feat(eval/method): partially port v8.1.1925

Adds method call support for all functions in the patch, but it cannot
be fully ported due to missing tests for:

- getcwd(): requires chdir() and Test_chdir_func() from v8.1.1291.

Note that the method call tests for getreg() and getregtype() were
removed in v8.2.1547, which has already been ported, but doesn't seem to
have been replaced with a new test...

This patch also makes getchangelist()'s argument optional (defaults to
the current buffer).

eval.txt includes a typo for gettabwinvar(), which is fixed in
v8.1.1952.

13 files changed, 107 insertions, 44 deletions

diff --git a/runtime/doc/eval.txt b/runtime/doc/eval.txt
index 832fc6bc1b..24b6e6da6d 100644
--- a/runtime/doc/eval.txt
+++ b/runtime/doc/eval.txt
@@ -4701,6 +4701,9 @@ getbufline({buf}, {lnum} [, {end}])
 		Example: >
 			:let lines = getbufline(bufnr("myfile"), 1, "$")
 
+<		Can also be used as a |method|: >
+			GetBufnr()->getbufline(lnum)
+
 getbufvar({buf}, {varname} [, {def}])				*getbufvar()*
 		The result is the value of option or local buffer variable
 		{varname} in buffer {buf}.  Note that the name without "b:"
@@ -4721,8 +4724,11 @@ getbufvar({buf}, {varname} [, {def}])				*getbufvar()*
 		Examples: >
 			:let bufmodified = getbufvar(1, "&mod")
 			:echo "todo myvar = " . getbufvar("todo", "myvar")
+
+<		Can also be used as a |method|: >
+			GetBufnr()->getbufvar(varname)
 <
-getchangelist({buf})					*getchangelist()*
+getchangelist([{buf}])					*getchangelist()*
 		Returns the |changelist| for the buffer {buf}. For the use
 		of {buf}, see |bufname()| above. If buffer {buf} doesn't
 		exist, an empty list is returned.
@@ -4738,6 +4744,9 @@ getchangelist({buf})					*getchangelist()*
 		position refers to the position in the list. For other
 		buffers, it is set to the length of the list.
 
+		Can also be used as a |method|: >
+			GetBufnr()->getchangelist()
+
 getchar([expr])						*getchar()*
 		Get a single character from the user or input stream.
 		If [expr] is omitted, wait until a character is available.
@@ -4948,6 +4957,9 @@ getcompletion({pat}, {type} [, {filtered}])		*getcompletion()*
 		If there are no matches, an empty list is returned.  An
 		invalid value for {type} produces an error.
 
+		Can also be used as a |method|: >
+			GetPattern()->getcompletion('color')
+<
 							*getcurpos()*
 getcurpos()	Get the position of the cursor.  This is like getpos('.'), but
 		includes an extra "curswant" in the list:
@@ -4976,6 +4988,9 @@ getcwd([{winnr}[, {tabnr}]])				*getcwd()*
 <		If {winnr} is -1 it is ignored, only the tab is resolved.
 		{winnr} can be the window number or the |window-ID|.
 
+		Can also be used as a |method|: >
+			GetWinnr()->getcwd()
+
 getenv({name})						*getenv()*
 		Return the value of environment variable {name}.  The {name}
 		argument is a string, without a leading '$'.  Example: >
@@ -4985,6 +5000,9 @@ getenv({name})						*getenv()*
 		is different from a variable set to an empty string.
 		See also |expr-env|.
 
+		Can also be used as a |method|: >
+			GetVarname()->getenv()
+
 getfontname([{name}])					*getfontname()*
 		Without an argument returns the name of the normal font being
 		used.  Like what is used for the Normal highlight group
@@ -5012,6 +5030,9 @@ getfperm({fname})					*getfperm()*
 <		This will hopefully (from a security point of view) display
 		the string "rw-r--r--" or even "rw-------".
 
