;;; -*-lisp-*-
;;;
;;; $Id$
;;;
;;; Option parser, standard issue
;;;
;;; (c) 2005 Straylight/Edgeware
;;;

;;;----- Licensing notice ---------------------------------------------------
;;;
;;; This program is free software; you can redistribute it and/or modify
;;; it under the terms of the GNU General Public License as published by
;;; the Free Software Foundation; either version 2 of the License, or
;;; (at your option) any later version.
;;;
;;; This program is distributed in the hope that it will be useful,
;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;;; GNU General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with this program; if not, write to the Free Software Foundation,
;;; Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

;;;--------------------------------------------------------------------------
;;; Packages.

(defpackage #:optparse
  (:use #:common-lisp #:mdw.base #:mdw.sys-base)
  (:export #:exit #:*program-name* #:*command-line*
	   #:moan #:die
	   #:option #:optionp #:make-option
	     #:opt-short-name #:opt-long-name #:opt-tag #:opt-negated-tag
	     #:opt-arg-name #:opt-arg-optional-p #:opt-documentation
	   #:option-parser #:make-option-parser #:option-parser-p
	     #:op-options #:op-non-option #:op-long-only-p #:op-numeric-p
	     #:op-negated-numeric-p #:op-negated-p
	   #:option-parse-error
	   #:option-parse-remainder #:option-parse-next #:option-parse-try
	     #:with-unix-error-reporting #:option-parse-return
	   #:defopthandler #:invoke-option-handler
	     #:set #:clear #:inc #:dec #:read #:int #:string
	     #:keyword #:list
	   #:parse-option-form #:options
	   #:simple-usage #:show-usage #:show-version #:show-help
	   #:sanity-check-option-list
	   #:*help* #:*version* #:*usage* #:*options*
	   #:do-options #:help-options
	   #:define-program #:do-usage #:die-usage))

(in-package #:optparse)

;;;--------------------------------------------------------------------------
;;; Standard error-reporting functions.

(defun moan (msg &rest args)
  "Report an error message in the usual way."
  (format *error-output* "~&~A: ~?~%" *program-name* msg args))

(defun die (&rest args)
  "Report an error message and exit."
  (apply #'moan args)
  (exit 1))

;;;--------------------------------------------------------------------------
;;; The main option parser.

(defvar *options* nil)

(defstruct (option
	     (:predicate optionp)
	     (:conc-name opt-)
	     (:print-function
	      (lambda (o s k)
		(declare (ignore k))
		(print-unreadable-object (o s :type t)
		  (format s "~@[-~C, ~]~@[--~A~]~
			     ~*~@[~2:*~:[=~A~;[=~A]~]~]~
			     ~@[ ~S~]"
			  (opt-short-name o)
			  (opt-long-name o)
			  (opt-arg-optional-p o)
			  (opt-arg-name o)
			  (opt-documentation o)))))
	     (:constructor %make-option)
	     (:constructor make-option
		 (long-name short-name
		  &optional arg-name
		  &key (tag (intern (string-upcase long-name) :keyword))
		       negated-tag
		       arg-optional-p
		       doc (documentation doc))))
  "Describes a command-line option.  Slots:

   LONG-NAME	The option's long name.  If this is null, the `option' is
		just a banner to be printed in the program's help text.

   TAG          The value to be returned if this option is encountered.  If
		this is a function, instead, the function is called with the
		option's argument or nil.

   NEGATED-TAG  As for TAG, but used if the negated form of the option is
		found.  If this is nil (the default), the option cannot be
		negated.

   SHORT-NAME   The option's short name.  This must be a single character, or
		nil if the option has no short name.

   ARG-NAME     The name of the option's argument, a string.  If this is nil,
		the option doesn't accept an argument.  The name is shown in
		the help text.

   ARG-OPTIONAL-P
		If non-nil, the option's argument is optional.  This is
		ignored unless ARG-NAME is non-null.

   DOCUMENTATION
		The help text for this option.  It is automatically line-
		wrapped.  If nil, the option is omitted from the help
		text.

   Usually, one won't use make-option, but use the option macro instead."
  (long-name nil :type (or null string))
  (tag nil :type t)
  (negated-tag nil :type t)
  (short-name nil :type (or null character))
  (arg-name nil :type (or null string))
  (arg-optional-p nil :type t)
  (documentation nil :type (or null string)))

(defstruct (option-parser
	     (:conc-name op-)
	     (:constructor make-option-parser
		 (&key ((:args argstmp) (cdr *command-line*))
		       (options *options*)
		       (non-option :skip)
		       ((:numericp numeric-p))
		       negated-numeric-p
		       long-only-p
		  &aux (args (cons nil argstmp))
		       (next args)
		       (negated-p (or negated-numeric-p
				      (some #'opt-negated-tag
					    options))))))
  "An option parser object.  Slots:

   ARGS		The arguments to be parsed.  Usually this will be
		*command-line*.

