[builtin/complete] Stub for complete -C

So we can source testdata/completion/quoting.bash

Now we can see our extra quoting.

core/completion.py

@@ -528,6 +528,19 @@ def Matches(self, comp):
                     yield path
 
 
+class CommandAction(CompletionAction):
+
+    def __init__(self, cmd_ev, command_name):
+        # type: (CommandEvaluator, str) -> None
+        self.cmd_ev = cmd_ev
+        self.command_name = command_name
+
+    def Matches(self, comp):
+        # type: (Api) -> Iterator[str]
+        for candidate in ['TODO-complete-C']:
+            yield candidate
+
+
 class ShellFuncAction(CompletionAction):
     """Call a user-defined function using bash's completion protocol."""
 

frontend/flag_def.py

@@ -259,6 +259,9 @@ def _DefineCompletionFlags(spec):
     # type: (_FlagSpecAndMore) -> None
     spec.ShortFlag('-F', args.String, help='Complete with this function')
     spec.ShortFlag('-W', args.String, help='Complete with these words')
+    spec.ShortFlag('-C', args.String,
+                   help='Complete with stdout lines of this command')
+
     spec.ShortFlag(
         '-P',
         args.String,
@@ -339,6 +342,7 @@ def _DefineCompletionActions(spec):
 COMPLETE_SPEC.ShortFlag('-E', help='Define the compspec for an empty line')
 COMPLETE_SPEC.ShortFlag(
     '-D', help='Define the compspec that applies when nothing else matches')
+
 # I would like this to be less compatible
 # Field name conflicts with 'print' keyword
 #COMPLETE_SPEC.LongFlag(

osh/builtin_comp.py

@@ -15,7 +15,7 @@
 from core import vm
 from data_lang import qsn
 from mycpp import mylib
-from mycpp.mylib import log
+from mycpp.mylib import log, print_stderr
 from frontend import flag_spec
 from frontend import args
 from frontend import consts
@@ -125,7 +125,11 @@ def __init__(
 
     def Build(self, argv, attrs, base_opts):
         # type: (List[str], _Attributes, Dict[str, bool]) -> UserSpec
-        """Given flags to complete/compgen, return a UserSpec."""
+        """Given flags to complete/compgen, return a UserSpec.
+
+        Args:
+          argv: only used for error message
+        """
         cmd_ev = self.cmd_ev
 
         # arg_types.compgen is a subset of arg_types.complete (the two users of this
@@ -139,11 +143,18 @@ def Build(self, argv, attrs, base_opts):
             func_name = arg.F
             func = cmd_ev.procs.get(func_name)
             if func is None:
-                raise error.Usage('Function %r not found' % func_name,
+                raise error.Usage('function %r not found' % func_name,
                                   loc.Missing)
             actions.append(
                 completion.ShellFuncAction(cmd_ev, func, self.comp_lookup))
 
+        if arg.C is not None:
+            # this can be a shell FUNCTION too, not just an external command
+            # Honestly seems better than -F?  Does it also get COMP_CWORD?
+            command = arg.C
+            actions.append(completion.CommandAction(cmd_ev, command))
+            print_stderr('osh warning: complete -C not implemented')
+
         # NOTE: We need completion for -A action itself!!!  bash seems to have it.
         for name in attrs.actions:
             if name == 'alias':
@@ -359,11 +370,12 @@ def Run(self, cmd_val):
             # error printed above
             return 2
 
-        # NOTE: Matching bash in passing dummy values for COMP_WORDS and COMP_CWORD,
-        # and also showing ALL COMPREPLY reuslts, not just the ones that start with
-        # the word to complete.
+        # NOTE: Matching bash in passing dummy values for COMP_WORDS and
+        # COMP_CWORD, and also showing ALL COMPREPLY results, not just the ones
+        # that start
+        # with the word to complete.
         matched = False
-        comp = completion.Api('', 0, 0)
+        comp = completion.Api('', 0, 0)  # empty string
         comp.Update('compgen', to_complete, '', -1, None)
         try:
             for m, _ in user_spec.Matches(comp):
@@ -516,7 +528,7 @@ def Run(self, cmd_val):
         begin = 0 if arg.begin == -1 else arg.begin
         end = len(arg.c) if arg.end == -1 else arg.end
 
-        log('%r begin %d end %d', arg.c, begin, end)
+        #log('%r begin %d end %d', arg.c, begin, end)
 
         # Copied from completion.ReadlineCallback
         comp = completion.Api(line=arg.c, begin=begin, end=end)

spec/builtin-completion.test.sh

@@ -1,5 +1,5 @@
 
-## oils_failures_allowed: 2
+## oils_failures_allowed: 3
 ## compare_shells: bash
 
 #### complete with no args and complete -p both print completion spec
@@ -455,3 +455,30 @@ compgen -A builtin g
 ## STDOUT:
 getopts
 ## END
+
+#### complete -C vs. compgen -C
+
+f() { echo foo; echo bar; }
+
+# Bash prints warnings: -C option may not work as you expect
+#                       -F option may not work as you expect
+#
+# https://unix.stackexchange.com/questions/117987/compgen-warning-c-option-not-working-as-i-expected
+#
+# compexport fixes this problem, because it invokves ShellFuncAction, whcih
+# sets COMP_ARGV, COMP_WORDS, etc.
+#
+# Should we print a warning?
+
+compgen -C f b
+echo compgen=$?
+
+complete -C f b
+echo complete=$?
+
+## STDOUT:
+foo
+bar
+compgen=0
+complete=0
+## END