+		Can also be used as a |method|: >
+			GetFilename()->getfperm()
+<
 		For setting permissions use |setfperm()|.
 
 getfsize({fname})					*getfsize()*
@@ -5022,6 +5043,9 @@ getfsize({fname})					*getfsize()*
 		If the size of {fname} is too big to fit in a Number then -2
 		is returned.
 
+		Can also be used as a |method|: >
+			GetFilename()->getfsize()
+
 getftime({fname})					*getftime()*
 		The result is a Number, which is the last modification time of
 		the given file {fname}.  The value is measured as seconds
@@ -5029,6 +5053,9 @@ getftime({fname})					*getftime()*
 		|localtime()| and |strftime()|.
 		If the file {fname} can't be found -1 is returned.
 
+		Can also be used as a |method|: >
+			GetFilename()->getftime()
+
 getftype({fname})					*getftype()*
 		The result is a String, which is a description of the kind of
 		file of the given file {fname}.
@@ -5049,6 +5076,9 @@ getftype({fname})					*getftype()*
 		systems that support it.  On some systems only "dir" and
 		"file" are returned.
 
+		Can also be used as a |method|: >
+			GetFilename()->getftype()
+
 getjumplist([{winnr} [, {tabnr}]])			*getjumplist()*
 		Returns the |jumplist| for the specified window.
 
@@ -5068,7 +5098,10 @@ getjumplist([{winnr} [, {tabnr}]])			*getjumplist()*
 			filename	filename if available
 			lnum		line number
 
-							*getline()*
+		Can also be used as a |method|: >
+			GetWinnr()->getjumplist()
+
+<							*getline()*
 getline({lnum} [, {end}])
 		Without {end} the result is a String, which is line {lnum}
 		from the current buffer.  Example: >
@@ -5091,6 +5124,9 @@ getline({lnum} [, {end}])
 			:let end = search("^$") - 1
 			:let lines = getline(start, end)
 
+<		Can also be used as a |method|: >
+			ComputeLnum()->getline()
+
 <		To get lines from another buffer see |getbufline()|
 
 getloclist({nr},[, {what}])				*getloclist()*
@@ -5221,6 +5257,8 @@ getpos({expr})	Get the position for String {expr}.  For possible values of
 			call setpos("'a", save_a_mark)
 <		Also see |getcurpos()| and |setpos()|.
 
+		Can also be used as a |method|: >
+			GetMark()->getpos()
 
 getqflist([{what}])					*getqflist()*
 		Returns a |List| with all the current quickfix errors.  Each
@@ -5339,6 +5377,9 @@ getreg([{regname} [, 1 [, {list}]]])			*getreg()*
 
 		If {regname} is not specified, |v:register| is used.
 
+		Can also be used as a |method|: >
+			GetRegname()->getreg()
+
 getreginfo([{regname}])					*getreginfo()*
 		Returns detailed information about register {regname} as a
 		Dictionary with the following entries:
@@ -5377,6 +5418,9 @@ getregtype([{regname}])					*getregtype()*
 		The {regname} argument is a string.  If {regname} is not
 		specified, |v:register| is used.
 
+		Can also be used as a |method|: >
+			GetRegname()->getregtype()
+
 gettabinfo([{tabnr}])					*gettabinfo()*
 		If {tabnr} is not specified, then information about all the
 		tab pages is returned as a |List|. Each List item is a
@@ -5390,6 +5434,9 @@ gettabinfo([{tabnr}])					*gettabinfo()*
 					tabpage-local variables
 			windows		List of |window-ID|s in the tab page.
 
+		Can also be used as a |method|: >
+			GetTabnr()->gettabinfo()
+
 gettabvar({tabnr}, {varname} [, {def}])				*gettabvar()*
 		Get the value of a tab-local variable {varname} in tab page
 		{tabnr}. |t:var|
@@ -5400,6 +5447,9 @@ gettabvar({tabnr}, {varname} [, {def}])				*gettabvar()*
 		When the tab or variable doesn't exist {def} or an empty
 		string is returned, there is no error message.
 
