;;;; 	Copyright (C) 1997, 2000, 2001 Free Software Foundation, Inc.
;;;;
;;;; 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, 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 software; see the file COPYING.  If not, write to
;;;; the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
;;;; Boston, MA 02111-1307 USA
;;;;


(define-module (ice-9 session)
  :use-module (ice-9 documentation)
  :use-module (ice-9 regex)
  :use-module (ice-9 rdelim))



;;; Documentation
;;;
(define-public help
  (procedure->syntax
    (lambda (exp env)
      "(help [NAME])
Prints useful information.  Try `(help)'."
      (cond ((not (= (length exp) 2))
	     (help-usage))
	    ((not (feature? 'regex))
	     (display "`help' depends on the `regex' feature.
You don't seem to have regular expressions installed.\n"))
	    (else
	     (let ((name (cadr exp)))
	       (cond ((symbol? name)
		      (help-doc name
				(string-append "^"
					       (regexp-quote
						(symbol->string name))
					       "$")))
		     ((string? name)
		      (help-doc name name))
		     ((and (list? name)
			   (= (length name) 2)
			   (eq? (car name) 'unquote))
		      (let ((doc (object-documentation (local-eval (cadr name)
								   env))))
			(if (not doc)
			    (simple-format #t "No documentation found for ~S\n"
					   (cadr name))
                            (write-line doc))))
                     ((and (list? name)
                           (and-map symbol? name)
                           (not (null? name))
                           (not (eq? (car name) 'quote)))
                      (let ((doc (module-commentary name)))
                        (if (not doc)
                            (simple-format
                             #t "No commentary found for module ~S\n" name)
                            (begin
                              (display name) (write-line " commentary:")
                              (write-line doc)))))
		     (else
		      (help-usage)))
	       *unspecified*))))))

(define (module-filename name)          ; fixme: better way? / done elsewhere?
  (let* ((name (map symbol->string name))
         (reverse-name (reverse name))
	 (leaf (car reverse-name))
	 (dir-hint-module-name (reverse (cdr reverse-name)))
	 (dir-hint (apply string-append
                          (map (lambda (elt)
                                 (string-append elt "/"))
                               dir-hint-module-name))))
    (%search-load-path (in-vicinity dir-hint leaf))))

(define (module-commentary name)
  (cond ((module-filename name) => file-commentary)
        (else #f)))

(define (help-doc term regexp)
  (let ((entries (apropos-fold (lambda (module name object data)
				 (cons (list module
					     name
					     (object-documentation object)
					     (cond ((closure? object)
						    "a procedure")
						   ((procedure? object)
						    "a primitive procedure")
						   (else
						    "an object")))
				       data))
			       '()
			       regexp
			       apropos-fold-exported))
	(module car)
	(name cadr)
	(doc caddr)
	(type cadddr))
    (if (null? entries)
	;; no matches
	(begin
	  (display "Did not find any object ")
	  (simple-format #t
			 (if (symbol? term)
			     "named `~A'\n"
			     "matching regexp \"~A\"\n")
			 term))
	(let ((first? #t)
	      (undocumented-entries '())
	      (documented-entries '())
	      (documentations '()))

	  (for-each (lambda (entry)
		      (let ((entry-summary (simple-format #f
							  "~S: ~S\n"
							  (module-name (module entry))
							  (name entry))))
			(if (doc entry)
			    (begin
			      (set! documented-entries
				    (cons entry-summary documented-entries))
			      ;; *fixme*: Use `describe' when we have GOOPS?
			      (set! documentations
				    (cons (simple-format #f
							 "`~S' is ~A in the ~S module.\n\n~A\n"
							 (name entry)
							 (type entry)
							 (module-name (module entry))
							 (doc entry))
					  documentations)))
			    (set! undocumented-entries
				  (cons entry-summary undocumented-entries)))))
		    entries)

	  (if (and (not (null? documented-entries))
		   (or (> (length documented-entries) 1)
		       (not (null? undocumented-entries))))
	      (begin
		(display "Documentation found for:\n")
		(for-each (lambda (entry) (display entry)) documented-entries)
		(set! first? #f)))