   OPTIONS      List of option structures describing the acceptable options.

   NON-OPTION   Behaviour when encountering a non-option argument.  The
		default is :skip.  Allowable values are:
		  :skip -- pretend that it appeared after the option
		    arguments; this is the default behaviour of GNU getopt
		  :stop -- stop parsing options, leaving the remaining
		    command line unparsed
		  :return -- return :non-option and the argument word

   NUMERIC-P    Non-nil tag (as for options) if numeric options (e.g., -43)
		are to be allowed.  The default is nil.  (Anomaly: the
		keyword for this argument is :numericp.)

   NEGATED-NUMERIC-P
		Non-nil tag (as for options) if numeric options (e.g., -43)
		can be negated.  This is not the same thing as a negative
		numeric option!

   LONG-ONLY-P  A misnomer inherited from GNU getopt.  Whether to allow
		long options to begin with a single dash.  Short options are
		still allowed, and may be cuddled as usual.  The default is
		nil."
  (args nil :type list)
  (options nil :type list)
  (non-option :skip :type (or function (member :skip :stop :return)))
  (next nil :type list)
  (short-opt nil :type (or null string))
  (short-opt-index 0 :type fixnum)
  (short-opt-neg-p nil :type t)
  (long-only-p nil :type t)
  (numeric-p nil :type t)
  (negated-numeric-p nil :type t)
  (negated-p nil :type t))

(define-condition option-parse-error (error simple-condition)
  ()
  (:documentation
   "Indicates an error found while parsing options.  Probably not that
   useful."))

(defun option-parse-error (msg &rest args)
  "Signal an option-parse-error with the given message and arguments."
  (error (make-condition 'option-parse-error
			 :format-control msg
			 :format-arguments args)))

(defun option-parse-remainder (op)
  "Returns the unparsed remainder of the command line."
  (cdr (op-args op)))

(defun option-parse-return (tag &optional argument)
  "Should be called from an option handler: forces a return from the
   immediately enclosing `option-parse-next' with the given TAG and
   ARGUMENT."
  (throw 'option-parse-return (values tag argument)))

(defun option-parse-next (op)
  "The main option-parsing function.  OP is an option-parser object,
   initialized appropriately.  Returns two values, OPT and ARG: OPT is the
   tag of the next option read, and ARG is the argument attached to it, or
   nil if there was no argument.  If there are no more options, returns nil
   twice.  Options whose TAG is a function aren't returned; instead, the tag
   function is called, with the option argument (or nil) as the only
   argument.  It is safe for tag functions to throw out of option-parse-next,
   if they desparately need to.  (This is the only way to actually get
   option-parse-next to return a function value, should that be what you
   want.  See `option-parse-return' for a way of doing this.)