+		Can also be used as a |method|: >
+			GetTabnr()->gettabvar(varname)
+
 gettabwinvar({tabnr}, {winnr}, {varname} [, {def}])		*gettabwinvar()*
 		Get the value of window-local variable {varname} in window
 		{winnr} in tab page {tabnr}.
@@ -5426,6 +5476,9 @@ gettabwinvar({tabnr}, {winnr}, {varname} [, {def}])		*gettabwinvar()*
 		To obtain all window-local variables use: >
 			gettabwinvar({tabnr}, {winnr}, '&')
 
+<		Can also be used as a |method|: >
+			GetTabnr()->gettabvar(winnr, varname)
+
 gettagstack([{winnr}])					*gettagstack()*
 		The result is a Dict, which is the tag stack of window {winnr}.
 		{winnr} can be the window number or the |window-ID|.
@@ -8339,6 +8392,9 @@ setfperm({fname}, {mode})				*setfperm()* *chmod*
 
 		Returns non-zero for success, zero for failure.
 
+		Can also be used as a |method|: >
+			GetFilename()->setfperm(mode)
+<
 		To read permissions see |getfperm()|.
 
 setline({lnum}, {text})					*setline()*
diff --git a/src/nvim/eval.lua b/src/nvim/eval.lua
index f9f6af3bfd..83a72cc233 100644
--- a/src/nvim/eval.lua
+++ b/src/nvim/eval.lua
@@ -137,9 +137,9 @@ return {
     garbagecollect={args={0, 1}},
     get={args={2, 3}, base=1},
     getbufinfo={args={0, 1}},
-    getbufline={args={2, 3}},
-    getbufvar={args={2, 3}},
-    getchangelist={args={1, 1}},
+    getbufline={args={2, 3}, base=1},
+    getbufvar={args={2, 3}, base=1},
+    getchangelist={args={0, 1}, base=1},
     getchar={args={0, 1}},
     getcharmod={},
     getcharsearch={},
@@ -148,30 +148,30 @@ return {
     getcmdpos={},
     getcmdtype={},
     getcmdwintype={},
-    getcompletion={args={2, 3}},
+    getcompletion={args={2, 3}, base=1},
     getcurpos={},
-    getcwd={args={0,2}},
-    getenv={args={1}},
+    getcwd={args={0, 2}, base=1},
+    getenv={args={1}, base=1},
     getfontname={args={0, 1}},
-    getfperm={args=1},
-    getfsize={args=1},
-    getftime={args=1},
-    getftype={args=1},
-    getjumplist={args={0, 2}},
-    getline={args={1, 2}},
+    getfperm={args=1, base=1},
+    getfsize={args=1, base=1},
+    getftime={args=1, base=1},
+    getftype={args=1, base=1},
+    getjumplist={args={0, 2}, base=1},
+    getline={args={1, 2}, base=1},
     getloclist={args={1, 2}},
     getmarklist={args={0, 1}},
     getmatches={args={0, 1}},
     getmousepos={},
     getpid={},
-    getpos={args=1},
+    getpos={args=1, base=1},
     getqflist={args={0, 1}},
-    getreg={args={0, 3}},
+    getreg={args={0, 3}, base=1},
     getreginfo={args={0, 1}, base=1},
-    getregtype={args={0, 1}},
-    gettabinfo={args={0, 1}},
-    gettabvar={args={2, 3}},
-    gettabwinvar={args={3, 4}},
+    getregtype={args={0, 1}, base=1},
+    gettabinfo={args={0, 1}, base=1},
+    gettabvar={args={2, 3}, base=1},
+    gettabwinvar={args={3, 4}, base=1},
     gettagstack={args={0, 1}},
     getwininfo={args={0, 1}},
     getwinpos={args={0, 1}},
@@ -311,7 +311,7 @@ return {