	  (for-each (lambda (entry)
		      (if first?
			  (set! first? #f)
			  (newline))
		      (display entry))
		    documentations)

	  (if (not (null? undocumented-entries))
	      (begin
		(if first?
		    (set! first? #f)
		    (newline))
		(display "No documentation found for:\n")
		(for-each (lambda (entry) (display entry)) undocumented-entries)))))))

(define (help-usage)
  (display "Usage: (help NAME) gives documentation about objects named NAME (a symbol)
       (help REGEXP) ditto for objects with names matching REGEXP (a string)
       (help ,EXPR) gives documentation for object returned by EXPR
       (help (my module)) gives module commentary for `(my module)'
       (help) gives this text

`help' searches among bindings exported from loaded modules, while
`apropos' searches among bindings visible from the \"current\" module.

Examples: (help help)
          (help cons)
          (help \"output-string\")

Other useful sources of helpful information:

(apropos STRING)
(arity PROCEDURE)
(name PROCEDURE-OR-MACRO)
(source PROCEDURE-OR-MACRO)

Tools:

(backtrace)				;show backtrace from last error
(debug)					;enter the debugger
(trace [PROCEDURE])			;trace procedure (no arg => show)
(untrace [PROCEDURE])			;untrace (no arg => untrace all)

(OPTIONSET-options 'full)		;display option information
(OPTIONSET-enable 'OPTION)
(OPTIONSET-disable 'OPTION)
(OPTIONSET-set! OPTION VALUE)

where OPTIONSET is one of debug, read, eval, print

"))

;;; {Apropos}
;;;
;;; Author: Roland Orre <orre@nada.kth.se>
;;;

(define-public (apropos rgx . options)
  "Search for bindings: apropos regexp {options= 'full 'shadow 'value}"
  (if (zero? (string-length rgx))
      "Empty string not allowed"
      (let* ((match (make-regexp rgx))
	     (modules (cons (current-module)
			    (module-uses (current-module))))
	     (separator #\tab)
	     (shadow (member 'shadow options))
	     (value (member 'value options)))
	(cond ((member 'full options)
	       (set! shadow #t)
	       (set! value #t)))
	(for-each
	 (lambda (module)
	   (let* ((builtin (or (eq? module the-scm-module)
			       (eq? module the-root-module)))
		  (name (module-name module))
		  (obarray (if builtin
			       (builtin-bindings)
			       (module-obarray module)))
		  (get-ref (if builtin
			       identity
			       variable-ref)))
	     (array-for-each
	      (lambda (oblist)
		(for-each
		 (lambda (x)
		   (cond ((regexp-exec match (symbol->string (car x)))
			  (display name)
			  (display ": ")
			  (display (car x))
			  (cond ((procedure? (get-ref (cdr x)))
				 (display separator)
				 (display (get-ref (cdr x))))
				(value
				 (display separator)
				 (display (get-ref (cdr x)))))
			  (if (and shadow
				   (not (eq? (module-ref module
							 (car x))
					     (module-ref (current-module)
							 (car x)))))
			      (display " shadowed"))
			  (newline)
			  )))
		 oblist))
	      obarray)))
	 modules))))

(define-public (apropos-internal rgx)
  "Return a list of accessible variable names."
  (apropos-fold (lambda (module name var data)
		  (cons name data))
		'()
		rgx
		(apropos-fold-accessible (current-module))))

(define-public (apropos-fold proc init rgx folder)
  "Folds PROCEDURE over bindings matching third arg REGEXP.

Result is

  (PROCEDURE MODULE1 NAME1 VALUE1
    (PROCEDURE MODULE2 NAME2 VALUE2
      ...
      (PROCEDURE MODULEn NAMEn VALUEn INIT)))

where INIT is the second arg to `apropos-fold'.

