transduce: Zero-Copy Isomorphic Parsing

Your code should look like what it parses.

See this example from lib.rs: rust let parser = exact(&b'(') >> verbatim() << exact(&b')'); let input = b"(*)"; assert_eq!( parser.parse(input), Ok(&b'*'), // Reference to the region of input inside parentheses ); // Or, equivalently: assert_eq!( parenthesized(verbatim).parse(input), Ok(&b'*'), ); This does exactly what it looks like it does.

Equivalently, rust assert_eq!(parenthesized(verbatim()).parse(rawstr.chars()), Ok('*'))

Pretty-printed errors

The parse method automatically locates the error (even for user-defined parsers) and prints out gorgeous, colored Rust-style errors: rust (exact(b'?') >> exact(b'?')).parse_or_panic(b"???"); ...| Error while parsing: 1 | ??? | ^ Unparsed input remains after parsing what should have been everything   rust (verbatim() & verbatim() & verbatim() & verbatim()).parse_or_panic(b"???"); ...| Error while parsing: 1 | ??? | ^ Reached end of input but expected an item   rust (verbatim() << exact(b'!')).parse_or_panic(b"???") ...| Error while parsing: 1 | ??? | ^ Expected 33 but found 63

Thanks

Huge shoutout to UPenn's CIS 194 and Haskell's higher-order parsing libraries I learned in 194.

Future improvements

Removing boxed closures once this feature is stabilized. Already works with the feature-gate enabled: just enable the nightly feature on this crate. I haven't benchmarked yet, but when the name of a type fills almost the entire screen and encodes a needless abstraction with runtime cost, it's gotta go on moral principle.