[ysh language] Remove $f(x) in favor of $[f(x)]

It is more explicit, and doesn't conflict with

    json write (x)

e.g. this difference would be confusing:

    json write $f (x)
    json write $f(x)

This is #1274.

Still TODO: remove @split(x) in favor of @[split(x)]

osh/word_parse.py

@@ -1507,22 +1507,6 @@ def _ReadCompoundWord3(self, lex_mode, eof_type, empty_ok):
         vsub_token = self.cur_token
 
         part = SimpleVarSub(vsub_token, lexer.TokenSliceLeft(vsub_token, 1))  # type: word_part_t
-        if self.token_type == Id.VSub_DollarName:
-          # Look ahead for $strfunc(x)
-          #   $f(x) or --name=$f(x) is allowed
-          #   but "--name=$f(x)" not allowed?  This would BREAK EXISTING CODE.
-          #   It would need a parse option.
-
-          next_id = self.lexer.LookAheadOne(lex_mode)
-          if next_id == Id.Op_LParen:
-            arglist = ArgList.CreateNull(alloc_lists=True)
-            self._ParseInlineCallArgs(arglist)
-            part = word_part.FuncCall(vsub_token, arglist)
-
-            # Unlike @arrayfunc(x), it makes sense to allow $f(1)$f(2)
-            # var a = f(1); var b = f(2); echo $a$b
-            # It's consistent with other uses of $.
-
         w.parts.append(part)
 
       elif self.token_kind == Kind.ExtGlob:

osh/word_parse_test.py

@@ -461,11 +461,6 @@ def testOilSplice(self):
     # Can't have trailing chars
     _assertReadWordFailure(self, '@func().', oil_at=True)
 
-  def testInlineFuncCall(self):
-    _assertReadWord(self, '--foo=$func()', oil_at=True)
-    _assertReadWord(self, '$func()trailer', oil_at=True)
-    _assertReadWord(self, '--foo=$func()trailer', oil_at=True)
-
   def testReadComment(self):
     # Test that we get Id.Op_Newline
     code = 'foo # comment\nbar #comment\n'

spec/bugs.test.sh

@@ -82,10 +82,6 @@ echo DONE
 ## OK mksh/zsh status: 1
 ## STDOUT:
 ## END
-## OK osh status: 0
-## OK osh STDOUT:
-DONE
-## END
 
 #### Function names
 foo$x() {
@@ -97,7 +93,7 @@ foo $x() {
 }
 
 ## status: 2
-## OK mksh/zsh/osh status: 1
+## OK mksh/zsh status: 1
 ## BUG zsh status: 0
 ## STDOUT:
 ## END

spec/hay-isolation.test.sh

@@ -105,7 +105,7 @@ hay eval :result {
 }
 
 const args = result['children'][0]['args']
-write --sep ' ' -- $len(result['children']) @args
+write --sep ' ' -- $[len(result['children'])] @args
 
 ## STDOUT:
 outside

spec/hay.test.sh

@@ -116,21 +116,21 @@ Package one
 echo status=$?
 
 setvar args = _hay()['children'][0]['args']
-write --sep ' ' $len(_hay()['children']) @args
+write --sep ' ' $[len(_hay()['children'])] @args
 
 hay eval :result {
   Package two
   echo status=$?
 }
 
 setvar args = result['children'][0]['args']
-write --sep ' ' $len(result['children']) @args
+write --sep ' ' $[len(result['children'])] @args
 
 Package three
 echo status=$?
 
 setvar args = _hay()['children'][0]['args']
-write --sep ' ' $len(_hay()['children']) $[_hay()['children'][0]['args'][0]]
+write --sep ' ' $[len(_hay()['children'])] $[_hay()['children'][0]['args'][0]]
 
 ## STDOUT:
 status=0
@@ -288,17 +288,17 @@ hay eval :result {
 
   user alice
   # = _hay()
-  write -- $len(_hay()['children'])
+  write -- $[len(_hay()['children'])]
 
   user bob
   setvar result = _hay()
-  write -- $len(_hay()['children'])
+  write -- $[len(_hay()['children'])]
 