   While option-parse-next is running, there is a restart `skip-option' which
   moves on to the next option.  Error handlers should use this to resume
   after parsing errors."
  (labels ((ret (opt &optional arg)
	     (return-from option-parse-next (values opt arg)))
	   (finished ()
	     (setf (op-next op) nil)
	     (ret nil nil))
	   (peek-arg ()
	     (cadr (op-next op)))
	   (more-args-p ()
	     (and (op-next op)
		  (cdr (op-next op))))
	   (skip-arg ()
	     (setf (op-next op) (cdr (op-next op))))
	   (eat-arg ()
	     (setf (cdr (op-next op)) (cddr (op-next op))))
	   (get-arg ()
	     (prog1 (peek-arg) (eat-arg)))
	   (process-option (o name negp &key arg argfunc)
	     (cond ((not (opt-arg-name o))
		    (when arg
		      (option-parse-error
		       "Option `~A' does not accept arguments"
		       name)))
		   (arg)
		   (argfunc
		    (setf arg (funcall argfunc)))
		   ((opt-arg-optional-p o))
		   ((more-args-p)
		    (setf arg (get-arg)))
		   (t
		    (option-parse-error "Option `~A' requires an argument"
					name)))
	     (let ((how (if negp (opt-negated-tag o) (opt-tag o))))
	       (if (functionp how)
		   (funcall how arg)
		   (ret how arg))))
	   (process-long-option (arg start negp)
	     (when (and (not negp)
			(op-negated-p op)
			(> (length arg) (+ start 3))
			(string= arg "no-"
				 :start1 start :end1 (+ start 3)))
	       (incf start 3)
	       (setf negp t))
	     (let* ((matches nil)
		    (eqpos (position #\= arg :start start))
		    (len (or eqpos (length arg)))
		    (optname (subseq arg 0 len))
		    (len-2 (- len start)))
	       (dolist (o (op-options op))
		 (cond ((or (not (stringp (opt-long-name o)))
			    (and negp (not (opt-negated-tag o)))
			    (< (length (opt-long-name o)) len-2)
			    (string/= optname (opt-long-name o)
				      :start1 start :end2 len-2)))
		       ((= (length (opt-long-name o)) len-2)
			(setf matches (list o))
			(return))
		       (t
			(push o matches))))
	       (cond ((null matches)
		      (option-parse-error "Unknown option `~A'" optname))
		     ((cdr matches)
		      (option-parse-error
		       #.(concatenate 'string
				      "Ambiguous long option `~A' -- "
				      "could be any of:"
				      "~{~%~8T--~A~}")
		       optname
		       (mapcar #'opt-long-name matches))))
	       (process-option (car matches)
			       optname
			       negp
			       :arg (and eqpos
					 (subseq arg (1+ eqpos)))))))
    (catch 'option-parse-return
      (loop
	(with-simple-restart (skip-option "Skip this bogus option.")
	  (cond
	    ;;
	    ;; We're embroiled in short options: handle them.
	    ((op-short-opt op)
	     (if (>= (op-short-opt-index op) (length (op-short-opt op)))
		 (setf (op-short-opt op) nil)
		 (let* ((str (op-short-opt op))
			(i (op-short-opt-index op))
			(ch (char str i))
			(negp (op-short-opt-neg-p op))
			(name (format nil "~C~A" (if negp #\+ #\-) ch))
			(o (find ch (op-options op) :key #'opt-short-name)))
		   (incf i)
		   (setf (op-short-opt-index op) i)
		   (when (or (not o)
			     (and negp (not (opt-negated-tag o))))
		     (option-parse-error "Unknown option `~A'" name))
		   (process-option o
				   name
				   negp
				   :argfunc
				   (and (< i (length str))
					(lambda ()
					  (prog1
					      (subseq str i)
					    (setf (op-short-opt op)
						  nil))))))))
	    ;;
	    ;; End of the list.  Say we've finished.
	    ((not (more-args-p))
	     (finished))
	    ;;
	    ;; Process the next option.
	    (t
	     (let ((arg (peek-arg)))
	       (cond
		 ;;
		 ;; Non-option.  Decide what to do.
		 ((or (<= (length arg) 1)
		      (and (char/= (char arg 0) #\-)
			   (or (char/= (char arg 0) #\+)
			       (not (op-negated-p op)))))
		  (case (op-non-option op)
		    (:skip (skip-arg))
		    (:stop (finished))
		    (:return (eat-arg)
			     (ret :non-option arg))
		    (t (eat-arg)
		       (funcall (op-non-option op) arg))))
		 ;;
		 ;; Double-hyphen.  Stop right now.
		 ((string= arg "--")
		  (eat-arg)
		  (finished))
		 ;;
		 ;; Numbers.  Check these before long options, since `--43'
		 ;; is not a long option.
		 ((and (op-numeric-p op)
		       (or (char= (char arg 0) #\-)
			   (op-negated-numeric-p op))
		       (or (and (digit-char-p (char arg 1))
				(every #'digit-char-p (subseq arg 2)))
			   (and (or (char= (char arg 1) #\-)
				    (char= (char arg 1) #\+))
				(>= (length arg) 3)
				(digit-char-p (char arg 2))
				(every #'digit-char-p (subseq arg 3)))))
		  (eat-arg)
		  (let ((negp (char= (char arg 0) #\+))
			(num (parse-integer arg :start 1)))
		    (when (and negp (eq (op-negated-numeric-p op) :-))
		      (setf num (- num))
		      (setf negp nil))
		    (let ((how (if negp
				   (op-negated-numeric-p op)
				   (op-numeric-p op))))
		      (if (functionp how)
			  (funcall how num)
			  (ret (if negp :negated-numeric :numeric) num)))))
		 ;;
		 ;; Long option.  Find the matching option-spec and process
		 ;; it.
		 ((and (char= (char arg 0) #\-)
		       (char= (char arg 1) #\-))
		  (eat-arg)
		  (process-long-option arg 2 nil))
		 ;;
		 ;; Short options.  All that's left.
		 (t
		  (eat-arg)
		  (let ((negp (char= (char arg 0) #\+))
			(ch (char arg 1)))
		    (cond ((and (op-long-only-p op)
				(not (member ch (op-options op)
					     :key #'opt-short-name)))
			   (process-long-option arg 1 negp))
			  (t
			   (setf (op-short-opt op) arg
				 (op-short-opt-index op) 1
				 (op-short-opt-neg-p op) negp))))))))))))))