     setcharsearch={args=1},
     setcmdpos={args=1},
     setenv={args=2},
-    setfperm={args=2},
+    setfperm={args=2, base=1},
     setline={args=2},
     setloclist={args={2, 4}},
     setmatches={args={1, 2}},
diff --git a/src/nvim/eval/funcs.c b/src/nvim/eval/funcs.c
index 5569d74413..b53b50e766 100644
--- a/src/nvim/eval/funcs.c
+++ b/src/nvim/eval/funcs.c
@@ -3088,10 +3088,16 @@ f_getbufvar_end:
 static void f_getchangelist(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 {
   tv_list_alloc_ret(rettv, 2);
-  vim_ignored = tv_get_number(&argvars[0]);  // issue errmsg if type error
-  emsg_off++;
-  const buf_T *const buf = tv_get_buf(&argvars[0], false);
-  emsg_off--;
+
+  const buf_T *buf;
+  if (argvars[0].v_type == VAR_UNKNOWN) {
+    buf = curbuf;
+  } else {
+    vim_ignored = tv_get_number(&argvars[0]);  // issue errmsg if type error
+    emsg_off++;
+    buf = tv_get_buf(&argvars[0], false);
+    emsg_off--;
+  }
   if (buf == NULL) {
     return;
   }
diff --git a/src/nvim/testdir/test_bufline.vim b/src/nvim/testdir/test_bufline.vim
index 52a60b7b85..765ae17736 100644
--- a/src/nvim/testdir/test_bufline.vim
+++ b/src/nvim/testdir/test_bufline.vim
@@ -21,7 +21,7 @@ func Test_setbufline_getbufline()
   call assert_equal(1, setbufline(b, 5, ['x']))
   call assert_equal(1, setbufline(1234, 1, ['x']))
   call assert_equal(0, setbufline(b, 4, ['d', 'e']))
-  call assert_equal(['c'], getbufline(b, 3))
+  call assert_equal(['c'], b->getbufline(3))
   call assert_equal(['d'], getbufline(b, 4))
   call assert_equal(['e'], getbufline(b, 5))
   call assert_equal([], getbufline(b, 6))
diff --git a/src/nvim/testdir/test_bufwintabinfo.vim b/src/nvim/testdir/test_bufwintabinfo.vim
index 4b5b55e6bf..b0258547b8 100644
--- a/src/nvim/testdir/test_bufwintabinfo.vim
+++ b/src/nvim/testdir/test_bufwintabinfo.vim
@@ -88,7 +88,7 @@ function Test_getbufwintabinfo()
     call assert_equal(2, tablist[1].tabnr)
     call assert_equal('build', tablist[0].variables.space)
     call assert_equal(w2_id, tablist[0].windows[0])
-    call assert_equal([], gettabinfo(3))
+    call assert_equal([], 3->gettabinfo())
 
     tabonly | only
 
@@ -106,7 +106,7 @@ function Test_getbufwintabinfo()
 endfunction
 
 function Test_get_buf_options()
-  let opts = getbufvar(bufnr('%'), '&')
+  let opts = bufnr()->getbufvar('&')
   call assert_equal(v:t_dict, type(opts))
   call assert_equal(8, opts.tabstop)
 endfunc
diff --git a/src/nvim/testdir/test_changelist.vim b/src/nvim/testdir/test_changelist.vim
index dd6ea9600c..ce77c1f3c7 100644
--- a/src/nvim/testdir/test_changelist.vim
+++ b/src/nvim/testdir/test_changelist.vim
@@ -8,8 +8,8 @@ func Test_getchangelist()
 
   bwipe!
   enew
-  call assert_equal([], getchangelist(10))
-  call assert_equal([[], 0], getchangelist('%'))
+  call assert_equal([], 10->getchangelist())
+  call assert_equal([[], 0], getchangelist())
 
