bexpand

Bash-style brace expansion in Rust.

This does not 100% conform to Bash's style in the following ways:

• There are patterns considered ill-formed and will throw an error in bexpand. It will not try to truck along if a bad pattern is found.
• Braces are special characters and are not allowed without either being correctly formed or being escaped. In Bash a{b,c}d}e expands to abd}e acd}e and a{b{c,d}e expands to a{bce a{bde. In bexpand, both are errors.
• Empty and single-component lists are considered acceptable in bexpand. In Bash, a{}b and a{b}c are both literally repeated by the shell. In bexpand, these expand to ab and abc.
• bexpand allows character sequences to iterate any valid unicode codepoints. {🥰..🥴..2} is a valid character sequence, as is {\{..\.}, and {9..A}. Technically, {\0..\9} is valid as well, and will be treated as a character sequence, though it expands to the exact same thing as a numeric sequence of the same form. Anything that would generate an illegal unicode codepoint will generate an error.
• The width specifier is done with an equal sign at the beginning of the opening brace instead, so in Bash, {001..100} is instead done in bexpand as {=1..100}. This is to allow things like {=-5..10}, which is impossible to express in Bash.

License

Copyright 2023 Taylor Richberger

Published under the terms of the Mozilla Public License Version 2.0.