(defmacro option-parse-try (&body body)
  "Report errors encountered while parsing options, and continue struggling
   along.  Also establishes a restart `stop-parsing'.  Returns t if parsing
   completed successfully, or nil if errors occurred."
  (with-gensyms (retcode)
    `(let ((,retcode t))
       (restart-case
	   (handler-bind
	       ((option-parse-error
		 (lambda (cond)
		   (setf ,retcode nil)
		   (moan "~A" cond)
		   (dolist (rn '(skip-option stop-parsing))
		     (let ((r (find-restart rn)))
		       (when r (invoke-restart r)))))))
	     ,@body)
	 (stop-parsing ()
	   :report "Give up parsing options."
	   (setf ,retcode nil)))
       ,retcode)))

(defmacro with-unix-error-reporting ((&key) &body body)
  "Evaluate BODY with errors reported in the standard Unix fashion."
  (with-gensyms (cond)
    `(handler-case
	 (progn ,@body)
       (simple-condition (,cond)
	 (apply #'die
	        (simple-condition-format-control ,cond)
	        (simple-condition-format-arguments ,cond)))
       (error (,cond)
	 (die "~A" ,cond)))))

;;;--------------------------------------------------------------------------
;;; Standard option handlers.

(defmacro defopthandler (name (var &optional (arg (gensym)))
			 (&rest args)
			 &body body)
  "Define an option handler function NAME.  Option handlers update a
   generalized variable, which may be referred to as VAR in the BODY, based
   on some parameters (the ARGS) and the value of an option-argument named
   ARG."
  (let ((func (intern (format nil "OPTHANDLER/~:@(~A~)" name))))
    (with-parsed-body (body decls docs) body
      `(progn
	 (setf (get ',name 'opthandler) ',func)
	 (defun ,func (,var ,arg ,@args)
	   ,@docs ,@decls
	   (with-locatives ,var
	     (declare (ignorable ,arg))
	     ,@body))
	 ',name))))

(defun parse-c-integer (string &key radix (start 0) end)
  "Parse STRING, or at least the parts of it between START and END, according
   to the standard C rules.  Well, almost: the 0 and 0x prefixes are
   accepted, but so too are 0o (Haskell) and 0b (original); also RADIX_DIGITS
   is accepted, for any radix between 2 and 36.  Prefixes are only accepted
   if RADIX is nil.  Returns two values: the integer parsed (or nil if there
   wasn't enough for a sensible parse), and the index following the
   characters of the integer."
  (setf-default end (length string))
  (labels ((simple (i r goodp sgn)
	     (multiple-value-bind
		 (a i)
		 (if (and (< i end)
			  (digit-char-p (char string i) r))
		     (parse-integer string
				    :start i :end end
				    :radix r
				    :junk-allowed t)
		     (values nil i))
	       (values (if a (* sgn a) (and goodp 0)) i)))
	   (get-radix (i r sgn)
	     (cond (r (simple i r nil sgn))
		   ((>= i end) (values nil i))
		   ((and (char= (char string i) #\0)
			 (>= (- end i) 2))
		    (case (char string (1+ i))
		      (#\x (simple (+ i 2) 16 nil sgn))
		      (#\o (simple (+ i 2) 8 nil sgn))
		      (#\b (simple (+ i 2) 2 nil sgn))
		      (t (simple (1+ i) 8 t sgn))))
		   (t
		    (multiple-value-bind
			(r i)
			(simple i 10 nil +1)
		      (cond ((not r) (values nil i))
			    ((and (< i end)
				  (char= (char string i) #\_)
				  (<= 2 r 36))
			     (simple (1+ i) r nil sgn))
			    (t
			     (values (* r sgn) i))))))))
    (cond ((>= start end) (values nil start))
	  ((char= (char string start) #\-)
	   (get-radix (1+ start) radix -1))
	  ((char= (char string start) #\+)
	   (get-radix (1+ start) radix +1))
	  (t
	   (get-radix start radix +1)))))

(defun invoke-option-handler (handler loc arg args)
  "Call the HANDLER function, giving it LOC to update, the option-argument
   ARG, and the remaining ARGS."
  (apply (if (functionp handler) handler
	     (fdefinition (get handler 'opthandler)))
	 loc
	 arg
	 args))

;;;--------------------------------------------------------------------------
;;; Built-in option handlers.