   call writefile(['line1', 'line2', 'line3'], 'Xfile1.txt')
   call writefile(['line1', 'line2', 'line3'], 'Xfile2.txt')
diff --git a/src/nvim/testdir/test_cmdline.vim b/src/nvim/testdir/test_cmdline.vim
index 5a6824b5c1..ffca415282 100644
--- a/src/nvim/testdir/test_cmdline.vim
+++ b/src/nvim/testdir/test_cmdline.vim
@@ -260,7 +260,7 @@ func Test_getcompletion()
   endif
   let groupcount = len(getcompletion('', 'event'))
   call assert_true(groupcount > 0)
-  let matchcount = len(getcompletion('File', 'event'))
+  let matchcount = len('File'->getcompletion('event'))
   call assert_true(matchcount > 0)
   call assert_true(groupcount > matchcount)
 
diff --git a/src/nvim/testdir/test_edit.vim b/src/nvim/testdir/test_edit.vim
index e1393e875b..2b389c015f 100644
--- a/src/nvim/testdir/test_edit.vim
+++ b/src/nvim/testdir/test_edit.vim
@@ -201,11 +201,11 @@ func Test_edit_07()
   endfu
   au InsertCharPre <buffer> :call DoIt()
   call feedkeys("A\<f5>\<c-p>u\<cr>\<c-l>\<cr>", 'tx')
-  call assert_equal(["Jan\<c-l>",''], getline(1,'$'))
+  call assert_equal(["Jan\<c-l>",''], 1->getline('$'))
   %d
   call setline(1, 'J')
   call feedkeys("A\<f5>\<c-p>u\<down>\<c-l>\<cr>", 'tx')
-  call assert_equal(["January"], getline(1,'$'))
+  call assert_equal(["January"], 1->getline('$'))
 
   delfu ListMonths
   delfu DoIt
@@ -348,7 +348,7 @@ func Test_edit_12()
   call cursor(2, 4)
   call feedkeys("R^\<c-d>", 'tnix')
   call assert_equal(["\tabc", "def"], getline(1, '$'))
-  call assert_equal([0, 2, 2, 0], getpos('.'))
+  call assert_equal([0, 2, 2, 0], '.'->getpos())
   %d
   call setline(1, ["\tabc", "\t\tdef"])
   call cursor(2, 2)
diff --git a/src/nvim/testdir/test_environ.vim b/src/nvim/testdir/test_environ.vim
index a25d83753c..cc15b63824 100644
--- a/src/nvim/testdir/test_environ.vim
+++ b/src/nvim/testdir/test_environ.vim
@@ -15,7 +15,7 @@ endfunc
 
