Struct IoContext 

pub struct IoContext { /* private fields */ }

File descriptor table for the REPL session.

Lives in the binary layer and is passed into eval_with_io. File descriptors 1 (stdout) and 2 (stderr) are virtual — not stored here, handled by write_to_fd directly. User-opened files start at fd 3.

Implementations

impl IoContext

pub fn new() -> Self

Creates an empty I/O context with no open file handles.

pub fn fopen(&mut self, path: &str, mode: &str) -> i32

Opens a file and returns a new file descriptor, or -1 on failure. Supported modes: "r", "w", "a", "r+".

pub fn fclose(&mut self, fd: i32) -> i32

Closes a file descriptor. Returns 0 on success, -1 if fd is unknown.

pub fn fclose_all(&mut self)

Closes all open file handles.

pub fn fgetl(&mut self, fd: i32) -> Option<String>

Reads one line from fd, stripping the trailing newline (fgetl semantics). Returns None at EOF or on error.

pub fn fgets(&mut self, fd: i32) -> Option<String>

Reads one line from fd, keeping the trailing newline (fgets semantics). Returns None at EOF or on error.

pub fn write_to_fd(&mut self, fd: i32, s: &str) -> Result<(), String>

Writes a string to a file descriptor. fd 1 = stdout, fd 2 = stderr; all others must be in the handle table.

Trait Implementations

impl Default for IoContext

fn default() -> Self

Returns the “default value” for a type.