;;;; From CMULISP

;;;; From defmacro.lisp

;;;; Some variable definitions.

;;; Variables for amassing the results of parsing a defmacro.  Declarations
;;; in DEFMACRO are the reason this isn't as easy as it sounds.
;;;

(in-package :si)

(defvar *arg-tests* ()
  "A list of tests that do argument counting at expansion time.")

(defvar *system-lets* nil)
;(defvar *system-lets* ()
;  "Let bindings that are done to make lambda-list parsing possible.")

(defvar *user-lets* ()
  "Let bindings that the user has explicitly supplied.")

(defvar *default-default* nil
  "Unsupplied optional and keyword arguments get this value defaultly.")

;; Temps that we introduce and might not reference.
(defvar *ignorable-vars*)

;;;; Stuff to parse DEFMACRO, MACROLET, DEFINE-SETF-METHOD, and DEFTYPE.

;;; We save space in macro definitions by callig this function.
;;;
(defun do-arg-count-error (error-kind name arg lambda-list minimum maximum)
  (error "Error in do-arg-count-error: ~S ~S ~S ~S ~S ~S~%"
	 error-kind
	 name
	 arg
	 lambda-list
	 minimum
	 maximum))

;;; PARSE-DEFMACRO returns, as multiple-values, a body, possibly a declare
;;; form to put where this code is inserted, and the documentation for the
;;; parsed body.
;;;
(defun parse-defmacro (lambda-list arg-list-name code name error-kind
				   &key (annonymousp nil)
				   (doc-string-allowed t)
				   ((:environment env-arg-name))
				   ((:default-default *default-default*))
				   (error-fun 'error))
  "Returns as multiple-values a parsed body, any local-declarations that
   should be made where this body is inserted, and a doc-string if there is
   one."
  (multiple-value-bind (body declarations documentation)
		       (parse-body code nil doc-string-allowed)
    (let* ((*arg-tests* ())
	   (*user-lets* ())
	   (*system-lets* ())
	   (*ignorable-vars* ()))
      (multiple-value-bind
	  (env-arg-used minimum maximum)
	  (parse-defmacro-lambda-list lambda-list arg-list-name name
				      error-kind error-fun (not annonymousp)
				      nil env-arg-name)
	(values
	 `(let* ,(nreverse *system-lets*)
	   ,@(when *ignorable-vars*
	       `((declare (ignorable ,@*ignorable-vars*))))
	    ,@*arg-tests*
	    (let* ,(nreverse *user-lets*)
	      ,@declarations
	      ,@body))
	 `(,@(when (and env-arg-name (not env-arg-used))
	       `((declare (ignore ,env-arg-name)))))
	 documentation
	 minimum
	 maximum)))))

(defun make-keyword (symbol)
  "Takes a non-keyword symbol, symbol, and returns the corresponding keyword."
  (intern (symbol-name symbol) (find-package "KEYWORD")))

(defun verify-keywords (key-list valid-keys allow-other-keys)
  (do ((already-processed nil)
       (unknown-keyword nil)
       (remaining key-list (cddr remaining)))
      ((null remaining)
       (if (and unknown-keyword
		(not allow-other-keys)
		(not (lookup-keyword :allow-other-keys key-list)))
	   (values :unknown-keyword (list unknown-keyword valid-keys))
	   (values nil nil)))
    (cond ((not (and (consp remaining) (listp (cdr remaining))))
	   (return (values :dotted-list key-list)))
	  ((null (cdr remaining))
	   (return (values :odd-length key-list)))
	  #+nil ;; Not ANSI compliant to disallow duplicate keywords.
	  ((member (car remaining) already-processed)
	   (return (values :duplicate (car remaining))))
	  ((or (eq (car remaining) :allow-other-keys)
	       (member (car remaining) valid-keys))
	   (push (car remaining) already-processed))
	  (t
	   (setf unknown-keyword (car remaining))))))