 func Test_getenv()
   unlet! $TESTENV
-  call assert_equal(v:null, getenv('TESTENV'))
+  call assert_equal(v:null, 'TESTENV'->getenv())
   let $TESTENV = 'foo'
   call assert_equal('foo', getenv('TESTENV'))
 endfunc
diff --git a/src/nvim/testdir/test_getvar.vim b/src/nvim/testdir/test_getvar.vim
index 3b61d68ebc..e9868c7887 100644
--- a/src/nvim/testdir/test_getvar.vim
+++ b/src/nvim/testdir/test_getvar.vim
@@ -31,7 +31,7 @@ func Test_var()
   let t:other = 777
   let def_list = [4, 5, 6, 7]
   tabrewind
-  call assert_equal([1, 2, 3], gettabvar(3, 'var_list'))
+  call assert_equal([1, 2, 3], 3->gettabvar('var_list'))
   call assert_equal([1, 2, 3], gettabvar(3, 'var_list', def_list))
   call assert_equal({'var_list': [1, 2, 3], 'other': 777}, gettabvar(3, ''))
   call assert_equal({'var_list': [1, 2, 3], 'other': 777},
@@ -61,7 +61,7 @@ func Test_var()
   let def_dict = {'dict2': 'newval'}
   wincmd b
   tabrewind
-  call assert_equal({'dict': 'tabwin'}, gettabwinvar(2, 3, 'var_dict'))
+  call assert_equal({'dict': 'tabwin'}, 2->gettabwinvar(3, 'var_dict'))
   call assert_equal({'dict': 'tabwin'},
 				\ gettabwinvar(2, 3, 'var_dict', def_dict))
   call assert_equal({'var_dict': {'dict': 'tabwin'}}, gettabwinvar(2, 3, ''))
diff --git a/src/nvim/testdir/test_jumplist.vim b/src/nvim/testdir/test_jumplist.vim
index be1af5e705..9cfbbe2029 100644
--- a/src/nvim/testdir/test_jumplist.vim
+++ b/src/nvim/testdir/test_jumplist.vim
@@ -39,7 +39,7 @@ func Test_getjumplist()
   " Traverse the jump list and verify the results
   5
   exe "normal \<C-O>"
-  call assert_equal(2, getjumplist(1)[1])
+  call assert_equal(2, 1->getjumplist()[1])
   exe "normal 2\<C-O>"
   call assert_equal(0, getjumplist(1, 1)[1])
   exe "normal 3\<C-I>"
diff --git a/src/nvim/testdir/test_stat.vim b/src/nvim/testdir/test_stat.vim
index 5b7df33d2c..170358e023 100644
--- a/src/nvim/testdir/test_stat.vim
+++ b/src/nvim/testdir/test_stat.vim
@@ -10,7 +10,7 @@ func CheckFileTime(doSleep)
   let fl = ['Hello World!']
   for fname in fnames
     call writefile(fl, fname)
-    call add(times, getftime(fname))
+    call add(times, fname->getftime())
     if a:doSleep
       sleep 1
     endif
@@ -19,8 +19,8 @@ func CheckFileTime(doSleep)
   let time_correct = (times[0] <= times[1] && times[1] <= times[2])
   if a:doSleep || time_correct
     call assert_true(time_correct, printf('Expected %s <= %s <= %s', times[0], times[1], times[2]))
-    call assert_equal(strlen(fl[0] . "\n"), getfsize(fnames[0]))
-    call assert_equal('file', getftype(fnames[0]))
+    call assert_equal(strlen(fl[0] . "\n"), fnames[0]->getfsize())
+    call assert_equal('file', fnames[0]->getftype())
     call assert_equal('rw-', getfperm(fnames[0])[0:2])
     let result = 1
   endif
diff --git a/test/functional/legacy/file_perm_spec.lua b/test/functional/legacy/file_perm_spec.lua
index 8fdee95e91..ccdbfe0534 100644
--- a/test/functional/legacy/file_perm_spec.lua
+++ b/test/functional/legacy/file_perm_spec.lua
@@ -3,7 +3,7 @@ require('os')
 
 local helpers = require('test.functional.helpers')(after_each)
 local clear, call, eq = helpers.clear, helpers.call, helpers.eq
-local neq, exc_exec = helpers.neq, helpers.exc_exec
+local neq, exc_exec, eval = helpers.neq, helpers.exc_exec, helpers.eval
 
 describe('Test getting and setting file permissions', function()
   local tempfile = helpers.tmpname()
@@ -14,11 +14,12 @@ describe('Test getting and setting file permissions', function()
   end)
 
   it('file permissions', function()
+    -- eval() is used to test VimL method syntax for setfperm() and getfperm()
     eq('', call('getfperm', tempfile))
-    eq(0, call('setfperm', tempfile, 'r--------'))
+    eq(0, eval("'" .. tempfile .. "'->setfperm('r--------')"))
 
     call('writefile', {'one'}, tempfile)
-    eq(9, call('len', call('getfperm', tempfile)))
+    eq(9, eval("len('" .. tempfile .. "'->getfperm())"))
 
     eq(1, call('setfperm', tempfile, 'rwx------'))
     if helpers.is_os('win') then