feat(eval/method): partially port v8.1.2004

Problem:    More functions can be used as methods.
Solution:   Make various functions usable as a method.
https://github.com/vim/vim/commit/f6ed61e1489e40eada55a4f1782e1ed82bcad7d9

+sound is needed for sound_* functions.

Make swapinfo and swapname take exactly one argument.
Previously, they could erroneously take one or more.

9 files changed, 82 insertions, 39 deletions

diff --git a/runtime/doc/eval.txt b/runtime/doc/eval.txt
index bbd3226d4c..fcaed24b1f 100644
--- a/runtime/doc/eval.txt
+++ b/runtime/doc/eval.txt
@@ -9254,6 +9254,9 @@ soundfold({word})
 		This can be used for making spelling suggestions.  Note that
 		the method can be quite slow.
 
+		Can also be used as a |method|: >
+			GetWord()->soundfold()
+<
 							*spellbadword()*
 spellbadword([{sentence}])
 		Without argument: The result is the badly spelled word under
@@ -9279,6 +9282,9 @@ spellbadword([{sentence}])
 		The spelling information for the current window and the value
 		of 'spelllang' are used.
 
+		Can also be used as a |method|: >
+			GetText()->spellbadword()
+<
 							*spellsuggest()*
 spellsuggest({word} [, {max} [, {capital}]])
 		Return a |List| with spelling suggestions to replace {word}.
@@ -9301,6 +9307,8 @@ spellsuggest({word} [, {max} [, {capital}]])
 		The spelling information for the current window is used.  The
 		values of 'spelllang' and 'spellsuggest' are used.
 
+		Can also be used as a |method|: >
+			GetWord()->spellsuggest()
 
 split({string} [, {pattern} [, {keepempty}]])			*split()*
 		Make a |List| out of {string}.  When {pattern} is omitted or
@@ -9432,6 +9440,20 @@ str2nr({string} [, {base}])			*str2nr()*
 		{base} is 2 a leading "0b" or "0B" is ignored.
 		Text after the number is silently ignored.
 
+		Can also be used as a |method|: >
+			GetText()->str2nr()
+
+strcharpart({src}, {start} [, {len}])			*strcharpart()*
+		Like |strpart()| but using character index and length instead
+		of byte index and length.  Composing characters are counted
+		separately.
+		When a character index is used where a character does not
+		exist it is assumed to be one character.  For example: >
+			strcharpart('abc', -1, 2)
+<		results in 'a'.
+
+		Can also be used as a |method|: >
+			GetText()->strcharpart(5)
 
 strchars({string} [, {skipcc}])					*strchars()*
 		The result is a Number, which is the number of characters
@@ -9457,14 +9479,8 @@ strchars({string} [, {skipcc}])					*strchars()*
 		      endfunction
 		    endif
 <
-strcharpart({src}, {start} [, {len}])			*strcharpart()*
-		Like |strpart()| but using character index and length instead
-		of byte index and length.  Composing characters are counted
-		separately.
-		When a character index is used where a character does not
-		exist it is assumed to be one character.  For example: >
-			strcharpart('abc', -1, 2)
-<		results in 'a'.
+		Can also be used as a |method|: >
+			GetText()->strchars()
 
 strdisplaywidth({string} [, {col}])			*strdisplaywidth()*
 		The result is a Number, which is the number of display cells
@@ -9479,6 +9495,9 @@ strdisplaywidth({string} [, {col}])			*strdisplaywidth()*
 		Ambiguous, this function's return value depends on 'ambiwidth'.
 		Also see |strlen()|, |strwidth()| and |strchars()|.
 
+		Can also be used as a |method|: >
+			GetText()->strdisplaywidth()
+
 strftime({format} [, {time}])				*strftime()*
 		The result is a String, which is a formatted date and time, as
 		specified by the {format} string.  The given {time} is used,
@@ -9496,12 +9515,18 @@ strftime({format} [, {time}])				*strftime()*
 		  :echo strftime("%c", getftime("file.c"))
 						   Show mod time of file.c.
 
+<		Can also be used as a |method|: >
+			GetFormat()->strftime()
+
 strgetchar({str}, {index})				*strgetchar()*
 		Get character {index} from {str}.  This uses a character
 		index, not a byte index.  Composing characters are considered
 		separate characters here.
 		Also see |strcharpart()| and |strchars()|.
 
+		Can also be used as a |method|: >
+			GetText()->strgetchar(5)
+
 stridx({haystack}, {needle} [, {start}])		*stridx()*
 		The result is a Number, which gives the byte index in
 		{haystack} of the first occurrence of the String {needle}.
@@ -9521,6 +9546,9 @@ stridx({haystack}, {needle} [, {start}])		*stridx()*
 		stridx() works similar to the C function strstr().  When used
 		with a single character it works similar to strchr().
 