(defun lookup-keyword (keyword key-list)
  (do ((remaining key-list (cddr remaining)))
      ((endp remaining))
    (when (eq keyword (car remaining))
      (return (cadr remaining)))))
;;;
(defun keyword-supplied-p (keyword key-list)
  (do ((remaining key-list (cddr remaining)))
      ((endp remaining))
    (when (eq keyword (car remaining))
      (return t))))



;(defun make-keyword (a) 
;	(error "Need to write make-keyword ~S" a))

;(defun defmacro-error (a b c) 
;	(error "Need to write defmacro-error ~S ~S ~S" a b c))

(defun parse-defmacro-lambda-list
       (lambda-list arg-list-name name error-kind error-fun
		    &optional top-level env-illegal env-arg-name)
  (let ((path (if top-level `(cdr ,arg-list-name) arg-list-name))
	(now-processing :required)
	(maximum 0)
	(minimum 0)
	(keys ())
	rest-name restp allow-other-keys-p env-arg-used)
    ;; This really strange way to test for '&whole is neccessary because member
    ;; does not have to work on dotted lists, and dotted lists are legal
    ;; in lambda-lists.
    (when (and (do ((list lambda-list (cdr list)))
		   ((atom list) nil)
		 (when (eq (car list) '&whole) (return t)))
	       (not (eq (car lambda-list) '&whole)))
      (error "&Whole must appear first in ~S lambda-list." error-kind))
    (do ((rest-of-args lambda-list (cdr rest-of-args)))
	((atom rest-of-args)
	 (cond ((null rest-of-args) nil)
	       ;; Varlist is dotted, treat as &rest arg and exit.
	       (t (push-let-binding rest-of-args path nil)
		  (setf restp t))))
      (let ((var (car rest-of-args)))
	(cond ((eq var '&whole)
	       (cond ((and (cdr rest-of-args) (symbolp (cadr rest-of-args)))
		      (setf rest-of-args (cdr rest-of-args))
		      (push-let-binding (car rest-of-args) arg-list-name nil))
		     (t (error "Bad &WHOLE"))))
	      ((eq var '&environment)
	       (cond (env-illegal
		      (error "&Environment not valid with ~S." error-kind))
		     ((not top-level)
		      (error "&Environment only valid at top level of ~
		      lambda-list.")))
	       (cond ((and (cdr rest-of-args) (symbolp (cadr rest-of-args)))
		      (setf rest-of-args (cdr rest-of-args))
		      (push-let-binding (car rest-of-args) env-arg-name nil)
		      (setf env-arg-used t))
		     (t (error "Bad &ENVIRONMENT"))))
	      ((or (eq var '&rest) (eq var '&body))
	       (cond ((and (cdr rest-of-args) (symbolp (cadr rest-of-args)))
		      (setf rest-of-args (cdr rest-of-args))
		      (setf restp t)
		      (push-let-binding (car rest-of-args) path nil))
		     ;;
		     ;; This branch implements an incompatible extension to
		     ;; Common Lisp.  In place of a symbol following &body,
		     ;; there may be a list of up to three elements which will
		     ;; be bound to the body, declarations, and doc-string of
		     ;; the body.
		     ((and (cdr rest-of-args)
			   (consp (cadr rest-of-args))
			   (symbolp (caadr rest-of-args)))
		      (setf rest-of-args (cdr rest-of-args))
		      (setf restp t)
		      (let ((body-name (caar rest-of-args))
			    (declarations-name (cadar rest-of-args))
			    (doc-string-name (caddar rest-of-args))
			    (parse-body-values (gensym)))
			(push-let-binding
			 parse-body-values
			 `(multiple-value-list
			   (parse-body ,path ,env-arg-name
				       ,(not (null doc-string-name))))
			 t)
			(setf env-arg-used t)
			(when body-name
			  (push-let-binding body-name
					    `(car ,parse-body-values) nil))
			(when declarations-name
			  (push-let-binding declarations-name
					    `(cadr ,parse-body-values) nil))
			(when doc-string-name
			  (push-let-binding doc-string-name
