threading.lisp

(defmacro -> (expr-1 expr-2 &rest exprs)                       
  (let ((expr-2-with-expr-1-let `(let ((<- ,expr-1)) ,expr-2)))
    (if exprs                                                  
        `(-> ,expr-2-with-expr-1-let ,@exprs)                  
        expr-2-with-expr-1-let ) ) )                           
                                                               
(-> (load-data)                                                
    (group-by-species <-)                                      
    (gethash 'iris-virginica <-)                               
    (format t "~a~%" <-) )