(defopthandler set (var) (&optional (value t))
  "Sets VAR to VALUE; defaults to t."
  (setf var value))

(defopthandler clear (var) (&optional (value nil))
  "Sets VAR to VALUE; defaults to nil."
  (setf var value))

(defopthandler inc (var) (&optional max (step 1))
  "Increments VAR by STEP (defaults to 1), but not greater than MAX (default
   nil for no maximum).  No errors are signalled."
  (incf var step)
  (when (>= var max)
    (setf var max)))

(defopthandler dec (var) (&optional min (step 1))
  "Decrements VAR by STEP (defaults to 1), but not less than MIN (default nil
   for no maximum).  No errors are signalled."
  (decf var step)
  (when (<= var min)
    (setf var min)))

(defopthandler read (var arg) ()
  "Stores in VAR the Lisp object found by reading the ARG.  Evaluation is
   forbidden while reading ARG.  If there is an error during reading, an
   error of type option-parse-error is signalled."
  (handler-case
      (let ((*read-eval* nil))
	(multiple-value-bind (x end) (read-from-string arg t)
	  (unless (>= end (length arg))
	    (option-parse-error "Junk at end of argument `~A'" arg))
	  (setf var x)))
    (error (cond)
      (option-parse-error (format nil "~A" cond)))))

(defopthandler int (var arg) (&key radix min max)
  "Stores in VAR the integer read from the ARG.  Integers are parsed
   according to C rules, which is normal in Unix; the RADIX may be nil to
   allow radix prefixes, or an integer between 2 and 36.  An
   option-parse-error is signalled if the ARG is not a valid integer, or if
   it is not between MIN and MAX (either of which may be nil if no lower
   resp. upper bound is wanted)."
  (multiple-value-bind (v end) (parse-c-integer arg :radix radix)
    (unless (and v (>= end (length arg)))
      (option-parse-error "Bad integer `~A'" arg))
    (when (or (and min (< v min))
	      (and max (> v max)))
      (option-parse-error
       #.(concatenate 'string
		      "Integer ~A out of range "
		      "(must have ~@[~D <= ~]x~@[ <= ~D~])")
       arg min max))
    (setf var v)))

(defopthandler string (var arg) ()
  "Stores ARG in VAR, just as it is."
  (setf var arg))

(defopthandler keyword (var arg) (&optional (valid t))
  "Converts ARG into a keyword.  If VALID is t, then any ARG string is
   acceptable: the argument is uppercased and interned in the keyword
   package.  If VALID is a list, then we ensure that ARG matches one of the
   elements of the list; unambigious abbreviations are allowed."
  (etypecase valid
    ((member t)
     (setf var (intern (string-upcase arg) :keyword)))
    (list
     (let ((matches nil)
	   (guess (string-upcase arg))
	   (len (length arg)))
       (dolist (k valid)
	 (let* ((kn (symbol-name k))
		(klen (length kn)))
	   (cond ((string= kn guess)
		  (setf matches (list k))
		  (return))
		 ((and (< len klen)
		       (string= guess kn :end2 len))
		  (push k matches)))))
       (cond
	 ((null matches)
	  (option-parse-error #.(concatenate 'string
					     "Argument `~A' invalid: "
					     "must be one of:"
					     "~{~%~8T~(~A~)~}")
			      arg valid))
	 ((null (cdr matches))
	  (setf var (car matches)))
	 (t
	  (option-parse-error #.(concatenate 'string
					     "Argument `~A' ambiguous: "
					     "may be any of:"
					     "~{~%~8T~(~A~)~}")
			      arg matches)))))))

(defopthandler list (var arg) (&optional handler &rest handler-args)
  "Collect ARGs in a list at VAR.  ARGs are translated by the HANDLER first,
   if specified.  If not, it's as if you asked for `string'."
  (when handler
    (invoke-option-handler handler (locf arg) arg handler-args))
  (setf var (nconc var (list arg))))

;;;--------------------------------------------------------------------------
;;; Option descriptions.

