;; ----- Basics, Attributes ------------

;; print - method on Objects, prints the object
;; space - object, contains the space character

(class Element
    [subclass-of Object]
    [ivars tag atts]

    (class-method new: (t)
        ((super new) init: t))

    (method init: (t)
        (set tag t)
        (set atts (Dictionary new))
        self)

    (method attribute:put: (k v)
        (atts at:put: k v)
        self)

    (method print ()
        ('< print)
        (tag print)
        (atts associationsDo:
            [block (assoc)
                (space print)
                ((assoc key) print)
                ('=" print)
                ((assoc value) print)
                ('=" print)])
        ('/> print)
        self)
)


















;; ----- An SVG canvas -----------------

;; A placeholder class that helps us define a helper-method
;; we use in SVGCanvas.
(class X [subclass-of Object]
  (method printElems ()
    (self do: [block (part) (part print) (space print)])))
(SequenceableCollection addAllMethodsFrom: X)

;; A String is an ordered collection that prints its elements in order
;; (i.e. like a string!)
(class String
  [subclass-of List]
  (method print ()
    (self do: [block (x) (x print)])))

(class SVGCanvas
    [subclass-of Object]
    (method startDrawing ()
      ('(<svg viewBox="-5 -5 11 10"
         width="300px" height="300px"
         transform="scale(1 -1)">) printElems)
      (newline print))

    (method stopDrawing ()
      ('</svg> println))

    (method drawPolygon: (coord-list)
	  (self LeftAsExercise))

    (method drawEllipseAt:width:height: (center w h) [locals elem]
        (set elem (Element new: 'elipse))
        (elem attribute:put: 'cx (center x))
        (elem attribute:put: 'cy (center y))
        (elem attribute:put: 'rx w)
        (elem attribute:put: 'ry h)
        (elem print))
)













;; ----- Integration test -----------------

;; Uncomment the integration test below to try drawing one of the
;; pictures in the book.

; (use /comp/105/build-prove-compare/examples/usmalltalk/shapes.smt)
; (val c (Circle new))
; (val s (Square new))
; (s adjustPoint:to: 'West (c location: 'East))
; (class Triangle
;    [subclass-of Shape]
;    ;; no additional representation
;    (method drawOn: (canvas)
;       (canvas drawPolygon: (self locations: '(North Southwest Southeast)))))
; (val t ((Triangle new) adjustPoint:to: 'Southwest (s location: 'East)))
; (val pic (Picture empty))
; (pic add: c)
; (pic add: s)
; (pic add: t)
; (val canvas (SVGCanvas new))
; '-------------------
; (begin (pic renderUsing: canvas)
;  '-------------------)