feat(eval/method): partially port v8.1.1954

Does not include listener_*() functions.

js_*() functions are N/A.

json_encode() and json_decode() didn't include tests; add some anyway
(to json_functions_spec.lua).

test_lua.vim isn't included yet, so add tests to luaeval_spec.lua.

runtime/doc/eval.txt

@@ -1204,7 +1204,7 @@ next method: >
 	mylist->filter(filterexpr)->map(mapexpr)->sort()->join()
 <
 Example of using a lambda: >
-	GetPercentage->{x -> x * 100}()->printf('%d%%')
+	GetPercentage()->{x -> x * 100}()->printf('%d%%')
 <
 When using -> the |expr7| operators will be applied first, thus: >
 	-1.234->string()
@@ -6384,6 +6384,9 @@ json_decode({expr})					*json_decode()*
 		recommended and the only one required to be supported.
 		Non-UTF-8 characters are an error.
 
+		Can also be used as a |method|: >
+			ReadObject()->json_decode()
+
 json_encode({expr})					*json_encode()*
 		Convert {expr} into a JSON string.  Accepts
 		|msgpack-special-dict| as the input.  Will not convert
@@ -6396,6 +6399,9 @@ json_encode({expr})					*json_encode()*
 		or special escapes like "\t", other are dumped as-is.
 		|Blob|s are converted to arrays of the individual bytes.
 
+		Can also be used as a |method|: >
+			GetObject()->json_encode()
+
 keys({dict})						*keys()*
 		Return a |List| with all the keys of {dict}.  The |List| is in
 		arbitrary order.  Also see |items()| and |values()|.
@@ -6459,6 +6465,10 @@ libcall({libname}, {funcname}, {argument})
 		object code must be compiled as position-independent ('PIC').
 		Examples: >
 			:echo libcall("libc.so", "getenv", "HOME")
+
+<		Can also be used as a |method|, where the base is passed as
+		the argument to the called function: >
+			GetValue()->libcall("libc.so", "getenv")
 <
 							*libcallnr()*
 libcallnr({libname}, {funcname}, {argument})
@@ -6468,6 +6478,10 @@ libcallnr({libname}, {funcname}, {argument})
 			:echo libcallnr("/usr/lib/libc.so", "getpid", "")
 			:call libcallnr("libc.so", "printf", "Hello World!\n")
 			:call libcallnr("libc.so", "sleep", 10)
+<
+		Can also be used as a |method|, where the base is passed as
+		the argument to the called function: >
+			GetValue()->libcallnr("libc.so", "printf")
 <
 							*line()*
 line({expr})	The result is a Number, which is the line number of the file
@@ -6493,6 +6507,9 @@ line({expr})	The result is a Number, which is the line number of the file
 			line(".")		line number of the cursor
 			line("'t")		line number of mark t
 			line("'" . marker)	line number of mark marker
+<
+		Can also be used as a |method|: >
+			GetValue()->line()
 
 line2byte({lnum})					*line2byte()*
 		Return the byte count from the start of the buffer for line
@@ -6507,6 +6524,9 @@ line2byte({lnum})					*line2byte()*
 		|getline()|.  When {lnum} is invalid -1 is returned.
 		Also see |byte2line()|, |go| and |:goto|.
 
+		Can also be used as a |method|: >
+			GetLnum()->line2byte()
+
 lispindent({lnum})					*lispindent()*
 		Get the amount of indent for line {lnum} according the lisp
 		indenting rules, as with 'lisp'.
@@ -6514,6 +6534,9 @@ lispindent({lnum})					*lispindent()*
 		relevant.  {lnum} is used just like in |getline()|.
 		When {lnum} is invalid, -1 is returned.
 
+		Can also be used as a |method|: >
+			GetLnum()->lispindent()
+
 list2str({list} [, {utf8}])				*list2str()*
 		Convert each number in {list} to a character string can
 		concatenate them all.  Examples: >
@@ -6528,6 +6551,9 @@ list2str({list} [, {utf8}])				*list2str()*
 		With utf-8 composing characters work as expected: >
 			list2str([97, 769])	returns "á"
 <
+		Can also be used as a |method|: >
+			GetList()->list2str()
+
 localtime()						*localtime()*
 		Return the current time, measured as seconds since 1st Jan
 		1970.  See also |strftime()|, |strptime()| and |getftime()|.
@@ -6562,6 +6588,9 @@ luaeval({expr}[, {expr}])
 		Evaluate Lua expression {expr} and return its result converted
 		to Vim data structures. See |lua-eval| for more details.
 
+		Can also be used as a |method|: >
+			GetExpr()->luaeval()
+
 map({expr1}, {expr2})					*map()*
 		{expr1} must be a |List|, |Blob| or |Dictionary|.
 		Replace each item in {expr1} with the result of evaluating

src/nvim/eval.lua

@@ -220,21 +220,21 @@ return {
     jobstop={args=1},
     jobwait={args={1, 2}},
     join={args={1, 2}, base=1},
-    json_decode={args=1},
-    json_encode={args=1},
+    json_decode={args=1, base=1},
+    json_encode={args=1, base=1},
     keys={args=1, base=1},
     last_buffer_nr={},  -- obsolete
     len={args=1, base=1},
-    libcall={args=3},
-    libcallnr={args=3},
-    line={args={1, 2}},
-    line2byte={args=1},
-    lispindent={args=1},
-    list2str={args={1, 2}},
+    libcall={args=3, base=3},
+    libcallnr={args=3, base=3},
+    line={args={1, 2}, base=1},
+    line2byte={args=1, base=1},
+    lispindent={args=1, base=1},
+    list2str={args={1, 2}, base=1},
     localtime={},
     log={args=1, base=1, func="float_op_wrapper", data="&log"},
     log10={args=1, base=1, func="float_op_wrapper", data="&log10"},
-    luaeval={args={1, 2}},
+    luaeval={args={1, 2}, base=1},
     map={args=2, base=1},
     maparg={args={1, 4}},
     mapcheck={args={1, 3}},

