Operations & Functions (op)

In AzLang’s real SDK syntax, callable procedures and functions are declared using the op keyword. This aligns with AzLang’s low-level systems nature: procedures are atomic machine operations.

1. Declaring Internal Operations

An operation defines parameters, parameter types, a return type, and an indented block:

op add(const int a, const int b): int
    return a + b

op multiply(var int x, const int factor): int
    return x * factor

Mutability in Parameters

• const <Type> <name>: Value parameter passed immutably.
• var <Type> <name>: Parameter treated as a mutable pointer reference.

2. Returning Void

When an operation does not yield a value (e.g. system exit or logging), its return type is specified as void:

op log_message(const str msg, const int len): void
    write(Stdout, msg, len)

3. External Operations (@link + op)

To declare an interface to an external assembly source, place the @link directive above the op signature:

@link("./sdk/src/write.s")
op write(FD fd, const str val, const int size): void

@link("./sdk/src/exit.s")
op exit(const int val): void

@link("./sdk/src/fopen.s")
op fopen(const str val, FLAG flag, FMODE mode): File

When AzLang compiles this file, it registers the external function signature in its symbol table and, for every operation that is actually called, emits an include directive pulling the assembly source into the generated .asm — fasm then resolves the symbol statically in the same pass.