					    `(caddr ,parse-body-values) nil))))
		     (t (error "Bad lambda list"))))
	      ((eq var '&optional)
	       (setf now-processing :optionals))
	      ((eq var '&key)
	       (setf now-processing :keywords)
	       (setf rest-name (gensym "KEYWORDS-"))
	       (push rest-name *ignorable-vars*)
	       (setf restp t)
	       (push-let-binding rest-name path t))
	      ((eq var '&allow-other-keys)
	       (setf allow-other-keys-p t))
	      ((eq var '&aux)
	       (setf now-processing :auxs))
	      ((listp var)
	       (case now-processing
		 (:required
		  (let ((sub-list-name (gensym "SUBLIST-")))
		    (push-sub-list-binding sub-list-name `(car ,path) var
					   name error-kind error-fun)
		    (parse-defmacro-lambda-list var sub-list-name name
						error-kind error-fun))
		  (setf path `(cdr ,path))
		  (incf minimum)
		  (incf maximum))
		 (:optionals
		  (when (> (length var) 3)
		    (cerror "Ignore extra noise."
			    "More than variable, initform, and suppliedp ~
			    in &optional binding - ~S"
			    var))
		  (push-optional-binding (car var) (cadr var) (caddr var)
					 `(not (null ,path)) `(car ,path)
					 name error-kind error-fun)
		  (setf path `(cdr ,path))
		  (incf maximum))
		 (:keywords
		  (let* ((keyword-given (consp (car var)))
			 (variable (if keyword-given
				       (cadar var)
				       (car var)))
			 (keyword (if keyword-given
				      (caar var)
				      (make-keyword variable)))
			 (supplied-p (caddr var)))
		    (push-optional-binding variable (cadr var) supplied-p
					   `(keyword-supplied-p ',keyword
								,rest-name)
					   `(lookup-keyword ',keyword
							    ,rest-name)
					   name error-kind error-fun)
		    (push keyword keys)))
		 (:auxs (push-let-binding (car var) (cadr var) nil))))
	      ((symbolp var)
	       (case now-processing
		 (:required
		  (incf minimum)
		  (incf maximum)
		  (push-let-binding var `(car ,path) nil)
		  (setf path `(cdr ,path)))
		 (:optionals
		  (incf maximum)
		  (push-let-binding var `(car ,path) nil `(not (null ,path)))
		  (setf path `(cdr ,path)))
		 (:keywords
		  (let ((key (make-keyword var)))
		    (push-let-binding var `(lookup-keyword ,key ,rest-name)
				      nil)
		    (push key keys)))
		 (:auxs
		  (push-let-binding var nil nil))))
	      (t
	       (error "Non-symbol in lambda-list - ~S." var)))))
    ;; Generate code to check the number of arguments, unless dotted
    ;; in which case length will not work.
    (unless restp
       (push `(unless (<= ,minimum
			  (length (the list ,(if top-level
						 `(cdr ,arg-list-name)
					       arg-list-name)))
			  ,@(unless restp
				    (list maximum)))
		      ,(let ((arg (if top-level
				      `(cdr ,arg-list-name)
				    arg-list-name)))
			 (if (eq error-fun 'error)
			     `(do-arg-count-error ',error-kind ',name ,arg
						  ',lambda-list ,minimum
						  ,(unless restp maximum))
			   `(,error-fun 'defmacro-ll-arg-count-error
				 :kind ',error-kind
				 ,@(when name `(:name ',name))
				 :argument ,arg
				 :lambda-list ',lambda-list
				 :minimum ,minimum
				 ,@(unless restp `(:maximum ,maximum))))))
	     *arg-tests*))
    (if keys
	(let ((problem (gensym "KEY-PROBLEM-"))
	      (info (gensym "INFO-")))
	  (push `(multiple-value-bind
		     (,problem ,info)
		     (verify-keywords ,rest-name ',keys ',allow-other-keys-p)
		   (when ,problem
		     (,error-fun
		      'defmacro-ll-broken-key-list-error
		      :kind ',error-kind
		      ,@(when name `(:name ',name))
		      :problem ,problem
		      :info ,info)))
		*arg-tests*)))
    (values env-arg-used minimum (if (null restp) maximum nil))))


