;; introspection.scm -- name says it all

;; Copyright (C) 2009 Jose Antonio Ortega Ruiz

;; Author: Jose Antonio Ortega Ruiz <jao@gnu.org>
;; Start date: Sun Feb 08, 2009 18:44

;; This file 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 3 of the License, or
;; (at your option) any later version.

;; This file 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, see <http://www.gnu.org/licenses/>.

;;; Comentary:

;; Procedures introspecting on scheme objects and their properties.

;;; Code:

(define-module (geiser introspection)
  #:export (autodoc
            completions
            symbol-location
            symbol-documentation
            all-modules
            module-children
            module-location)
  #:use-module (system vm program)
  #:use-module (ice-9 regex)
  #:use-module (ice-9 session)
  #:use-module (ice-9 documentation)
  #:use-module (oop goops)
  #:use-module (srfi srfi-1))

(define (autodoc form)
  (cond ((null? form) #f)
        ((symbol? form) (describe-application (list form)))
        ((and (pair? form) (not (list? form))) (autodoc (pair->list form)))
        ((list? form)
         (let ((lst (last form)))
           (cond ((symbol? lst) (or (describe-application (list lst))
                                    (describe-application form)))
                 ((pair? lst)
                  (or (autodoc (pair->list lst))
                      (autodoc (map (lambda (s) (if (pair? s) (gensym) s)) form))))
                 (else (describe-application form)))))
        (else #f)))

(define (describe-application form)
  (let* ((fun (car form))
         (args (obj-args (symbol->obj fun))))
    (and args
         (list (cons 'signature (signature fun args))
               (cons 'position (find-position args form))
               (cons 'module (symbol-module fun))))))

(define (pair->list pair)
  (let loop ((d pair) (s '()))
    (cond ((null? d) (reverse! s))
          ((symbol? d) (reverse! (cons d s)))
          (else (loop (cdr d) (cons (car d) s))))))

(define (arglst args kind)
  (let ((args (assq-ref args kind)))
    (cond ((or (not args) (null? args)) '())
          ((list? args) args)
          (else (list args)))))

(define (signature fun args)
  (let ((req (arglst args 'required))
        (opt (arglst args 'optional))
        (key (arglst args 'keyword))
        (rest (assq-ref args 'rest)))
    (let ((sgn `(,fun ,@req
                      ,@(if (not (null? opt)) (cons #:opt opt) '())
                      ,@(if (not (null? key)) (cons #:key key) '()))))
      (if rest `(,@sgn #:rest ,rest) sgn))))

(define (find-position args form)
  (let* ((lf (length form))
         (lf-1 (- lf 1)))
    (if (= 1 lf) 0
        (let ((req (length (arglst args 'required)))
              (opt (length (arglst args 'optional)))
              (keys (map (lambda (k) (symbol->keyword (if (list? k) (car k) k)))
                         (arglst args 'keyword)))
              (rest (assq-ref args 'rest)))
          (cond ((<= lf (+ 1 req)) lf-1)
                ((<= lf (+ 1 req opt)) (if (> opt 0) lf lf-1))
                ((or (memq (last form) keys)
                     (memq (car (take-right form 2)) keys)) =>
                 (lambda (sl)
                   (+ 2 req
                      (if (> opt 0) (+ 1 opt) 0)
                      (- (length keys) (length sl)))))
                (else (+ 1 req
                         (if (> opt 0) (+ 1 opt) 0)
                         (if (null? keys) 0 (+ 1 (length keys)))
                         (if rest 2 0))))))))

(define (symbol-module sym)
  (and sym
       (call/cc
        (lambda (k)
          (apropos-fold (lambda (module name var init)
                          (if (eq? name sym) (k (module-name module)) init))
                        #f
                        (regexp-quote (symbol->string sym))
                        (apropos-fold-accessible (current-module)))))))

(define (symbol->obj sym)
  (and (symbol? sym)
       (module-defined? (current-module) sym)
       (module-ref (current-module) sym)))

(define (obj-args obj)
  (cond ((not obj) #f)
        ((or (procedure? obj) (program? obj)) (arguments obj))
        ((macro? obj) (or (obj-args (macro-transformer obj))
                          '((required ...))))
        (else #f)))

(define (arguments proc)
  (cond
   ((is-a? proc <generic>) (generic-args proc))
   ((procedure-property proc 'arglist) => arglist->args)
   ((procedure-source proc) => source->args)
   ((program? proc) ((@ (system vm program) program-arguments) proc))
   ((procedure-property proc 'arity) => arity->args)
   (else #f)))

(define (source->args src)
  (let ((formals (cadr src)))
    (cond ((list? formals) `((required . ,formals)))
          ((pair? formals)
           `((required . ,(car formals)) (rest . ,(cdr formals))))
          (else #f))))

(define (arity->args art)
  (let ((req (car art))
        (opt (cadr art))
        (rest (caddr art)))
    `(,@(if (> req 0) (list (cons 'required (gen-arg-names 1 req))) '())
      ,@(if (> opt 0) (list (cons 'optional (gen-arg-names (+ 1 req) opt))) '())
      ,@(if rest (list (cons 'rest 'rest)) '()))))

