Mac

Used to express macro types, or to define macros.

mac argCnt<integer> -> type

Expresses a macro type of given number of arguments.

argCnt must not be negative.

    sym m0:(mac 2);

::variadic on the list of argument types expresses a variadic macro.

mac name<id> ([argName<id>...]) body<block> -> macro

Defines a macro under the given name. Returns that macro.

There must not be a function, special form, type, or global symbol with the same. The name must not be one of cn, *, or [].

It is allowed to overload macros of the same name. There must not be conflicting function definitions among them.

There must not be multiple arguments of the same name.

When executing, the macro will execute the list of instructions in body under a new scope. This is always done through evaluation. Macros are expected to return a value after they finish execution.

mac square (x::preprocess) {
    ret \(* ,x ,x);
};

::global must be placed on mac if this instruction is not executed in the global scope.

::preprocess on argName makes the argument not be escaped before processing on invocation.

::plusEscape on argName makes the argument be escaped an additional time before processing on invocation.

Arguments must not be marked both to not be escaped and to be escaped an additional time.

::variadic on the last argument name makes this a variadic macro. On invocation, all surplus arguments will be grouped as elements of a raw value that will be passed as the value of the variadic argument.