%ifndef MONAD_INC
%define MONAD_INC
%ifndef ALLOC_INC
%include "alloc.inc"
%endif

struc Monad
just:	resq 1
exist:	resb 1
endstruc

%macro m_make 1-3	0,0
	;; %1 = Name
	;; %2 = Address of Structure
	;; %3 = Something > 0, Nothing = 0
m_%1:
	istruc Monad
	at just, dq %2 ; The address of the Monad-wrapped structure
	at exist, db %3		  ; Something > 0, Nothing = 0
	iend
%endm

%macro m_Just 1-3	0,0
	;; %1 = Name
	;; %2 = New Structure Address
	;; %3 = Something > 0, Nothing = 0
	%if %2 != 0
	lea	rax,	[rel %2]
	mov	qword [%1+just],	rax
	%else
	mov	qword [%1+just],	0
	%endif
	%if %3 != 0
	mov	byte [%1+exist],	%3
	%else
	mov	byte [%1+exist],	0
	%endif
	lea	rax,	[%1]
%endm

%macro m_Nothing 1
	;; %1 = Name
	m_Just %1
%endm

%macro m_return 1-2	rax
	m_Just	%1, %2, 1
%endm
	
%macro m_bind 1-2	rax
	;; %1 = Callable Function with Single Argument, the Unwrapped Monad
	;; %2 = Monad
	;; m a -> (a -> m b) -> m b
	lea	rax,	[%2]
	mov	rcx,	rax
	mov	al,	byte [rcx + exist]
	cmp	al,	0
	je	%%exit
	mov	rax,	[rcx + just]
	call	%1
%%exit:
%endmacro
	
%macro m_call 1-2	rax
	;; %1 = Callable Function with Single Argument, the Unwrapped Monad
	;; %2 = Monad
	;; m a -> (a -> !) -> !
	lea	rax,	[%2]
	mov	rcx,	rax
	mov	al,	byte [rcx + exist]
	cmp	al,	0
	je	%%exit
	mov	rax,	[rcx + just]
	call	%1
%%exit:
%endmacro

%macro alloc_m 0
	alloc	Monad_size
%endm

%macro free_m 1
	free	%1,	Monad_size
%endm

%endif