(defun push-sub-list-binding (variable path object name error-kind error-fun)
  (let ((var (gensym "TEMP-")))
    (push `(,variable
	    (let ((,var ,path))
	      (if (listp ,var)
		  ,var
		  (,error-fun 'defmacro-bogus-sublist-error
			      :kind ',error-kind
			      ,@(when name `(:name ',name))
			      :object ,var
			      :lambda-list ',object))))
	  *system-lets*)))

(defun push-let-binding (variable path systemp &optional condition
				  (init-form *default-default*))
  (let ((let-form (if condition
		      `(,variable (if ,condition ,path ,init-form))
		      `(,variable ,path))))
    (if systemp
	(push let-form *system-lets*)
	(push let-form *user-lets*))))

(defun push-optional-binding (value-var init-form supplied-var condition path
					name error-kind error-fun)
  (unless supplied-var
    (setf supplied-var (gensym "SUPLIEDP-")))
  (push-let-binding supplied-var condition t)
  (cond ((consp value-var)
	 (let ((whole-thing (gensym "OPTIONAL-SUBLIST-")))
	   (push-sub-list-binding whole-thing
				  `(if ,supplied-var ,path ,init-form)
				  value-var name error-kind error-fun)
	   (parse-defmacro-lambda-list value-var whole-thing name
				       error-kind error-fun)))
	((symbolp value-var)
	 (push-let-binding value-var path nil supplied-var init-form))
	(t
	 (error "Illegal optional variable name: ~S" value-var))))

;;;; From macros.lisp

;;; Parse-Body  --  Public
;;;
;;;    Parse out declarations and doc strings, *not* expanding macros.
;;; Eventually the environment arg should be flushed, since macros can't expand
;;; into declarations anymore.
;;;
(defun parse-body (body environment &optional (doc-string-allowed t))
  "This function is to parse the declarations and doc-string out of the body of
  a defun-like form.  Body is the list of stuff which is to be parsed.
  Environment is ignored.  If Doc-String-Allowed is true, then a doc string
  will be parsed out of the body and returned.  If it is false then a string
  will terminate the search for declarations.  Three values are returned: the
  tail of Body after the declarations and doc strings, a list of declare forms,
  and the doc-string, or NIL if none."
  (declare (ignore environment))
  (let ((decls ())
	(doc nil))
    (do ((tail body (cdr tail)))
	((endp tail)
	 (values tail (nreverse decls) doc))
      (let ((form (car tail)))
	(cond ((and (stringp form) (cdr tail))
	       (if doc-string-allowed
		   (setq doc form
			 ;; Only one doc string is allowed.
			 doc-string-allowed nil)
		   (return (values tail (nreverse decls) doc))))
	      ((not (and (consp form) (symbolp (car form))))
	       (return (values tail (nreverse decls) doc)))
	      ((eq (car form) 'declare)
	       (push form decls))
	      (t
	       (return (values tail (nreverse decls) doc))))))))

;;;; Destructuring-bind

(defmacro destructuring-bind (lambda-list arg-list &rest body)
  "Bind the variables in LAMBDA-LIST to the contents of ARG-LIST."
  (let* ((arg-list-name (gensym "ARG-LIST-")))
    (multiple-value-bind
	(body local-decls)
	(parse-defmacro lambda-list arg-list-name body nil 'destructuring-bind
			:annonymousp t :doc-string-allowed nil)
      `(let ((,arg-list-name ,arg-list))
	 ,@local-decls
	 ,body))))

