`cargo run --example repl`
`1 2 3`
`arg1 arg2 arg3`
`kw: 1`
`keywordarg: True`
`-flag1 -flag2`
`kw: "string with spaces`
`positional argument with spaces`
`range: 1..10`
`1..10`
`..10`
`ids: -10..20`
`vals: ["val1", "val2"]`
`vals: [1, 2, 3]`
`[1,2,3]`