expand-range

Generate numeric and alphabetic ranges with steps and zero padding, the way shell brace expansion does. {1..5} becomes 1 2 3 4 5. {a..e} becomes a b c d e. {01..03} keeps the padding and yields 01 02 03. With the regex option it returns one regex source string that matches every value in the range.

Install

[dependencies]
expand-range = "0.1"

Usage

use expand_range::{range, Item};

let r = range(1, 4);
assert_eq!(
    r.as_list(),
    Some(&[Item::Num(1), Item::Num(2), Item::Num(3), Item::Num(4)][..])
);

Letters walk character codes:

use expand_range::{expand, Value, Step, Options};

let r = expand(Value::from("a"), Some(Value::from("c")), Step::None, Options::new());
assert_eq!(
    r.to_string_list(),
    Some(vec!["a".to_string(), "b".to_string(), "c".to_string()])
);

A regex source string instead of a list:

use expand_range::{expand, Value, Step, Options};

let opts = Options::new().to_regex(true);
let r = expand(Value::from(2), Some(Value::from(100)), Step::None, opts);
assert_eq!(r.as_regex(), Some("[2-9]|[1-9][0-9]|100"));

Behavior

• Direction comes from the bounds. expand(5, 1) descends.
• The step magnitude is used. A step of -2 and 2 behave the same.
• A leading zero on any bound or the step pads every output to a common width.
• String bounds keep their text form, so output stays string typed.
• Bounds may be numbers or single characters. Letter ranges walk character codes, so 'a'..'C' passes through ASCII punctuation.
• Invalid input returns an empty list. Set strict_ranges to get a typed error through expand_checked instead.

License

Licensed under the MIT license.