 }
 
 # TODO: Should be cleared here
 setvar result = _hay()
-write -- $len(_hay()['children'])
+write -- $[len(_hay()['children'])]
 
 ## STDOUT:
 1
@@ -332,14 +332,14 @@ hay eval :result {
 }
 
 #= result
-write -- 'level 0 children' $len(result['children'])
-write -- 'level 1 children' $len(result['children'][0]['children']) 
+write -- 'level 0 children' $[len(result['children'])]
+write -- 'level 1 children' $[len(result['children'][0]['children'])]
 
 hay eval :result {
   haynode parent foo
   haynode parent bar
 }
-write -- 'level 0 children' $len(result['children'])
+write -- 'level 0 children' $[len(result['children'])]
 
 
 ## STDOUT:
@@ -582,11 +582,11 @@ shvar _DIALECT=sourcehut {
 }
 
 const children = d['children']
-write 'level 0 children' $len(children) ---
+write 'level 0 children' $[len(children)] ---
 
 # TODO: Do we need @[] for array expression sub?
-write 'child 0' $[children[0]->type] $join(children[0]->args) ---
-write 'child 1' $[children[1]->type] $join(children[1]->args) ---
+write 'child 0' $[children[0]->type] $[join(children[0]->args)] ---
+write 'child 1' $[children[1]->type] $[join(children[1]->args)] ---
 
 ## STDOUT:
 level 0 children
@@ -612,8 +612,8 @@ const block = parse_hay(path)
 
 hay define Package
 const d = eval_hay(block)
-write 'level 0 children' $len(d['children'])
-write 'level 1 children' $len(d['children'][1]['children'])
+write 'level 0 children' $[len(d['children'])]
+write 'level 1 children' $[len(d['children'][1]['children'])]
 
 ## STDOUT:
 level 0 children

spec/tea-func.test.sh

@@ -53,8 +53,8 @@ shopt -s parse_tea
 func add(x Int, y=1, z=1+2*3) {
   return x + y + z
 }
-echo $add(3)
-echo $add(3,4)
+echo $[add(3)]
+echo $[add(3,4)]
 ## STDOUT:
 11
 14
@@ -226,7 +226,7 @@ var a = [42, 43]
 var n = %{x: 99, y: 100}
 
 echo ____
-write string $f(0, 1, ...a, c=2, d=3)
+write string $[f(0, 1, ...a, c=2, d=3)]
 
 # Now get a list back
 echo ____
@@ -263,7 +263,7 @@ array
 var f = |x| x+1
 var y = f(0)
 echo $y
-echo $f(42)
+echo $[f(42)]
 ## STDOUT:
 1
 43

spec/ysh-array.test.sh

@@ -2,7 +2,7 @@
 
 #### basic array
 var x = %(1 2 3)
-write len=$len(x)
+write len=$[len(x)]
 ## STDOUT:
 len=3
 ## END
@@ -12,7 +12,7 @@ shopt -s oil:all
 
 var x = 1
 var a = %($x $(write hi) 'sq' "dq $x")
-write len=$len(a)
+write len=$[len(a)]
 write @a
 ## STDOUT:
 len=4

spec/ysh-bugs.test.sh

@@ -28,7 +28,7 @@ var d = {data: 'foo'}
 echo $[d->data]
 
 var e = {enum: 1, class: 2, import: 3, const: 4, var: 5, set: 6}
-echo $len(e)
+echo $[len(e)]
 
 ## STDOUT:
 foo

spec/ysh-expr.test.sh

@@ -90,16 +90,16 @@ echo shell=${#x[@]}
 
 # Oil function call: length is 20.  I think that makes sense?  It's just a
 # different notion of length.
-echo oil=$len(x)
+echo oil=$[len(x)]
 
 ## STDOUT:
 shell=5
 oil=21
 ## END
 
-#### $len(x) inside strings
+#### $[len(x)] inside strings
 var s = "abc"
-echo -$len(s)-
+echo -$[len(s)]-
 
