# `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"???");
```
```
| ^ 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](https://github.com/rust-lang/rust/issues/63063) 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_.