jw.pkg.cmds.distro.CmdInfo: Add class

CmdInfo provides what "projects os-cascade" provided as "distro info
--format '%{cascade}'" plus additional macros: %{id}, %{name},
%{codename} and ${gnu-triplet}.

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

src/python/jw/pkg/cmds/distro/CmdInfo.py

@@ -0,0 +1,36 @@
+# -*- coding: utf-8 -*-
+
+import re
+from argparse import Namespace, ArgumentParser
+
+from ..Cmd import Cmd
+from ..CmdProjects import CmdProjects
+
+class CmdInfo(Cmd): # export
+
+    def __init__(self, parent: CmdProjects) -> None:
+        super().__init__(parent, 'info', help='Print information about operating system this script runs on')
+
+    def _expand_macros(self, string: str) -> str:
+        ret = string
+        for macro in re.findall("%{([A-Za-z_-]+)}", string):
+            try:
+                name = 'distro_' + macro.replace('-', '_')
+                val = getattr(self.app, name)
+                patt = r'%{' + macro + r'}'
+                if ret.find(patt) == -1:
+                    continue
+                ret = ret.replace(patt, val)
+            except Exception as e:
+                raise Exception(f'Failed to expand macro "{macro}" inside "{string}": {e}')
+        return ret
+
+    def add_arguments(self, parser: ArgumentParser) -> None:
+        super().add_arguments(parser)
+        macro_names = ', '.join(['%%{' + name.replace('distro_', '').replace('_', '-') + '}'
+                                 for name in dir(self.app) if name.startswith('distro_')])
+        parser.add_argument('--format', default='%{cascade}',
+                            help=f'Format string, expanding macros {macro_names}')
+
+    async def _run(self, args: Namespace) -> None:
+        print(self._expand_macros(args.format))