(defmacro defoptmacro (name args &body body)
  "Defines an option macro NAME.  Option macros should produce a list of
   expressions producing one option structure each."
  `(progn
     (setf (get ',name 'optmacro) (lambda ,args ,@body))
     ',name))

(compile-time-defun parse-option-form (form)
  "Does the heavy lifting for parsing an option form.  See the docstring for
   the `option' macro for details of the syntax."
  (flet ((doc (form)
	   (cond ((stringp form) form)
		 ((null (cdr form)) (car form))
		 (t `(format nil ,@form))))
	 (docp (form)
	   (or (stringp form)
	       (and (consp form)
		    (stringp (car form))))))
    (cond ((stringp form)
	   `(%make-option :documentation ,form))
	  ((not (listp form))
	   (error "option form must be string or list"))
	  ((and (docp (car form)) (null (cdr form)))
	   `(%make-option :documentation ,(doc (car form))))
	  (t
	   (let (long-name short-name
		 arg-name arg-optional-p
		 tag negated-tag
		 doc)
	     (dolist (f form)
	       (cond ((and (or (not tag) (not negated-tag))
			   (or (keywordp f)
			       (and (consp f)
				    (member (car f) '(lambda function)))))
		      (if tag
			  (setf negated-tag f)
			  (setf tag f)))
		     ((and (not long-name)
			   (or (rationalp f)
			       (symbolp f)
			       (stringp f)))
		      (setf long-name (if (stringp f) f
					  (format nil "~(~A~)" f))))
		     ((and (not short-name)
			   (characterp f))
		      (setf short-name f))
		     ((and (not doc)
			   (docp f))
		      (setf doc (doc f)))
		     ((and (consp f) (symbolp (car f)))
		      (case (car f)
			(:short-name (setf short-name (cadr f)))
			(:long-name (setf long-name (cadr f)))
			(:tag (setf tag (cadr f)))
			(:negated-tag (setf negated-tag (cadr f)))
			(:arg (setf arg-name (cadr f)))
			(:opt-arg (setf arg-name (cadr f))
				  (setf arg-optional-p t))
			(:doc (setf doc (doc (cdr f))))
			(t (let ((handler (get (car f) 'opthandler)))
			     (unless handler
			       (error "No handler `~S' defined." (car f)))
			     (let* ((var (cadr f))
				    (arg (gensym))
				    (thunk `#'(lambda (,arg)
						(,handler (locf ,var)
							  ,arg
							  ,@(cddr f)))))
			       (if tag
				   (setf negated-tag thunk)
				   (setf tag thunk)))))))
		     (t
		      (error "Unexpected thing ~S in option form." f))))
	     `(make-option ,long-name ,short-name ,arg-name
			   ,@(and arg-optional-p `(:arg-optional-p t))
			   ,@(and tag `(:tag ,tag))
			   ,@(and negated-tag `(:negated-tag ,negated-tag))
			   ,@(and doc `(:documentation ,doc))))))))

(defmacro options (&rest optlist)
  "More convenient way of initializing options.  The OPTLIST is a list of
   OPTFORMS.  Each OPTFORM is one of the following:

   STRING	A banner to print.

   SYMBOL or (SYMBOL STUFF...)
		If SYMBOL is an optform macro, the result of invoking it.

   (...)	A full option-form.  See below.

   Full option-forms are a list of the following kinds of items.

   (:short-name CHAR)
   (:long-name STRING)
   (:arg STRING)
   (:tag TAG)
   (:negated-tag TAG)
   (:doc STRING)
		Set the appropriate slot of the option to the given value.
		The argument is evaluated.

   (:doc FORMAT-CONTROL ARGUMENTS...)
		As for (:doc (format nil FORMAT-CONTROL ARGUMENTS...)).

   KEYWORD, (function ...), (lambda ...)
		If no TAG is set yet, then as a TAG; otherwise as the
		NEGATED-TAG.

   STRING (or SYMBOL or RATIONAL)
		If no LONG-NAME seen yet, then the LONG-NAME.  For symbols
		and rationals, the item is converted to a string and squashed
		to lower-case.

   CHARACTER	If no SHORT-NAME, then the SHORT-NAME.

   STRING or (STRING STUFF...)
		If no DOCUMENTATION set yet, then the DOCUMENTATION string,
		as for (:doc STRING STUFF...)

   (:opt-arg NAME)
		Set the ARG-NAME, and also set ARG-OPTIONAL-P.

   (HANDLER VAR ARGS...)
		If no TAG is set yet, attach the HANDLER to this option,
		giving it ARGS.  Otherwise, set the NEGATED-TAG."

  `(list ,@(mapcan (lambda (form)
		     (multiple-value-bind
			 (sym args)
			 (cond ((symbolp form) (values form nil))
			       ((and (consp form) (symbolp (car form)))
				(values (car form) (cdr form)))
			       (t (values nil nil)))
		       (let ((macro (and sym (get sym 'optmacro))))
			 (if macro
			     (apply macro args)
			     (list (parse-option-form form))))))
		   optlist)))

;;;--------------------------------------------------------------------------
;;; Support stuff for help and usage messages.