+		Can also be used as a |method|: >
+			GetHaystack()->stridx(needle)
+
 							*string()*
 string({expr})	Return {expr} converted to a String.  If {expr} is a Number,
 		Float, String, Blob or a composition of them, then the result
@@ -9583,6 +9611,9 @@ strpart({src}, {start} [, {len} [, {chars}]])			*strpart()*
 		example, to get the character under the cursor: >
 			strpart(getline("."), col(".") - 1, 1, v:true)
 <
+		Can also be used as a |method|: >
+			GetText()->strpart(5)
+
 strptime({format}, {timestring})				*strptime()*
 		The result is a Number, which is a unix timestamp representing
 		the date and time in {timestring}, which is expected to match
@@ -9626,6 +9657,9 @@ strridx({haystack}, {needle} [, {start}])			*strridx()*
 		When used with a single character it works similar to the C
 		function strrchr().
 
+		Can also be used as a |method|: >
+			GetHaystack()->strridx(needle)
+
 strtrans({string})					*strtrans()*
 		The result is a String, which is {string} with all unprintable
 		characters translated into printable characters |'isprint'|.
@@ -9674,6 +9708,9 @@ submatch({nr} [, {list}])			*submatch()* *E935*
 <		This finds the first number in the line and adds one to it.
 		A line break is included as a newline character.
 
+		Can also be used as a |method|: >
+			GetNr()->submatch()
+
 substitute({string}, {pat}, {sub}, {flags})		*substitute()*
 		The result is a String, which is a copy of {string}, in which
 		the first match of {pat} is replaced with {sub}.
@@ -9736,6 +9773,9 @@ swapinfo({fname})					*swapinfo()*
 			Not a swap file: does not contain correct block ID
 			Magic number mismatch: Info in first block is invalid
 
+		Can also be used as a |method|: >
+			GetFilename()->swapinfo()
+
 swapname({buf})						*swapname()*
 		The result is the swap file path of the buffer {buf}.
 		For the use of {buf}, see |bufname()| above.
@@ -9743,6 +9783,9 @@ swapname({buf})						*swapname()*
 		|:swapname| (unless there is no swap file).
 		If buffer {buf} has no swap file, returns an empty string.
 
+		Can also be used as a |method|: >
+			GetBufname()->swapname()
+
 synID({lnum}, {col}, {trans})				*synID()*
 		The result is a Number, which is the syntax ID at the position
 		{lnum} and {col} in the current window.
diff --git a/src/nvim/eval.lua b/src/nvim/eval.lua
index 6a800e5648..2a12a4d119 100644
--- a/src/nvim/eval.lua
+++ b/src/nvim/eval.lua
@@ -340,33 +340,33 @@ return {
     sinh={args=1, base=1, func="float_op_wrapper", data="&sinh"},
     sockconnect={args={2,3}},
     sort={args={1, 3}, base=1},
-    soundfold={args=1},
+    soundfold={args=1, base=1},
     stdioopen={args=1},
-    spellbadword={args={0, 1}},
-    spellsuggest={args={1, 3}},
+    spellbadword={args={0, 1}, base=1},
+    spellsuggest={args={1, 3}, base=1},
     split={args={1, 3}, base=1},
     sqrt={args=1, base=1, func="float_op_wrapper", data="&sqrt"},
     stdpath={args=1},
     str2float={args=1, base=1},
     str2list={args={1, 2}, base=1},
-    str2nr={args={1, 3}},
-    strcharpart={args={2, 3}},
-    strchars={args={1,2}},
-    strdisplaywidth={args={1, 2}},
-    strftime={args={1, 2}},
-    strgetchar={args={2, 2}},
-    stridx={args={2, 3}},
+    str2nr={args={1, 3}, base=1},
+    strcharpart={args={2, 3}, base=1},
+    strchars={args={1, 2}, base=1},
+    strdisplaywidth={args={1, 2}, base=1},
+    strftime={args={1, 2}, base=1},
+    strgetchar={args=2, base=1},
+    stridx={args={2, 3}, base=1},
     string={args=1, base=1},
     strlen={args=1, base=1},
-    strpart={args={2, 4}},
+    strpart={args={2, 4}, base=1},
     strptime={args=2},
-    strridx={args={2, 3}},
+    strridx={args={2, 3}, base=1},
     strtrans={args=1, base=1},
     strwidth={args=1, base=1},
-    submatch={args={1, 2}},
+    submatch={args={1, 2}, base=1},
     substitute={args=4, base=1},
-    swapinfo={args={1}},
-    swapname={args={1}},
+    swapinfo={args=1, base=1},
+    swapname={args=1, base=1},
     synID={args=3},
     synIDattr={args={2, 3}, base=1},
     synIDtrans={args=1, base=1},
diff --git a/src/nvim/testdir/test_breakindent.vim b/src/nvim/testdir/test_breakindent.vim
index 277050876e..8d592f21ea 100644
--- a/src/nvim/testdir/test_breakindent.vim
+++ b/src/nvim/testdir/test_breakindent.vim
@@ -432,7 +432,7 @@ func Test_breakindent11_vartabs()
   call s:test_windows('setl cpo-=n sbr=>> nu nuw=4 nolist briopt= ts=4 vts=4')
   let text = getline(2)
   let width = strlen(text[1:]) + 2->indent() + strlen(&sbr) * 3 " text wraps 3 times
-  call assert_equal(width, strdisplaywidth(text))
+  call assert_equal(width, text->strdisplaywidth())
   call s:close_windows('set sbr= vts&')
 endfunc
 
