bad-anaphoric-macro.lisp

; ----- package a ----- ;
(defpackage pack-a
  (:use :cl))
(in-package :pack-a)

; 文字列strをinternしてvalueを束縛する
(defmacro with-interned-str (str value &body body)
  (let ((sym (intern (string-upcase str))))
    `(let ((,sym ,value))
       ,@body)))

(with-interned-str "abc" 100
  (print abc))
; => 100

; ----- package b ----- ;
(defpackage pack-b
  (:use :cl))
(in-package :pack-b)

(defmacro some-macro (value)
  `(pack-a::with-interned-str "def" ,value
     (print def)))

(some-macro 200)
; => 200

; ----- package c ----- ;
(defpackage pack-c
  (:use :cl))
(in-package :pack-c)

(pack-b::some-macro 300)
; Error => The variable PACK-B::DEF is unbound.