(defun print-text (string
		   &optional
		   (stream *standard-output*)
		   &key
		   (start 0)
		   (end nil))
  "Prints STRING to a pretty-printed STREAM, breaking it at whitespace and
   newlines in the obvious way.  Stuff between square brackets is not broken:
   this makes usage messages work better."
  (let ((i start)
	(nest 0)
	(splitp nil))
    (flet ((emit ()
	     (write-string string stream :start start :end i)
	     (setf start i)))
      (setf-default end (length string))
      (loop
	 (unless (< i end)
	   (emit)
	   (return))
	 (let ((ch (char string i)))
	   (cond ((char= ch #\newline)
		  (emit)
		  (incf start)
		  (pprint-newline :mandatory stream))
		 ((whitespace-char-p ch)
		  (when (zerop nest)
		    (setf splitp t)))
		 (t
		  (when splitp
		    (emit)
		    (pprint-newline :fill stream))
		  (setf splitp nil)
		  (case ch
		    (#\[ (incf nest))
		    (#\] (when (plusp nest) (decf nest))))))
	   (incf i))))))

(defun simple-usage (opts &optional mandatory-args)
  "Build a simple usage list from a list of options, and (optionally)
   mandatory argument names."
  (let (short-simple long-simple short-arg long-arg)
    (dolist (o opts)
      (cond ((not (and (opt-documentation o)
		       (opt-long-name o))))
	    ((and (opt-short-name o) (opt-arg-name o))
	     (push o short-arg))
	    ((opt-short-name o)
	     (push o short-simple))
	    ((opt-arg-name o)
	     (push o long-arg))
	    (t
	     (push o long-simple))))
    (list
     (nconc (and short-simple
		 (list (format nil "[-~{~C~}]"
			       (sort (mapcar #'opt-short-name short-simple)
				     #'char<))))
	    (and long-simple
		 (mapcar (lambda (o)
			   (format nil "[--~A]" (opt-long-name o)))
			 (sort long-simple #'string< :key #'opt-long-name)))
	    (and short-arg
		 (mapcar (lambda (o)
			   (format nil "~:[[-~C ~A]~;[-~C[~A]]~]"
				   (opt-arg-optional-p o)
				   (opt-short-name o)
				   (opt-arg-name o)))
			 (sort short-arg #'char-lessp
			       :key #'opt-short-name)))
	    (and long-arg
		 (mapcar (lambda (o)
			   (format nil "~:[[--~A ~A]~;[--~A[=~A]]~]"
				   (opt-arg-optional-p o)
				   (opt-long-name o)
				   (opt-arg-name o)))
			 (sort long-arg #'string-lessp
			       :key #'opt-long-name)))
	    (listify mandatory-args)))))

(defun show-usage (prog usage &optional (stream *standard-output*))
  "Basic usage-showing function.  PROG is the program name, probably from
   *command-line*.  USAGE is a list of possible usages of the program, each
   of which is a list of items to be supplied by the user.  In simple cases,
   a single string is sufficient."
  (pprint-logical-block (stream nil :prefix "Usage: ")
    (dolist (u (listify usage))
      (pprint-logical-block (stream nil
				    :prefix (concatenate 'string prog " "))
	(format stream "~{~A ~:_~}" (listify u)))
      (pprint-newline :mandatory stream))))

(defun show-options-help (opts &optional (stream *standard-output*))
  "Write help for OPTS to the STREAM.  This is the core of the `show-help'
   function."
  (let (newlinep)
    (dolist (o opts)
      (let ((doc (opt-documentation o)))
	(cond ((not o))
	      ((not (opt-long-name o))
	       (when newlinep
		 (terpri stream)
		 (setf newlinep nil))
	       (pprint-logical-block (stream nil)
		 (print-text doc stream))
	       (terpri stream))
	      (t
	       (setf newlinep t)
	       (pprint-logical-block (stream nil :prefix "  ")
		 (format stream "~:[   ~;-~:*~C,~] --~A"
			 (opt-short-name o)
			 (opt-long-name o))
		 (when (opt-arg-name o)
		   (format stream "~:[=~A~;[=~A]~]"
			   (opt-arg-optional-p o)
			   (opt-arg-name o)))
		 (write-string "  " stream)
		 (pprint-tab :line 30 1 stream)
		 (pprint-indent :block 30 stream)
		 (print-text doc stream))
	       (terpri stream)))))))