diff --git a/src/nvim/testdir/test_expr.vim b/src/nvim/testdir/test_expr.vim
index a8cf6577f6..1d7fd3e385 100644
--- a/src/nvim/testdir/test_expr.vim
+++ b/src/nvim/testdir/test_expr.vim
@@ -56,7 +56,7 @@ endfunc
 
 func Test_strgetchar()
   call assert_equal(char2nr('a'), strgetchar('axb', 0))
-  call assert_equal(char2nr('x'), strgetchar('axb', 1))
+  call assert_equal(char2nr('x'), 'axb'->strgetchar(1))
   call assert_equal(char2nr('b'), strgetchar('axb', 2))
 
   call assert_equal(-1, strgetchar('axb', -1))
@@ -66,7 +66,7 @@ endfunc
 
 func Test_strcharpart()
   call assert_equal('a', strcharpart('axb', 0, 1))
-  call assert_equal('x', strcharpart('axb', 1, 1))
+  call assert_equal('x', 'axb'->strcharpart(1, 1))
   call assert_equal('b', strcharpart('axb', 2, 1))
   call assert_equal('xb', strcharpart('axb', 1))
 
diff --git a/src/nvim/testdir/test_functions.vim b/src/nvim/testdir/test_functions.vim
index ef33cd5dd8..472cb46525 100644
--- a/src/nvim/testdir/test_functions.vim
+++ b/src/nvim/testdir/test_functions.vim
@@ -143,7 +143,7 @@ func Test_str2nr()
   call assert_equal(-123456789, str2nr('-123456789'))
 
   call assert_equal(5, str2nr('101', 2))
-  call assert_equal(5, str2nr('0b101', 2))
+  call assert_equal(5, '0b101'->str2nr(2))
   call assert_equal(5, str2nr('0B101', 2))
   call assert_equal(-5, str2nr('-101', 2))
   call assert_equal(-5, str2nr('-0b101', 2))
@@ -200,7 +200,7 @@ func Test_strftime()
   " of strftime() can be 17 or 18, depending on timezone.
   call assert_match('^2017-01-1[78]$', strftime('%Y-%m-%d', 1484695512))
   "
-  call assert_match('^\d\d\d\d-\(0\d\|1[012]\)-\([012]\d\|3[01]\) \([01]\d\|2[0-3]\):[0-5]\d:\([0-5]\d\|60\)$', strftime('%Y-%m-%d %H:%M:%S'))
+  call assert_match('^\d\d\d\d-\(0\d\|1[012]\)-\([012]\d\|3[01]\) \([01]\d\|2[0-3]\):[0-5]\d:\([0-5]\d\|60\)$', '%Y-%m-%d %H:%M:%S'->strftime())
 
   call assert_fails('call strftime([])', 'E730:')
   call assert_fails('call strftime("%Y", [])', 'E745:')
@@ -375,7 +375,7 @@ endfunc
 func Test_strpart()
   call assert_equal('de', strpart('abcdefg', 3, 2))
   call assert_equal('ab', strpart('abcdefg', -2, 4))
-  call assert_equal('abcdefg', strpart('abcdefg', -2))
+  call assert_equal('abcdefg', 'abcdefg'->strpart(-2))
   call assert_equal('fg', strpart('abcdefg', 5, 4))
   call assert_equal('defg', strpart('abcdefg', 3))
 
