std:io

Standard input/output operations.

Import

import io from "std:io";

Methods

writeln(text: string): void

Write text to stdout with newline:

io.writeln("Hello, World!");
io.writeln(`Count: ${count}`);

write(text: string): void

Write text to stdout without newline:

io.write("Loading");
io.write(".");
io.write(".");
io.writeln("done!");

readLine(): string

Read a line from stdin (blocking):

io.write("Enter name: ");
const name = io.readLine();
io.writeln(`Hello, ${name}!`);

readAll(): string

Read all of stdin until EOF:

const input = io.readAll();
io.writeln(`Read ${input.length} bytes`);

writeErr(text: string): void

Write to stderr without newline:

io.writeErr("Error: ");

writeErrln(text: string): void

Write to stderr with newline:

io.writeErrln("Fatal error occurred");

Examples

Interactive Input

import io from "std:io";

function main(): void {
  io.write("What's your name? ");
  const name = io.readLine();
  
  io.write("How old are you? ");
  const age = io.readLine();
  
  io.writeln(`Hello ${name}, you are ${age} years old!`);
}

Error Output

import io from "std:io";

function processFile(path: string): void {
  if (!fs.exists(path)) {
    io.writeErrln(`Error: file not found: ${path}`);
    return;
  }
  // process file...
}

Pipe Processing

import io from "std:io";

// Read from stdin, process, write to stdout
function main(): void {
  const input = io.readAll();
  const lines = input.split("\n");
  
  for (const line of lines) {
    const processed = line.toUpperCase();
    io.writeln(processed);
  }
}

Run with: echo "hello" | raya run process.raya

Notes

• All I/O operations are blocking
• Use async prefix for concurrent I/O
• stdin/stdout/stderr are buffered
• No formatting - use string interpolation