(defun show-help (prog ver usage opts &optional (stream *standard-output*))
  "Basic help-showing function.  PROG is the program name, probably from
   *command-line*.  VER is the program's version number.  USAGE is a list of
   the possible usages of the program, each of which may be a list of items
   to be supplied.  OPTS is the list of supported options, as provided to the
   options parser.  STREAM is the stream to write on."
  (format stream "~A, version ~A~2%" prog ver)
  (show-usage prog usage stream)
  (terpri stream)
  (show-options-help opts stream))

(defun sanity-check-option-list (opts)
  "Check the option list OPTS for basic sanity.  Reused short and long option
   names are diagnosed.  Maybe other problems will be reported later.
   Returns a list of warning strings."
  (let ((problems nil)
	(longs (make-hash-table :test #'equal))
	(shorts (make-hash-table)))
    (flet ((problem (msg &rest args)
	     (push (apply #'format nil msg args) problems)))
      (dolist (o opts)
	(push o (gethash (opt-long-name o) longs))
	(push o (gethash (opt-short-name o) shorts)))
      (maphash (lambda (k v)
		 (when (and k (cdr v))
		   (problem "Long name `--~A' reused in ~S" k v)))
	       longs)
      (maphash (lambda (k v)
		 (when (and k (cdr v))
		   (problem "Short name `-~C' reused in ~S" k v)))
	       shorts)
      problems)))

;;;--------------------------------------------------------------------------
;;; Full program descriptions.

(defvar *help* nil)
(defvar *version* "<unreleased>")
(defvar *usage* nil)

(defun do-usage (&optional (stream *standard-output*))
  (show-usage *program-name* *usage* stream))

(defun die-usage ()
  (do-usage *error-output*)
  (exit 1))

(defun opt-help (arg)
  (declare (ignore arg))
  (show-help *program-name* *version* *usage* *options*)
  (typecase *help*
    (string (terpri) (write-string *help*))
    (null nil)
    ((or function symbol) (terpri) (funcall *help*)))
  (format t "~&")
  (exit 0))
(defun opt-version (arg)
  (declare (ignore arg))
  (format t "~A, version ~A~%" *program-name* *version*)
  (exit 0))
(defun opt-usage (arg)
  (declare (ignore arg))
  (do-usage)
  (exit 0))

(defoptmacro help-options (&key (short-help #\h)
				(short-version #\v)
				(short-usage #\u))
  "Inserts a standard help options collection in an options list."
  (flet ((shortform (char)
	   (and char (list char))))
    (mapcar
     #'parse-option-form
     `("Help options"
       (,@(shortform short-help) "help" #'opt-help
	"Show this help message.")
       (,@(shortform short-version) "version" #'opt-version
	("Show ~A's version number." *program-name*))
       (,@(shortform short-usage) "usage" #'opt-usage
	("Show a very brief usage summary for ~A." *program-name*))))))

(defun define-program (&key
		       (program-name nil progp)
		       (help nil helpp)
		       (version nil versionp)
		       (usage nil usagep)
		       (full-usage nil fullp)
		       (options nil optsp))
  "Sets up all the required things a program needs to have to parse options
   and respond to them properly."
  (when progp (setf *program-name* program-name))
  (when helpp (setf *help* help))
  (when versionp (setf *version* version))
  (when optsp (setf *options* options))
  (cond ((and usagep fullp) (error "conflicting options"))
	(usagep (setf *usage* (simple-usage *options* usage)))
	(fullp (setf *usage* full-usage))))

(defmacro do-options ((&key (parser '(make-option-parser)))
		      &body clauses)
  "Handy all-in-one options parser macro.  PARSER defaults to a new options
   parser using the preset default options structure.  The CLAUSES are
   `case2'-like clauses to match options, and must be exhaustive.  If there
   is a clause (nil (REST) FORMS...) then the FORMS are evaluated after
   parsing is done with REST bound to the remaining command-line arguments."
  (let*/gensyms (parser)
    `(progn
       (loop
	 (,(if (find t clauses :key #'car) 'case2 'ecase2)
	     (option-parse-next ,parser)
	   ((nil) () (return))
	   ,@(remove-if #'null clauses :key #'car)))
       ,@(let ((tail (find nil clauses :key #'car)))
	   (and tail
		(destructuring-bind ((&optional arg) &rest forms) (cdr tail)
		  (if arg
		      (list `(let ((,arg (option-parse-remainder ,parser)))
			      ,@forms))
		      forms)))))))

;;;----- That's all, folks --------------------------------------------------