@@ -809,11 +809,11 @@ endfunc
 func Test_stridx()
   call assert_equal(-1, stridx('', 'l'))
   call assert_equal(0,  stridx('', ''))
-  call assert_equal(0,  stridx('hello', ''))
+  call assert_equal(0,  'hello'->stridx(''))
   call assert_equal(-1, stridx('hello', 'L'))
   call assert_equal(2,  stridx('hello', 'l', -1))
   call assert_equal(2,  stridx('hello', 'l', 0))
-  call assert_equal(2,  stridx('hello', 'l', 1))
+  call assert_equal(2,  'hello'->stridx('l', 1))
   call assert_equal(3,  stridx('hello', 'l', 3))
   call assert_equal(-1, stridx('hello', 'l', 4))
   call assert_equal(-1, stridx('hello', 'l', 10))
@@ -826,7 +826,7 @@ func Test_strridx()
   call assert_equal(0,  strridx('', ''))
   call assert_equal(5,  strridx('hello', ''))
   call assert_equal(-1, strridx('hello', 'L'))
-  call assert_equal(3,  strridx('hello', 'l'))
+  call assert_equal(3,  'hello'->strridx('l'))
   call assert_equal(3,  strridx('hello', 'l', 10))
   call assert_equal(3,  strridx('hello', 'l', 3))
   call assert_equal(2,  strridx('hello', 'l', 2))
diff --git a/src/nvim/testdir/test_spell.vim b/src/nvim/testdir/test_spell.vim
index e525d06ea2..cf0faeee31 100644
--- a/src/nvim/testdir/test_spell.vim
+++ b/src/nvim/testdir/test_spell.vim
@@ -77,7 +77,7 @@ func Test_spellbadword()
   set spell
 
   call assert_equal(['bycycle', 'bad'],  spellbadword('My bycycle.'))
-  call assert_equal(['another', 'caps'], spellbadword('A sentence. another sentence'))
+  call assert_equal(['another', 'caps'], 'A sentence. another sentence'->spellbadword())
 
   call assert_equal(['TheCamelWord', 'bad'], spellbadword('TheCamelWord asdf'))
   set spelloptions=camel
@@ -407,7 +407,7 @@ func Test_zz_basic()
         \ )
 
   call assert_equal("gebletegek", soundfold('goobledygoook'))
-  call assert_equal("kepereneven", soundfold('kóopërÿnôven'))
+  call assert_equal("kepereneven", 'kóopërÿnôven'->soundfold())
   call assert_equal("everles gesvets etele", soundfold('oeverloos gezwets edale'))
 endfunc
 
@@ -711,7 +711,7 @@ func TestGoodBadBase()
       break
     endif
     let prevbad = bad
-    let lst = spellsuggest(bad, 3)
+    let lst = bad->spellsuggest(3)
     normal mm
 
     call add(result, [bad, lst])
diff --git a/src/nvim/testdir/test_substitute.vim b/src/nvim/testdir/test_substitute.vim
index e7f9bb76f2..f06705a84c 100644
--- a/src/nvim/testdir/test_substitute.vim
+++ b/src/nvim/testdir/test_substitute.vim
@@ -547,7 +547,7 @@ func Test_sub_replace_5()
 		\ substitute('A123456789',
 		\ 'A\(.\)\(.\)\(.\)\(.\)\(.\)\(.\)\(.\)\(.\)\(.\)',
 		\ '\=string([submatch(0, 1), submatch(9, 1), ' .
-		\ 'submatch(8, 1), submatch(7, 1), submatch(6, 1), ' .
+		\ 'submatch(8, 1), 7->submatch(1), submatch(6, 1), ' .
 		\ 'submatch(5, 1), submatch(4, 1), submatch(3, 1), ' .
 		\ 'submatch(2, 1), submatch(1, 1)])',
 		\ ''))
diff --git a/src/nvim/testdir/test_swap.vim b/src/nvim/testdir/test_swap.vim
index e3101d4e44..b3018b2b0d 100644
--- a/src/nvim/testdir/test_swap.vim
+++ b/src/nvim/testdir/test_swap.vim
@@ -113,7 +113,7 @@ func Test_swapinfo()
   w
   let fname = s:swapname()
   call assert_match('Xswapinfo', fname)
-  let info = swapinfo(fname)
+  let info = fname->swapinfo()
 
   let ver = printf('VIM %d.%d', v:version / 100, v:version % 100)
   call assert_equal(ver, info.version)
@@ -155,7 +155,7 @@ func Test_swapname()
   let buf = bufnr('%')
   let expected = s:swapname()
   wincmd p
-  call assert_equal(expected, swapname(buf))
+  call assert_equal(expected, buf->swapname())
 
   new Xtest3
   setlocal noswapfile
diff --git a/src/nvim/testdir/test_utf8.vim b/src/nvim/testdir/test_utf8.vim
index 1f2cdde5cf..0818c2e4b0 100644
--- a/src/nvim/testdir/test_utf8.vim
+++ b/src/nvim/testdir/test_utf8.vim
@@ -17,7 +17,7 @@ func Test_strchars()
   let exp = [[1, 1, 1], [3, 3, 3], [2, 2, 1], [3, 3, 1], [1, 1, 1]]
   for i in range(len(inp))
     call assert_equal(exp[i][0], strchars(inp[i]))
-    call assert_equal(exp[i][1], strchars(inp[i], 0))
+    call assert_equal(exp[i][1], inp[i]->strchars(0))
     call assert_equal(exp[i][2], strchars(inp[i], 1))
   endfor
 endfunc