restruct is used to interpret binary data stored in files or other sources or convert between C structs and Rust types and when using a parser-generator is considered disproportionate. It is a brainchild of Python's struct-module.

The library uses Format Strings as compact descriptions of the binary data and the intended conversion to/from Rust-types. The Format Strings are interpreted at compile-time to generate a type whose functions can be used to convert between unstructured and structured data.

```rust // Generate a parser in little-endian for two 32bit integers, a float and a bool.

[derive(restruct_derive::Struct)]

[fmt="<2if?"]

struct FooParser;

// Pack a tuple of two integers, a float and a bool into a [u8; ]-buffer. let packed = FooParser::pack((1, 2, 3.0, false)); asserteq!(packed, [1, 0, 0, 0, 2, 0, 0, 0, 0, 0, 64, 64, 0]); assert_eq!(packed.len(), FooParser::SIZE);

// Packing and unpacking can't fail at runtime. let unpacked = FooParser::unpack(packed); assert_eq!(unpacked, (1, 2, 3.0, false));

// Any io::Read can be used directly. let unpacked = FooParser::readfrom(&mut &packed[..]).expect("i/o failed"); asserteq!(unpacked, (1, 2, 3.0, false));

// Any io::Write can be used directly. let mut buffer = Vec::withcapacity(FooParser::SIZE); FooParser::writeto((1, 2, 3.0, false), &mut buffer).expect("i/o failed"); assert_eq!(&buffer, &packed); ```

rust,ignore // Because packing and unpacking is const we can use these functions to initialize other consts const TEAPOT: <Tea as restruct::Struct>::Unpacked = Tea::unpack(*include_bytes!("teapot.bin")); const TEAPOT_TEMPERATURE: i32 = TEAPOT.0; const TEAPOT_FILL_STATUS: f32 = TEAPOT.2; const TEAPOT_ACTIVE: bool = TEAPOT.3;