(define-module (control monad)
  #:use-module (control monad procedures)
  ;; #:use-module (control monad syntax)
  #:export (do <-)
  ;; #:re-export (>>= do <-)
                )

(define-syntax do
  (syntax-rules (<- let =)
    ((_ let var = val rest ...)
     (let ((var val)) (do rest ...)))
    ((_ ptrn <- val rest ...)
     (<- ptrn val rest ...))
    ((_ a) a)
    ((_ token rest ...)
     (begin token (do rest ...)))))

(define-syntax <-
  (syntax-rules (just writer)
    ((_ (just var) val rest ...)
     (>>= val (lambda (var) rest ...)))
    ((_ (writer var) val rest ...)
     (>>= val (lambda (var) rest ...))))
  
  
  #;
  (lambda (x)
    (syntax-case x (just writer)
      ((_ (just var) val rest ...)
       #'(>>= val (lambda (var) rest ...)))
      ((_ (writer var) val rest ...)
       #'(>>= val (lambda (var) rest ...)))
      #; 
      ((_ (left var) val rest ...)      ;
      #'(>>= val (lambda (var) rest ...)))
      #; 
      ((_ (right var) val rest ...)     ;
      #'(>>= val (lambda (var) rest ...))))))