;;; Looks up a source of "{module}.{proc}"
;;; Last edited on 2021-05-30 11:01:17 by jstolfi

(defun stolfi-visit-module-and-proc (arg)
  "Expects to be called when the point is within or adjacent to 
  a function call of the form {module}.{proc}. Searches for the file
  {module}.{ext} in the current directory or some near ancestor thereof, 
  where {ext} is the extension of the current buffer's file. 
  If found, visits that file, then searches
  in it for the presumed definition of {proc}. 
  With a prefix arg, uses the current window. [stolfi]"
  (interactive "P")
  (let*
    ( ( fname (buffer-file-name) )
      ( fext  (file-name-extension fname) )
      ( modproc  (stolfi-grab-module-and-proc nil) )
    )
    (message (concat "modproc = " modproc))
    (if modproc
      (let*
        ( ( mname (file-name-sans-extension modproc) )
          ( mproc (file-name-extension modproc) )
          ( mfile (concat mname "." fext) )
          ( mfile-ex mfile )
          ( defkey (if (equal fext "py") "\\bdef\\b *" "") )
        )
        (message (concat "mfile = " mfile))
        ; Try to find {mfile} in the current directory or near ancestor:
        (if (not (file-exists-p mfile-ex)) (setq mfile-ex (concat "../" mfile-ex)))
        (if (not (file-exists-p mfile-ex)) (setq mfile-ex (concat "../" mfile-ex)))
        (if (not (file-exists-p mfile-ex)) (setq mfile-ex (concat "../" mfile-ex)))
        (if (not (file-exists-p mfile-ex))
          (error (concat "file " mfile " not found"))
          (progn
            (if (null arg)
              (find-file-other-window mfile-ex)
              (find-file mfile-ex)
            ) 
            (if (and mproc (> (length mproc) 1))
              (progn
                (goto-char (point-min))
                (re-search-forward (concat defkey "\\b" mproc "\\b"))
              )
            )
          )
        )
      )
      (error "no valid {module}.{proc} around")
    )
  )
)

(defun stolfi-grab-module-and-proc(arg)
  "Expects to be called when the point is within or adjacent to 
  qualified function name of the form \"{proc}\" or \"{module}.{proc}\". Returns that 
  name as a string."
  (interactive "p")
  ; (message "stolfi-grab-module-and-proc called with arg = %S" arg)
  (save-excursion
    (let* 
      (beg end) 
      ; Search backwars for beginning of qualified name:
      (if (re-search-backward "[^._A-Za-z0-9]" (- (point) 1000) 'beg)
        (forward-char)
      )
      (setq beg (point))
      (if (re-search-forward "[^._A-Za-z0-9]" (+ (point) 1000) 'end)
        (backward-char)
      )
      (setq end (point))
      (if (< beg end)
        (buffer-substring-no-properties beg end)
        nil
      )
    )
  )
)