 # This already has a meaning ...
 #echo "-$len(x)-"
@@ -111,7 +111,7 @@ echo -$len(s)-
 
 #### Func with multiple args in multiple contexts
 var x = max(1+2, 3+4)
-echo $x $max(1+2, 3+4)
+echo $x $[max(1+2, 3+4)]
 
 ## STDOUT:
 7 7
@@ -120,7 +120,7 @@ echo $x $max(1+2, 3+4)
 
 #### Trailing Comma in Param list
 var x = max(1+2, 3+4,)
-echo $x $max(1+2, 3+4,)
+echo $x $[max(1+2, 3+4,)]
 
 ## STDOUT:
 7 7
@@ -130,7 +130,7 @@ echo $x $max(1+2, 3+4,)
 var s = "123"
 
 # lex_mode_e.ShCommand -> Expr -> ShCommand -> Expr
-var x = $(echo $'len\n' $len(s))
+var x = $(echo $'len\n' $[len(s)])
 echo $x
 ## STDOUT:
 len 3
@@ -398,9 +398,9 @@ great
 var zero = ()
 var one = tup(42)
 var two = (1,2)
-echo $len(zero)
-echo $len(one)
-echo $len(two)
+echo $[len(zero)]
+echo $[len(one)]
+echo $[len(two)]
 ## STDOUT:
 0
 1
@@ -423,11 +423,11 @@ true
 
 #### dict with 'bare word' keys
 var d0 = {}
-echo len=$len(d0)
+echo len=$[len(d0)]
 var d1 = {name: "hello"}
-echo len=$len(d1)
+echo len=$[len(d1)]
 var d2 = {name: "hello", other: 2}
-echo len=$len(d2)
+echo len=$[len(d2)]
 ## STDOUT:
 len=0
 len=1
@@ -436,13 +436,13 @@ len=2
 
 #### dict with expression keys
 var d1 = {['name']: "hello"}
-echo len=$len(d1)
+echo len=$[len(d1)]
 var v = d1['name']
 echo $v
 
 var key='k'
 var d2 = {["$key"]: "bar"}
-echo len=$len(d2)
+echo len=$[len(d2)]
 var v2 = d2['k']
 echo $v2
 
@@ -457,12 +457,12 @@ bar
 #### dict literal with implicit value
 var name = 'foo'
 var d1 = {name}
-echo len=$len(d1)
+echo len=$[len(d1)]
 var v1 = d1['name']
 echo $v1
 
 var d2 = {name, other: 'val'}
-echo len=$len(d2)
+echo len=$[len(d2)]
 var v2 = d2['name']
 echo $v2
 
@@ -548,24 +548,24 @@ var dq = "
 dq
 2
 "
-echo dq=$len(dq)
+echo dq=$[len(dq)]
 
 var sq = '
 sq
 2
 '
-echo sq=$len(sq)
+echo sq=$[len(sq)]
 
 var mylist = [
   1,
   2,
   3,
 ]
-echo mylist=$len(mylist)
+echo mylist=$[len(mylist)]
 
 var mytuple = (1,
   2, 3)
-echo mytuple=$len(mytuple)
+echo mytuple=$[len(mytuple)]
 
 ## STDOUT:
 dq=6
@@ -582,7 +582,7 @@ mytuple=3
 var mydict = { a:1,
   b: 2,
 }
-echo mydict=$len(mydict)
+echo mydict=$[len(mydict)]
 ## STDOUT:
 mydict=2
 ## END
@@ -593,13 +593,13 @@ var array = %(
   two
   three
 )
-echo array=$len(array)
+echo array=$[len(array)]
 
 var comsub = $(
 echo hi
 echo bye
 )
-echo comsub=$len(comsub)
+echo comsub=$[len(comsub)]
 
 ## STDOUT:
 array=3
@@ -640,7 +640,7 @@ echo $k
 var a = [1, 2]
 var b = [3]
 var c = a ++ b
-echo len=$len(c)
+echo len=$[len(c)]
 
 ## STDOUT:
 abcde