vim-patch:8.1.1911: more functions can be used as methods

Problem:    More functions can be used as methods.
Solution:   Make a few more functions usable as a method.
64b4d73524

Note that the old-style version of Test_byteidx() was already translated
to a Lua test in 069_multibyte_formatting_spec.lua. Keep both versions,
using Test_byteidx() to mainly test the method call syntax for byteidx()
and byteidxcomp().

runtime/doc/eval.txt

@@ -2954,6 +2954,9 @@ byte2line({byte})					*byte2line()*
 		one.
 		Also see |line2byte()|, |go| and |:goto|.
 
+		Can also be used as a |method|: >
+			GetOffset()->byte2line()
+
 byteidx({expr}, {nr})					*byteidx()*
 		Return byte index of the {nr}'th character in the string
 		{expr}.  Use zero for the first character, it then returns
@@ -2976,6 +2979,9 @@ byteidx({expr}, {nr})					*byteidx()*
 		If there are exactly {nr} characters the length of the string
 		in bytes is returned.
 
+		Can also be used as a |method|: >
+			GetName()->byteidx(idx)
+
 byteidxcomp({expr}, {nr})					*byteidxcomp()*
 		Like byteidx(), except that a composing character is counted
 		as a separate character.  Example: >
@@ -2989,6 +2995,9 @@ byteidxcomp({expr}, {nr})					*byteidxcomp()*
 		Only works differently from byteidx() when 'encoding' is set to
 		a Unicode encoding.
 
+		Can also be used as a |method|: >
+			GetName()->byteidxcomp(idx)
+
 call({func}, {arglist} [, {dict}])			*call()* *E699*
 		Call function {func} with the items in |List| {arglist} as
 		arguments.
@@ -2998,6 +3007,9 @@ call({func}, {arglist} [, {dict}])			*call()* *E699*
 		{dict} is for functions with the "dict" attribute.  It will be
 		used to set the local variable "self". |Dictionary-function|
 
+		Can also be used as a |method|: >
+			GetFunc()->call([arg, arg], dict)
+
 ceil({expr})							*ceil()*
 		Return the smallest integral value greater than or equal to
 		{expr} as a |Float| (round up).

src/nvim/eval.lua

@@ -62,10 +62,10 @@ return {
     bufnr={args={0, 2}, base=1},
     bufwinid={args=1, base=1},
     bufwinnr={args=1, base=1},
-    byte2line={args=1},
+    byte2line={args=1, base=1},
-    byteidx={args=2},
+    byteidx={args=2, base=1},
-    byteidxcomp={args=2},
+    byteidxcomp={args=2, base=1},
-    call={args={2, 3}},
+    call={args={2, 3}, base=1},
     ceil={args=1, base=1, func="float_op_wrapper", data="&ceil"},
     changenr={},
     chanclose={args={1, 2}},

src/nvim/testdir/test_functions.vim

@@ -852,7 +852,7 @@ func Test_byte2line_line2byte()
 
   set fileformat=mac
   call assert_equal([-1, -1, 1, 1, 2, 2, 2, 3, 3, -1],
-  \                 map(range(-1, 8), 'byte2line(v:val)'))
+  \                 map(range(-1, 8), 'v:val->byte2line()'))
   call assert_equal([-1, -1, 1, 3, 6, 8, -1],
   \                 map(range(-1, 5), 'line2byte(v:val)'))
 
@@ -875,6 +875,34 @@ func Test_byte2line_line2byte()
   bw!
 endfunc
 
+func Test_byteidx()
+  let a = '.é.' " one char of two bytes
+  call assert_equal(0, byteidx(a, 0))
+  call assert_equal(0, byteidxcomp(a, 0))
+  call assert_equal(1, byteidx(a, 1))
+  call assert_equal(1, byteidxcomp(a, 1))
+  call assert_equal(3, byteidx(a, 2))
+  call assert_equal(3, byteidxcomp(a, 2))
+  call assert_equal(4, byteidx(a, 3))
+  call assert_equal(4, byteidxcomp(a, 3))
+  call assert_equal(-1, byteidx(a, 4))
+  call assert_equal(-1, byteidxcomp(a, 4))
+
+  let b = '.é.' " normal e with composing char
+  call assert_equal(0, b->byteidx(0))
+  call assert_equal(1, b->byteidx(1))
+  call assert_equal(4, b->byteidx(2))
+  call assert_equal(5, b->byteidx(3))
+  call assert_equal(-1, b->byteidx(4))
+
+  call assert_equal(0, b->byteidxcomp(0))
+  call assert_equal(1, b->byteidxcomp(1))
+  call assert_equal(2, b->byteidxcomp(2))
+  call assert_equal(4, b->byteidxcomp(3))
+  call assert_equal(5, b->byteidxcomp(4))
+  call assert_equal(-1, b->byteidxcomp(5))
+endfunc
+
 " Test for charidx()
 func Test_charidx()
   let a = 'xáb́y'
@@ -1476,6 +1504,7 @@ endfunc
 
 func Test_call()
   call assert_equal(3, call('len', [123]))
+  call assert_equal(3, 'len'->call([123]))
   call assert_fails("call call('len', 123)", 'E714:')
   call assert_equal(0, call('', []))
 
@@ -1483,6 +1512,7 @@ func Test_call()
      return len(self.data)
   endfunction
   let mydict = {'data': [0, 1, 2, 3], 'len': function("Mylen")}
+  eval mydict.len->call([], mydict)->assert_equal(4)
   call assert_fails("call call('Mylen', [], 0)", 'E715:')
 endfunc