clap is the command line argument parsing library. I especially like it because it lets me declare a struct, with strong Rust typing, to define what the command line should work like. I also like that meshes well with the tradition of Unix command line interfaces.
I've implemented command line parsing in C, shell, Python, and more. For a while the Python standard library had my implementation of getopt_long. clap is the only library for this that I actually enjoy using.
serde and the small ecosystem around it make it painless to serialize and deserialize structured data. I define a Rust type, annotate it with serde, and use serde-foo library to read and write files in format foo. I mostly use serde-json (for JSON) and serde-norway (for YAML) as those are the formats I mostly need.
@liw no way. no way the serde library for yaml is called norway.
for context, the "norway problem":
country_codes:
GB
FR
CH
NO
when loaded becomes ['GB', 'FR', 'CH', false]
