Using the Rust Toolchain

Last updated 3 months ago

Input and output

Valida programs can interact with the environment using the input and output tapes. In the Valida zk-VM, the input tape is mapped to stdin, or the input file specified on the command line. The output tape is mapped to stdout, and the output file specified on the command line for valida run.

The printlnmacro is known to work. The following methods are known to work on stdin: read, read_line, read_until, lines, read_to_string, and read_to_end. There may be some issues with signaling end of input via ctrl+D on the command line. Sometimes it may have to be signaled more than once. This is a known issue as of release 0.7.0-alpha.

The Rust toolchain provides functions for line-based interaction with the input and output tapes:

valida_rs::io::read_line<T>() -> Result<T, Box<dyn Error>>

Reads a line from the input tape and returns the result
T: std::str::FromStr
<T as std::str::FromStr>::Err: std::error::Error + 'static

valida_rs::io::read() -> Result<Vec<u8>, Box<dyn Error>>: reads all of the input from the input tape and returns it

valida_rs::io::read_until(stop_char: u8) -> Result<Vec<u8>, Box<dyn Error>>: reads from the input tape until reaching the end of input or stop_char

valida_rs::io::read_n(n: usize) -> Result<Vec<u8>, Box<dyn Error>>: reads n many bytes from the input tape

valida_rs::io::write_vec(v: impl AsRef<[u8]>) -> Result<(), Box<dyn Error>>: writes the contents of v to the output tape

valida_rs::io::read_and_deserialize<T: DeserializeOwned>() -> Result<T, Box<dyn Error>>: reads and deserializes an object from the input tape

valida_rs::io::write<T: Serialize>(value: &T) -> Result<(), Box<dyn Error>>: serializes and writes value to the output tape

Pseudo-random numbers

The Rust toolchain provides the following function for generating pseudo-random numbers:

valida_rand(s: &mut [u8]) - > Result<(), getrandom::Error>: populates s with pseudo-randomly generated bytes

Note that currently this function uses a static seed and thus behaves deterministically, producing the same result on each run of a program.

Input and output

The Rust toolchain provides functions for line-based interaction with the input and output tapes:

valida_rs::io::read_line<T>() -> Result<T, Box<dyn Error>>

Reads a line from the input tape and returns the result
T: std::str::FromStr
<T as std::str::FromStr>::Err: std::error::Error + 'static

valida_rs::io::read() -> Result<Vec<u8>, Box<dyn Error>>: reads all of the input from the input tape and returns it

valida_rs::io::read_until(stop_char: u8) -> Result<Vec<u8>, Box<dyn Error>>: reads from the input tape until reaching the end of input or stop_char

valida_rs::io::read_n(n: usize) -> Result<Vec<u8>, Box<dyn Error>>: reads n many bytes from the input tape

valida_rs::io::write_vec(v: impl AsRef<[u8]>) -> Result<(), Box<dyn Error>>: writes the contents of v to the output tape

valida_rs::io::read_and_deserialize<T: DeserializeOwned>() -> Result<T, Box<dyn Error>>: reads and deserializes an object from the input tape

valida_rs::io::write<T: Serialize>(value: &T) -> Result<(), Box<dyn Error>>: serializes and writes value to the output tape

Pseudo-random numbers

The Rust toolchain provides the following function for generating pseudo-random numbers:

valida_rand(s: &mut [u8]) - > Result<(), getrandom::Error>: populates s with pseudo-randomly generated bytes

Note that currently this function uses a static seed and thus behaves deterministically, producing the same result on each run of a program.