XCX 3.0 I/O and System Commands

Console Output (>!)

The >! operator prints values to stdout, followed by a newline.

>! "Hello";
>! 42;
>! "Path: " + path;

Escape sequences like \n (newline), \t (tab), and \r (carriage return) are supported.

User Input (>?)

The >? operator reads a line from stdin and attempts to parse it into the target variable.

i: age;
>! "Enter age:";
>? age;

Delay (@wait)

Pauses VM execution for a specified number of milliseconds.

@wait 1000; --- Waits for 1 second

@wait is a blocking operation. It does not yield the fiber.

Raw Input (input)

The input module allows reading single keys without waiting for Enter.

Methods

Key Constants

Regular characters are returned directly: "a", "Z", "5", " ".

Example

s: k = input.key(); if (k == “UP”) then; y = y - 1; end;

— wait for specific key s: confirm = input.key() @wait; if (confirm == “q”) then; return; end;

## Terminal Commands (`.terminal`)

Directly interact with the system environment or current process.

| Directive              | Description                                      |
|------------------------|--------------------------------------------------|
| `.terminal !clear`     | Clears the screen                                |
| `.terminal !exit`      | Terminates the VM process                        |
| `.terminal !run s`     | Runs another XCX file in a new process           |
| `.terminal !raw`       | Raw mode — no echo, no buffering                 |
| `.terminal !normal`    | Restores normal terminal mode                    |
| `.terminal !cursor on` | Shows the cursor                                 |
| `.terminal !cursor off`| Hides the cursor                                 |
| `.terminal !move x y`  | Moves the cursor to position `x`, `y` (`i`)      |
| `.terminal !write expr`| Prints `expr` without a trailing newline         |

### Example — Game Loop

```xcx
.terminal !raw;
.terminal !cursor off;
.terminal !clear;

while (true) do;
    s: k = input.key();
    if (k == "ESC") then; break; end;
    if (k == "UP") then; y = y - 1; end;
    .terminal !move x y;
    .terminal !write "@";
    @wait 16;
end;

.terminal !cursor on;
.terminal !normal;

Error Handling and Constraints

• input.key() in normal mode: Returns "" and prints a warning alert.
• @wait on input.ready(): Compilation error.
• .terminal directives: Are not expressions and cannot be assigned to variables.
• .terminal !move: Arguments must be integers (i).
• Terminal Availability: The VM will halt with a fatal error if console handles are redirected or unavailable.