[refactor] Simplify loc.OfCommand() using new fields

I'm wondering if we need loc.TokenForCommand() as a helper function

Tokens are the things that point to lines, which we show the user

core/ui.py

@@ -138,6 +138,8 @@ def GetLineSourceString(arena, line, quote_filename=False):
 
     elif case(source_e.ArgvWord):
       src = cast(source.ArgvWord, UP_src)
+
+      # TODO: check loc.Missing; otherwise get Token from loc_t, then line
       span_id = location.GetSpanId(src.location)
       if span_id == runtime.NO_SPID:
         s = '[ %s word at ? ]' % src.what

frontend/location.py

@@ -75,6 +75,7 @@ def GetSpanId(loc_):
 def OfCommand(node):
   # type: (command_t) -> loc_t
   """
+  Used in pipe_locs, for _CheckStatus(), _StrictErrExit, etc.
   """
   UP_node = node # type: command_t
   tag = node.tag()
@@ -88,41 +89,45 @@ def OfCommand(node):
     node = cast(command.Simple, UP_node)
     # It should have either words or redirects, e.g. '> foo'
     if len(node.words):
+      # TODO: need token
       return loc.Word(node.words[0])
     elif len(node.redirects):
       return node.redirects[0].op
 
   if tag == command_e.ShAssignment:
     node = cast(command.ShAssignment, UP_node)
-    return loc.Span(node.spids[0])
+    return node.var
 
+  # TODO: need tokens
   if tag == command_e.Pipeline:
     node = cast(command.Pipeline, UP_node)
     return loc.Span(node.spids[0])  # first |
   if tag == command_e.AndOr:
     node = cast(command.AndOr, UP_node)
     return loc.Span(node.spids[0])  # first && or ||
+
   if tag == command_e.DoGroup:
     node = cast(command.DoGroup, UP_node)
-    return loc.Span(node.spids[0])  # do spid
+    return node.left  # 'do' token
   if tag == command_e.BraceGroup:
     node = cast(BraceGroup, UP_node)
-    return node.left  # { spid
+    return node.left  # { token
   if tag == command_e.Subshell:
     node = cast(command.Subshell, UP_node)
-    return loc.Span(node.spids[0])  # ( spid
+    return node.left  # ( token
+
   if tag == command_e.WhileUntil:
     node = cast(command.WhileUntil, UP_node)
-    return loc.Span(node.spids[0])  # while spid
+    return node.keyword  # while
   if tag == command_e.If:
     node = cast(command.If, UP_node)
-    return loc.Span(node.arms[0].spids[0])  # if spid is in FIRST arm.
+    return node.if_kw
   if tag == command_e.Case:
     node = cast(command.Case, UP_node)
-    return loc.Span(node.spids[0])  # case keyword spid
+    return node.case_kw
   if tag == command_e.TimeBlock:
     node = cast(command.TimeBlock, UP_node)
-    return loc.Span(node.spids[0])  # time keyword spid
+    return node.keyword
 
   # We never have this case?
   #if node.tag == command_e.CommandList:

frontend/syntax.asdl

@@ -292,7 +292,10 @@ module syntax
   command =
     NoOp
     # Note: do_fork is semantic, not syntactic
-  | Simple(List[word] words, List[Redir] redirects, List[EnvPair] more_env,
+  | Simple(
+           # Token left,
+           List[EnvPair] more_env,
+           List[word] words, List[Redir] redirects,
            ArgList? typed_args, BlockArg? block, bool do_fork)
     # This doesn't technically belong in the LST, but it's convenient for
     # execution

osh/cmd_parse.py

@@ -333,7 +333,7 @@ def _MakeSimpleCommand(
   more_env = []  # type: List[EnvPair]
   _AppendMoreEnv(preparsed_list, more_env)
   # do_fork by default
-  node = command.Simple(words3, redirects, more_env, typed_args, block, True)
+  node = command.Simple(more_env, words3, redirects, typed_args, block, True)
   return node
 
 

tools/osh2oil.py

@@ -621,8 +621,8 @@ def DoCommand(self, node, local_symbols, at_top_level=False):
             self.f.write('for %s in @ARGV ' % node.iter_names[0])
 
             # note: command_t doesn't have .spids
-            self.cursor.SkipUntil(
-              location.GetSpanId(location.OfCommand(node.body)))
+            body_spid = location.GetSpanId(location.OfCommand(node.body))
+            self.cursor.SkipUntil(body_spid)
 
           elif case(for_iter_e.Words):
             iterable = cast(for_iter.Words, UP_iterable)