src/prefix-parser.lisp

   1
   2 (defun fail (arg)
   3   (format nil "What is this \"~A\" of which you speak?~%" arg))
   4
   5 (defgeneric expr-parse (expr))
   6
   7 (defmethod expr-parse ((expr list))
   8   (unless (boundp (car expr))
   9     (throw 'wtfvar (fail (symbol-name (car expr)))))
  10   (loop
  11     :for x :in (cdr expr)
  12     :collect (expr-parse x) :into to-eval
  13     :finally (return (cons (symbol-value (car expr))
  14                            to-eval))))
  15
  16 (defmethod expr-parse ((expr symbol))
  17   (if (boundp expr) (symbol-value expr)
  18     (throw 'wtfvar (fail (symbol-name expr)))))
  19
  20 (defmethod expr-parse ((expr number)) expr)
  21 (defmethod expr-parse ((expr string)) expr)
  22
  23 (defun eval-parsed (s-exprs)
  24   (handler-case
  25     (catch 'over-ex (eval s-exprs))
  26     (error (conditn)
  27            (declare (ignore conditn))
  28            (format nil "Something went wrong during eval, ~
  29                    you probably used a function with bad parameters."))))
  30
  31 (defun process-prefix-from-stream (strm)
  32   (let ((*readtable* (copy-readtable)))
  33     (setf (readtable-case *readtable*) :preserve)
  34     (handler-case
  35       (catch
  36         'wtfvar
  37         (do (expr result)
  38           (nil)
  39           (let ((*package*
  40                   (find-package :lineal.client-vars)))
  41             (setq expr (read strm nil nil)))
  42           (unless expr (return result))
  43           (setq result (eval-parsed (expr-parse expr)))))
  44       (error (conditn)
  45              (declare (ignore conditn))
  46              "You probably forgot to add a closing parenthesis."))))
  47