Initial project import

tools/v/vlib/cli/version.v

@@ -0,0 +1,41 @@
+module cli
+
+fn version_flag(with_abbrev bool) Flag {
+	sabbrev := if with_abbrev { 'v' } else { '' }
+	return Flag{
+		flag:        .bool
+		name:        'version'
+		abbrev:      sabbrev
+		description: 'Print version information'
+	}
+}
+
+fn version_cmd() Command {
+	return Command{
+		name:        'version'
+		description: 'Print version information'
+		execute:     print_version_for_command
+	}
+}
+
+fn print_version_for_command(cmd Command) ! {
+	if cmd.args.len > 0 {
+		for sub_cmd in cmd.commands {
+			if sub_cmd.name == cmd.args[0] {
+				target := unsafe { &sub_cmd }
+				print(target.version())
+				return
+			}
+		}
+		println('Invalid command: ${cmd.args.join(' ')}')
+	} else if cmd.parent != unsafe { nil } {
+		println(cmd.parent.version())
+	} else {
+		println(cmd.version())
+	}
+}
+
+// version returns a generated version `string` for the `Command`.
+pub fn (cmd &Command) version() string {
+	return '${cmd.name} version ${cmd.version}'
+}