src/code/parse-body.lisp

   1 ;;;; functions used to parse function/macro bodies
   2 ;;;;
   3 ;;;; FIXME: In an early attempt to bootstrap SBCL, this file
   4 ;;;; was loaded before fundamental things like DEFUN and AND and OR
   5 ;;;; were defined, and it still bears scars from the attempt to
   6 ;;;; make that work. (TAGBODY, forsooth..) It should be cleaned up.
   7
   8 ;;;; This software is part of the SBCL system. See the README file for
   9 ;;;; more information.
  10 ;;;;
  11 ;;;; This software is derived from the CMU CL system, which was
  12 ;;;; written at Carnegie Mellon University and released into the
  13 ;;;; public domain. The software is in the public domain and is
  14 ;;;; provided with absolutely no warranty. See the COPYING and CREDITS
  15 ;;;; files for more information.
  16
  17 (in-package "SB!INT")
  18
  19 (/show0 "entering parse-body.lisp")
  20
  21 ;;; Given a sequence of declarations (and possibly a documentation
  22 ;;; string) followed by other forms (as occurs in the bodies of DEFUN,
  23 ;;; DEFMACRO, etc.) return (VALUES FORMS DECLS DOC), where DECLS holds
  24 ;;; declarations, DOC holds a doc string (or NIL if none), and FORMS
  25 ;;; holds the other forms.
  26 ;;;
  27 ;;; If DOC-STRING-ALLOWED is NIL, then no forms will be treated as
  28 ;;; documentation strings.
  29 (defun parse-body (body &optional (doc-string-allowed t))
  30   (let ((reversed-decls nil)
  31         (forms body)
  32         (doc nil))
  33     ;; Since we don't have macros like AND, OR, and NOT yet, it's
  34     ;; hard to express these tests clearly. Giving them names
  35     ;; seems to help a little bit.
  36     (flet ((doc-string-p (x remaining-forms)
  37              (if (stringp x)
  38                (if doc-string-allowed
  39                  ;; ANSI 3.4.11 explicitly requires that a doc
  40                  ;; string be followed by another form (either an
  41                  ;; ordinary form or a declaration). Hence:
  42                  (if remaining-forms
  43                    (if doc
  44                      ;; ANSI 3.4.11 says that the consequences of
  45                      ;; duplicate doc strings are unspecified.
  46                      ;; That's probably not something the
  47                      ;; programmer intends. We raise an error so
  48                      ;; that this won't pass unnoticed.
  49                      (error "duplicate doc string ~S" x)
  50                      t)))))
  51            (declaration-p (x)
  52              (if (consp x)
  53                (eq (car x) 'declare))))
  54       (tagbody
  55         :again
  56         (if forms
  57           (let ((form1 (first forms)))
  58             ;; Note: The (IF (IF ..) ..) stuff is because we don't
  59             ;; have the macro AND yet.:-|
  60             (if (doc-string-p form1 (rest forms))
  61               (setq doc form1)
  62               (if (declaration-p form1)
  63                 (setq reversed-decls
  64                       (cons form1 reversed-decls))
  65                 (go :done)))
  66             (setq forms (rest forms))
  67             (go :again)))
  68         :done)
  69       (values forms
  70               (nreverse reversed-decls)
  71               doc))))
  72
  73 (/show0 "leaving parse-body.lisp")