(define (gen-arg-names fst count)
  (map (lambda (n) (string->symbol (format "arg-~A" (+ fst n))))
       (iota (max count 1))))

(define (arglist->args arglist)
  `((required . ,(car arglist))
    (optional . ,(cadr arglist))
    (keyword . ,(caddr arglist))
    (rest . ,(car (cddddr arglist)))))

(define (generic-args gen)
  (define (src> src1 src2)
    (> (length (cadr src1)) (length (cadr src2))))
  (define (src m)
    (catch #t
      (lambda () (method-source m))
      (lambda (k . a) #f)))
  (let* ((methods (generic-function-methods gen))
         (srcs (filter identity (map src methods))))
    (cond ((and (null? srcs) (null? methods)) '((rest . rest)))
          ((and (null? srcs)
                (not (null? methods))
                (method-procedure (car methods)))
           => arguments)
          ((not (null? srcs)) (source->args (car (sort! srcs src>))))
          (else '((rest . rest))))))

(define (completions prefix . context)
  (let ((context (and (not (null? context)) (car context)))
        (prefix (string-append "^" (regexp-quote prefix))))
    (append (filter (lambda (s) (string-match prefix s))
                    (map symbol->string (local-bindings context)))
            (sort! (map symbol->string (apropos-internal prefix)) string<?))))

(define (local-bindings form)
  (define (body f) (if (> (length f) 2) (cddr f) '()))
  (let loop ((form form) (bindings '()))
    (cond ((not (pair? form)) bindings)
          ((list? (car form))
           (loop (cdr form) (append (local-bindings (car form)) bindings)))
          ((and (list? form) (< (length form) 2)) bindings)
          ((memq (car form) '(define define* lambda))
           (loop (body form) (append (pair->list (cadr form)) bindings)))
          ((and (memq (car form) '(let let* letrec letrec*))
                (list? (cadr form)))
           (loop (body form) (append (map car (cadr form)) bindings)))
          ((and (eq? 'let (car form)) (symbol? (cadr form)))
           (loop (cons 'let (body form)) (cons (cadr form) bindings)))
          (else (loop (cdr form) bindings)))))

(define (module-location name)
  (make-location (module-filename name) #f))

(define (symbol-location sym)
  (cond ((symbol-module sym) => module-location)
        (else '())))

(define (make-location file line)
  (list (cons 'file (if (string? file) file '()))
        (cons 'line (if (number? line) (+ 1 line) '()))))

(define module-filename (@@ (ice-9 session) module-filename))

(define (docstring sym obj)
  (with-output-to-string
    (lambda ()
      (let* ((type (cond ((macro? obj) "A macro")
                         ((procedure? obj) "A  procedure")
                         ((program? obj) "A compiled program")
                         (else "An object")))
             (modname (symbol-module sym))
            (doc (object-documentation obj)))
        (display type)
        (if modname
            (begin
              (display " in module ")
              (display modname)))
        (newline)
        (if doc (display doc))))))

(define (obj-signature sym obj)
  (let ((args (obj-args obj)))
    (and args (signature sym args))))

(define (symbol-documentation sym)
  (let ((obj (symbol->obj sym)))
    (if obj
        `((signature . ,(or (obj-signature sym obj) sym))
          (docstring . ,(docstring sym obj))))))

(define (all-modules)
  (let ((roots ((@@ (ice-9 session) root-modules))))
    (sort! (map (lambda (m)
                  (format "~A" (module-name m)))
                (fold (lambda (m all)
                        (append (all-child-modules m) all))
                      roots
                      roots))
           string<?)))

(define (child-modules mod)
  (delq mod ((@@ (ice-9 session) submodules) mod)))

(define (all-child-modules mod)
  (let ((children (child-modules mod)))
    (fold (lambda (m all)
            (append (all-child-modules m) all))
          children children)))

(define (module-children mod-name)
  (let* ((elts (hash-fold classify-module-object
                          (list '() '() '())
                          (module-obarray (maybe-module-interface mod-name))))
         (elts (map sort-symbols! elts)))
    (list (cons 'modules (map (lambda (m) `(,@mod-name ,m)) (car elts)))
          (cons 'procs (cadr elts))
          (cons 'vars (caddr elts)))))

(define (sort-symbols! syms)
  (let ((cmp (lambda (l r)
               (string<? (symbol->string l) (symbol->string r)))))
    (sort! syms cmp)))

(define (maybe-module-interface mod-name)
  (catch #t
         (lambda () (resolve-interface mod-name))
         (lambda args (resolve-module mod-name))))

(define (classify-module-object name var elts)
  (let ((obj (and (variable-bound? var)
                  (variable-ref var))))
    (cond ((not obj) elts)
          ((and (module? obj) (eq? (module-kind obj) 'directory))
           (list (cons name (car elts))
                 (cadr elts)
                 (caddr elts)))
          ((or (procedure? obj) (program? obj) (macro? obj))
           (list (car elts)
                 (cons name (cadr elts))
                 (caddr elts)))
          (else (list (car elts)
                      (cadr elts)
                      (cons name (caddr elts)))))))

;;; introspection.scm ends here