test by api:
$ fkl --help
Feakin is a architecture design and visual collaboration tool. This is the parser for Feakin.
Usage: fkl <COMMAND>
Commands:
dot generate Graphviz/Dot from fkl file
ast generate ast from fkl file
gen generate code from fkl file
run run function from fkl file
help Print this message or the help of the given subcommand(s)
Options:
-h, --help Print help information
-V, --version Print version information