#lang scheme
(require scheme/foreign)
(unsafe!)

#| Convert nested strings to a string of tab indented lines |#
(define (sexp->tab-lines s (indent ""))
  (if (list? s)
      (apply string-append (map (lambda (s) (sexp->tab-lines s (string-append indent "\t"))) s))
      (string-append indent s "\n")))


; Dynamically load the python shared library (version 2.6.1 on my system)
(define py (ffi-lib "libpython2.6" "1"))
;
; Get a function from it, of type string -> int, mirrored as a scheme function.
(define py-run-simple-string (get-ffi-obj "PyRun_SimpleString" py (_fun _string -> _int)))
;
; Get, and immediately call, Py_Initialize to start python.
((get-ffi-obj "Py_Initialize" py (_fun -> _void)))

; Run a pygtk Hello World.
;   - blocks the GUI, so close the pygtk window to get DrScheme control back.
(for-each py-run-simple-string
          (map sexp->tab-lines
               
               '("import pygtk"
                 "import gtk"
                 
                 ("class HelloWorld:"
                  ("def delete_event(self, widget, event, data=None):"
                   ("return False"))
                  ("def destroy(self, widget, data=None):"
                   ("gtk.main_quit()"))
                  ("def __init__(self):"
                   ("self.window = gtk.Window(gtk.WINDOW_TOPLEVEL)"
                    "self.window.connect(\"delete_event\", self.delete_event)"
                    "self.window.connect(\"destroy\", self.destroy)"
                    "self.window.show()"))
                  ("def main(self):"
                   ("gtk.main()")))
                 
                 "hello = HelloWorld()"
                 "hello.main()")))


#| Some informative noodling
(define py-init (get-ffi-obj "Py_Initialize" py (_cprocedure '() _void)))

((get-ffi-obj "Py_IsInitialized" py (_cprocedure '() _int)))
(define py-init? (get-ffi-obj "Py_IsInitialized" py (_cprocedure '() _bool)))
(py-init?)

(py-run-simple-string "print \"csc150\"") ; seen, e.g., in terminal if drscheme launched from there
(for-each (compose display py-run-simple-string)) |#