[ysh breaking] ARGV is a normal List variable

It's not an alias for the "argv stack".

Why?

- There was a bug where mutating ARGV was ignored.  You got a new
  value.List every time.
- Removing the argv stack simplifies a pure YSH runtime (see Zulip)
- Removing the argv stack removes special semantics from the language.
  - ARGV is just a list.
- We are going to get rid of "$@", so there's no reason to be
  constrained by its odd semantics.

Now these are 2 different "worlds":

- shell functions and "$@
- procs and @argv

core/state.py

@@ -961,15 +961,14 @@ def __init__(self, mem, mutable_opts, proc, argv):
         frame = NewDict()  # type: Dict[str, Cell]
 
         assert argv is not None
-        if True:
+        if proc.sh_compat:
             # shell function
             mem.argv_stack.append(_ArgFrame(argv))
         else:
-            # TODO: procs get argv
-            # - open: the args
-            # - closed: always empty
-            #frame['ARGV'] = _MakeArgvCell(argv)
-            pass
+            # procs
+            # - open: is equivalent to ...ARGV
+            # - closed: ARGV is empty list
+            frame['ARGV'] = _MakeArgvCell(argv)
 
         mem.var_stack.append(frame)
 
@@ -982,6 +981,7 @@ def __init__(self, mem, mutable_opts, proc, argv):
         # 'if p' should be allowed.
         self.mem = mem
         self.mutable_opts = mutable_opts
+        self.sh_compat = proc.sh_compat
 
     def __enter__(self):
         # type: () -> None
@@ -993,8 +993,8 @@ def __exit__(self, type, value, traceback):
         self.mem.PopCall()
         self.mem.var_stack.pop()
 
-        # TODO: do this conditionally
-        self.mem.argv_stack.pop()
+        if self.sh_compat:
+            self.mem.argv_stack.pop()
 
 
 class ctx_Temp(object):
@@ -1112,7 +1112,7 @@ def __init__(self, dollar0, argv, arena, debug_stack):
 
         frame = NewDict()  # type: Dict[str, Cell]
 
-        #frame['ARGV'] = _MakeArgvCell(argv)
+        frame['ARGV'] = _MakeArgvCell(argv)
 
         self.var_stack = [frame]
 
@@ -1879,14 +1879,8 @@ def GetValue(self, name, which_scopes=scope_e.Shopt):
         # if name not in COMPUTED_VARS: ...
 
         with str_switch(name) as case:
-            if case('ARGV'):
-                # TODO: ARGV can be a normal mutable variable in YSH
-                items = [value.Str(s)
-                         for s in self.GetArgv()]  # type: List[value_t]
-                return value.List(items)
-
             # "Registers"
-            elif case('_status'):
+            if case('_status'):
                 return num.ToBig(self.TryStatus())
 
             elif case('_error'):

spec/ysh-builtin-module.test.sh

@@ -38,13 +38,13 @@ status=0
 ## END
 
 #### runproc
-shopt --set parse_proc
+shopt --set parse_proc parse_at
 
 f() {
   write -- f "$@"
 }
 proc p {
-  write -- p "$@"
+  write -- p @ARGV
 }
 runproc f 1 2
 echo status=$?

spec/ysh-proc.test.sh

@@ -1,4 +1,4 @@
-## oils_failures_allowed: 1
+## oils_failures_allowed: 0
 
 #### Open proc (any number of args)
 shopt --set parse_proc
@@ -42,7 +42,7 @@ builtin set -- a b c
 foo x y z
 ## STDOUT:
 ARGV x y z
-dollar-at x y z
+dollar-at a b c
 ## END
 
 #### Closed proc has empty "$@" or ARGV
@@ -60,7 +60,7 @@ params
 x
 y
 z
-['dollar-at']
+['dollar-at', 'a', 'b', 'c']
 ['ARGV']
 ## END
 
@@ -157,10 +157,10 @@ p x (:| a b |, {bob: 42}, a = 5)
 ## END
 
 #### Proc name-with-hyphen
-shopt --set parse_proc
+shopt --set parse_proc parse_at
 
 proc name-with-hyphen {
-  echo "$@"
+  echo @ARGV
 }
 name-with-hyphen x y z
 ## STDOUT:
@@ -369,24 +369,24 @@ argv.py @ARGV
 
 set -- 'a b' c
 argv.py "$@"
-argv.py @ARGV
+argv.py @ARGV  # separate from the argv stack
 
 f() {
   argv.py "$@"
-  argv.py @ARGV
+  argv.py @ARGV  # separate from the argv stack
 }
 f 1 '2 3'
 ## STDOUT:
 []
 []
 ['a b', 'c']
-['a b', 'c']
-['1', '2 3']
+[]
 ['1', '2 3']
+[]
 ## END
 
 
-#### Mutating global and local ARGV
+#### Mutating global ARGV
 
 $SH -c '
 shopt -s ysh:upgrade
@@ -396,12 +396,24 @@ argv.py global @ARGV
 # should not be ignored
 call ARGV->append("GG")
 
+argv.py global @ARGV
+'
+## STDOUT:
+['global']
+['global', 'GG']
+## END
+
+#### Mutating local ARGV
+
+$SH -c '
+shopt -s ysh:upgrade
+
 argv.py global @ARGV
 
 proc p {
-  argv.py local @ARGV
+  argv.py @ARGV
   call ARGV->append("LL")
-  argv.py local @ARGV
+  argv.py @ARGV
 }
 
 p local @ARGV
@@ -412,9 +424,8 @@ argv.py global @ARGV
 
 ## STDOUT:
 ['global', 'a b', 'c']
-['global', 'a b', 'c', 'GG']
-['local', 'a b', 'c', 'GG']
-['local', 'a b', 'c', 'GG', 'LL']
-['global', 'a b', 'c', 'GG', 'LL']
+['local', 'a b', 'c']
+['local', 'a b', 'c', 'LL']
+['global', 'a b', 'c']
 ## END
 

spec/ysh-scope.test.sh

@@ -429,12 +429,12 @@ p2 x=
 ## END
 
 #### unset composes when you turn on dynamic scope
-shopt -s oil:all
+shopt -s ysh:all
 
-proc unset-two {
+proc unset-two (v, w) {
   shopt --set dynamic_scope {
-    unset $1 
-    unset $2
+    unset $v
+    unset $w
   }
 }
 

spec/ysh-xtrace.test.sh

@@ -56,15 +56,15 @@ sed --regexp-extended 's/[[:digit:]]{2,}/12345/g' err.txt >&2
 ## END
 
 #### proc and shell function
-shopt --set oil:upgrade
+shopt --set ysh:upgrade
 set -x
 
 shfunc() {
   : $1
 }
 
-proc p {
-  : $1
+proc p (x) {
+  : $x
 }
 
 shfunc 1