Fourth arg FOLDER is one of

  (apropos-fold-accessible MODULE) ;fold over bindings accessible in MODULE
  apropos-fold-exported		   ;fold over all exported bindings
  apropos-fold-all		   ;fold over all bindings"
  (let ((match (make-regexp rgx))
	(recorded (make-vector 61 '())))
    (let ((fold-module
	   (lambda (module data)
	     (let* ((obarray-filter
		     (lambda (name val data)
		       (if (and (regexp-exec match (symbol->string name))
				(not (hashq-get-handle recorded name)))
			   (begin
			     (hashq-set! recorded name #t)
			     (proc module name val data))
			   data)))
		    (module-filter
		     (lambda (name var data)
		       (obarray-filter name (variable-ref var) data))))
	       (cond ((or (eq? module the-scm-module)
			  (eq? module the-root-module))
		      (hash-fold obarray-filter
				 data
				 (builtin-bindings)))
		     (module (hash-fold module-filter
					data
					(module-obarray module)))
		     (else data))))))
      (folder fold-module init))))

(define (make-fold-modules init-thunk traverse extract)
  "Return procedure capable of traversing a forest of modules.
The forest traversed is the image of the forest generated by root
modules returned by INIT-THUNK and the generator TRAVERSE.
It is an image under the mapping EXTRACT."
  (lambda (fold-module init)
    (let* ((table (make-hash-table 31))
	   (first? (lambda (obj)
		     (let* ((handle (hash-create-handle! table obj #t))
			    (first? (cdr handle)))
		       (set-cdr! handle #f)
		       first?))))
      (let rec ((data init)
		(modules (init-thunk)))
	(do ((modules modules (cdr modules))
	     (data data (if (first? (car modules))
			    (rec (fold-module (extract (car modules)) data)
				 (traverse (car modules)))
			    data)))
	    ((null? modules) data))))))

(define-public (apropos-fold-accessible module)
  (make-fold-modules (lambda () (list module))
		     module-uses
		     (lambda (x) x)))

(define (root-modules)
  (cons the-root-module
	(submodules (nested-ref the-root-module '(app modules)))))

(define (submodules m)
  (hash-fold (lambda (name var data)
	       (let ((obj (variable-ref var)))
		 (if (and (module? obj)
			  (eq? (module-kind obj) 'directory))
		     (cons obj data)
		     data)))
	     '()
	     (module-obarray m)))

(define-public apropos-fold-exported
  (make-fold-modules root-modules submodules module-public-interface))

(define-public apropos-fold-all
  (make-fold-modules root-modules submodules (lambda (x) x)))

(define-public (source obj)
  (cond ((procedure? obj) (procedure-source obj))
	((macro? obj) (procedure-source (macro-transformer obj)))
	(else #f)))

(define-public (arity obj)
  (let ((arity (procedure-property obj 'arity)))
    (display (car arity))
    (cond ((caddr arity)
	   (display " or more"))
	  ((not (zero? (cadr arity)))
	   (display " required and ")
	   (display (cadr arity))
	   (display " optional")))
    (if (and (not (caddr arity))
	     (= (car arity) 1)
	     (<= (cadr arity) 1))
	(display " argument")
	(display " arguments"))
    (if (closure? obj)
	(let ((formals (cadr (procedure-source obj))))
	  (if (pair? formals)
	      (begin
		(display ": `")
		(display (car formals))
		(let loop ((ls (cdr formals)))
		  (cond ((null? ls)
			 (display #\'))
			((not (pair? ls))
			 (display "', the rest in `")
			 (display ls)
			 (display #\'))
			(else
			 (if (pair? (cdr ls))
			     (display "', `")
			     (display "' and `"))
			 (display (car ls))
			 (loop (cdr ls))))))
	      (begin
		(display " in `")
		(display formals)
		(display #\')))))
    (display ".\n")))

(define-public system-module
  (procedure->syntax
   (lambda (exp env)
     (let* ((m (nested-ref the-root-module
			   (append '(app modules) (cadr exp)))))
       (if (not m)
	   (error "Couldn't find any module named" (cadr exp)))
       (let ((s (not (procedure-property (module-eval-closure m)
					 'system-module))))
	 (set-system-module! m s)
	 (string-append "Module " (symbol->string (module-name m))
			" is now a " (if s "system" "user") " module."))))))