src/nvim/testdir/test_arglist.vim

@@ -88,7 +88,7 @@ func Test_argadd_empty_curbuf()
   argadd Xargadd
   call assert_equal(curbuf, bufnr('%'))
   call assert_equal('', bufname('%'))
-  call assert_equal(1, line('$'))
+  call assert_equal(1, '$'->line())
   rew
   call assert_notequal(curbuf, '%'->bufnr())
   call assert_equal('Xargadd', '%'->bufname())

src/nvim/testdir/test_functions.vim

@@ -905,7 +905,7 @@ func Test_byte2line_line2byte()
   call assert_equal([-1, -1, 1, 1, 2, 2, 2, 3, 3, -1],
   \                 map(range(-1, 8), 'v:val->byte2line()'))
   call assert_equal([-1, -1, 1, 3, 6, 8, -1],
-  \                 map(range(-1, 5), 'line2byte(v:val)'))
+  \                 map(range(-1, 5), 'v:val->line2byte()'))
 
   set fileformat=dos
   call assert_equal([-1, -1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, -1],
@@ -1505,17 +1505,17 @@ func Test_libcall_libcallnr()
   endif
 
   if has('win32')
-    call assert_equal($USERPROFILE, libcall(libc, 'getenv', 'USERPROFILE'))
+    call assert_equal($USERPROFILE, 'USERPROFILE'->libcall(libc, 'getenv'))
   else
-    call assert_equal($HOME, libcall(libc, 'getenv', 'HOME'))
+    call assert_equal($HOME, 'HOME'->libcall(libc, 'getenv'))
   endif
 
   " If function returns NULL, libcall() should return an empty string.
   call assert_equal('', libcall(libc, 'getenv', 'X_ENV_DOES_NOT_EXIT'))
 
   " Test libcallnr() with string and integer argument.
-  call assert_equal(4, libcallnr(libc, 'strlen', 'abcd'))
-  call assert_equal(char2nr('A'), libcallnr(libc, 'toupper', char2nr('a')))
+  call assert_equal(4, 'abcd'->libcallnr(libc, 'strlen'))
+  call assert_equal(char2nr('A'), char2nr('a')->libcallnr(libc, 'toupper'))
 
   call assert_fails("call libcall(libc, 'Xdoesnotexist_', '')", 'E364:')
   call assert_fails("call libcallnr(libc, 'Xdoesnotexist_', '')", 'E364:')

src/nvim/testdir/test_lispwords.vim

@@ -43,6 +43,9 @@ func Test_lisp_indent()
 	      \ ',@body',
 	      \ '(princ "</a>")))'
 	      \ ])
+  call assert_equal(7, lispindent(2))
+  call assert_equal(5, 6->lispindent())
+
   set lisp
   set lispwords&
   let save_copt = &cpoptions

src/nvim/testdir/test_utf8.vim

@@ -111,7 +111,7 @@ func Test_list2str_str2list_utf8()
   let s = "\u304b\u3099\u3044"
   let l = [0x304b, 0x3099, 0x3044]
   call assert_equal(l, str2list(s, 1))
-  call assert_equal(s, list2str(l, 1))
+  call assert_equal(s, l->list2str(1))
   if &enc ==# 'utf-8'
     call assert_equal(str2list(s), str2list(s, 1))
     call assert_equal(list2str(l), list2str(l, 1))

test/functional/lua/luaeval_spec.lua

@@ -86,14 +86,15 @@ describe('luaeval()', function()
   -- meaningful later.
 
   it('correctly evaluates scalars', function()
+    -- Also test method call (->) syntax
     eq(1, funcs.luaeval('1'))
-    eq(0, eval('type(luaeval("1"))'))
+    eq(0, eval('"1"->luaeval()->type()'))
 
     eq(1.5, funcs.luaeval('1.5'))
-    eq(5, eval('type(luaeval("1.5"))'))
+    eq(5, eval('"1.5"->luaeval()->type()'))
 
     eq("test", funcs.luaeval('"test"'))
-    eq(1, eval('type(luaeval("\'test\'"))'))
+    eq(1, eval('"\'test\'"->luaeval()->type()'))
 
     eq('', funcs.luaeval('""'))
     eq('\000', funcs.luaeval([['\0']]))

test/functional/vimscript/json_functions_spec.lua

@@ -168,7 +168,8 @@ describe('json_decode() function', function()
   end)
 
   it('parses floating-point numbers', function()
-    eq('100000.0', eval('string(json_decode("100000.0"))'))
+    -- Also test method call (->) syntax
+    eq('100000.0', eval('"100000.0"->json_decode()->string()'))
     eq(100000.5, funcs.json_decode('100000.5'))
     eq(-100000.5, funcs.json_decode('-100000.5'))
     eq(-100000.5e50, funcs.json_decode('-100000.5e50'))
@@ -549,11 +550,12 @@ describe('json_encode() function', function()
   end)
 
   it('dumps floats', function()
-    eq('0.0', eval('json_encode(0.0)'))
+    -- Also test method call (->) syntax
+    eq('0.0', eval('0.0->json_encode()'))
     eq('10.5', funcs.json_encode(10.5))
     eq('-10.5', funcs.json_encode(-10.5))
     eq('-1.0e-5', funcs.json_encode(-1e-5))
-    eq('1.0e50', eval('json_encode(1.0e50)'))
+    eq('1.0e50', eval('1.0e50->json_encode()'))
   end)
 
   it('fails to dump NaN and infinite values', function()