vab: add --version flag

cli/options.v

@@ -31,6 +31,7 @@ pub:
 	clear_device_log bool @[long: 'log-clear'; xdoc: 'Clear the log buffer on the device before deployment.']
 	// Detected environment
 	dump_usage       bool @[long: 'help'; short: h; xdoc: 'Show this help message and exit']
+	dump_version     bool @[long: 'version'; xdoc: 'Show version information and exit']
 	list_ndks        bool @[xdoc: 'List available NDK versions']
 	list_apis        bool @[xdoc: 'List available API levels']
 	list_build_tools bool @[xdoc: 'List available Build-tools versions']

cli/utils.v

@@ -31,11 +31,14 @@ fn vab_commit_hash() string {
 	return hash.trim_space()
 }
 
-fn version_full() string {
+// version_full returns the version number of this
+// executable *including* a git hash if available.
+pub fn version_full() string {
 	return '${exe_version} ${exe_git_hash}'
 }
 
-fn version() string {
+// version returns the version number found in the nearest `v.mod` file.
+pub fn version() string {
 	mut v := '0.0.0'
 	vmod := @VMOD_FILE
 	if vmod.len > 0 {

vab.v

@@ -55,6 +55,11 @@ fn main() {
 		dump(opt)
 	}
 
+	if opt.dump_version {
+		println('${cli.exe_short_name} ${cli.version_full()}')
+		exit(0)
+	}
+
 	if opt.dump_usage {
 		documentation := flag.to_doc[cli.Options](cli.vab_documentation_config) or {
 			util.vab_error('Could not generate usage documentation via `flag.to_doc[cli.Options](...)` this should not happen',