jwutils.Cmd: Add method add_subcommands()

Add method jwutils.Cmd.add_subcommands(). cmd.add_subcommands(C) will
parse and invoke C as a subcommand of cmd, if C is of type jwutils.cmd.

Signed-off-by: Jan Lindemann <jan@janware.com>

tools/python/jwutils/Cmd.py

@@ -1,9 +1,14 @@
 import abc
 import argparse
 
+from jwutils import log
+
 # compatible with Python 2 *and* 3
 ABC = abc.ABCMeta('ABC', (object,), {'__slots__': ()})
 
+# full blown example of one level of nested subcommands
+# git -C project remote -v show -n myremote
+
 class Cmd(ABC): # export
 
     @abc.abstractmethod
@@ -13,6 +18,9 @@ class Cmd(ABC): # export
     def __init__(self, name, help):
         self.name = name
         self.help = help
+        self.parent = None
+        self.children = []
+        self.child_classes = []
 
     async def _run(self, args):
         pass
@@ -23,3 +31,12 @@ class Cmd(ABC): # export
         r.set_defaults(func=self.run)
         return r
 
+    def add_subcommands(self, cmd):
+        if isinstance(cmd, list):
+            for c in cmd:
+                self.add_subcommands(c)
+                return
+        self.child_classes.append(cmd)
+
+    def add_arguments(self, parser):
+        pass

tools/python/jwutils/Cmds.py

@@ -6,15 +6,27 @@ import inspect
 import re
 import pickle
 import asyncio
+
 import jwutils
 from jwutils import log
 
 class Cmds: # export
 
+    def __add_cmd_to_parser(self, cmd, parsers):
+        parser = cmd.add_parser(parsers)
+        cmd.add_arguments(parser)
+        if len(cmd.child_classes) > len(cmd.children):
+            for c in cmd.child_classes:
+                cmd.children.append(c())
+        for sub_cmd in cmd.children:
+            subparsers = parser.add_subparsers(title='Available commands of ' + cmd.name, metavar='')
+            self.__add_cmd_to_parser(sub_cmd, subparsers)
+
     def __init__(self, description = '', filter = '^Cmd.*', modules=None, eloop=None):
         self.__description = description
         self.__filter = filter
         self.__modules = modules
+        self.__cmds = []
         default_log_level = log.NOTICE
         default_log_flags = 'stderr,position,prio,color'
         # poor man's parsing in the absence of a complete command-line definition
@@ -40,9 +52,9 @@ class Cmds: # export
         if eloop is None:
             self.eloop = asyncio.get_event_loop()
             self.__own_eloop = True
-        subparsers = self.__parser.add_subparsers(title='Available commands', metavar='')
         if self.__modules == None:
             self.__modules = [ '__main__' ]
+        subcmds = set()
         for m in self.__modules:
             if m != '__main__':
                 importlib.import_module(m)
@@ -54,7 +66,16 @@ class Cmds: # export
                 log.slog(log.DEBUG, 'instantiating command "{}"'.format(c))
                 cmd = c()
                 cmd.cmds = self
-                cmd.add_parser(subparsers)
+                #cmd.add_parser(subparsers)
+                self.__cmds.append(cmd)
+                for child in cmd.child_classes:
+                    subcmds.add(child)
+                subcmds.update(cmd.child_classes)
+
+        cmds = [cmd for cmd in self.__cmds if type(cmd) not in subcmds]
+        subparsers = self.__parser.add_subparsers(title='Available commands', metavar='')
+        for cmd in cmds:
+            self.__add_cmd_to_parser(cmd, subparsers)
 
     async def __run(self):
         args = self.__parser.parse_args()
@@ -69,7 +90,7 @@ class Cmds: # export
                 self.eloop = None
             self.__own_eloop = False
 
-    def parser():
+    def parser(self):
         return self.__parser
 
     def run(self):