Clean up argument parsing with match
Clean up argument parsing with match

kevinmehall/rust-peg,tempbottle/rust-peg,jsgf/rust-peg,daramos/rust-peg,kevinmehall/rust-peg,jsgf/rust-peg,a-wortman/rust-peg,tempbottle/rust-peg,a-wortman/rust-peg,loganmhb/rust-peg,daramos/rust-peg,loganmhb/rust-peg