solution: Support optional function arguments with a default value. (Andy
Massimino, closes #3952)
diff --git a/src/testdir/test_user_func.vim b/src/testdir/test_user_func.vim
index e7a3701..666c06c 100644
--- a/src/testdir/test_user_func.vim
+++ b/src/testdir/test_user_func.vim
@@ -94,3 +94,53 @@
unlet g:retval g:counter
enew!
endfunc
+
+func Log(val, base = 10)
+ return log(a:val) / log(a:base)
+endfunc
+
+func Args(mandatory, optional = v:null, ...)
+ return deepcopy(a:)
+endfunc
+
+func Args2(a = 1, b = 2, c = 3)
+ return deepcopy(a:)
+endfunc
+
+func MakeBadFunc()
+ func s:fcn(a, b=1, c)
+ endfunc
+endfunc
+
+func Test_default_arg()
+ call assert_equal(1.0, Log(10))
+ call assert_equal(log(10), Log(10, exp(1)))
+ call assert_fails("call Log(1,2,3)", 'E118')
+
+ let res = Args(1)
+ call assert_equal(res.mandatory, 1)
+ call assert_equal(res.optional, v:null)
+ call assert_equal(res['0'], 0)
+
+ let res = Args(1,2)
+ call assert_equal(res.mandatory, 1)
+ call assert_equal(res.optional, 2)
+ call assert_equal(res['0'], 0)
+
+ let res = Args(1,2,3)
+ call assert_equal(res.mandatory, 1)
+ call assert_equal(res.optional, 2)
+ call assert_equal(res['0'], 1)
+
+ call assert_fails("call MakeBadFunc()", 'E989')
+ call assert_fails("fu F(a=1 ,) | endf", 'E475')
+
+ let d = Args2(7, v:none, 9)
+ call assert_equal([7, 2, 9], [d.a, d.b, d.c])
+
+ call assert_equal("\n"
+ \ .. " function Args2(a = 1, b = 2, c = 3)\n"
+ \ .. "1 return deepcopy(a:)\n"
+ \ .. " endfunction",
+ \ execute('func Args2'))
+endfunc