python examples added

python/draw.py

@@ -0,0 +1,193 @@
+# drawing figures with natural language commands
+# presupposes 'gf -make DrawEng.gf (DrawSwe.gf ...)'
+
+import pgf
+from graphics import *
+import sys
+from random import randrange
+
+# we assume this abstract syntax
+absmodule = "Draw"
+
+# change this to change input language
+langname = absmodule + "Eng"
+
+# the size of canvas
+hsize, vsize = 1000,1000
+
+# the mid point of the canvas
+midpoint = (hsize/2,vsize/2)
+
+# unit size granularity
+sizeunit = hsize//10
+
+# big and small size factors
+bigsize = 2
+smallsize = 0.2
+
+# limits of radius and diameter/2
+maxradius = sizeunit
+minradius = sizeunit/2
+
+# distance of movement
+distunit = 2*sizeunit
+
+def execute(command,win):
+  "top level: execute a Command in a window (given in main)"
+  fun,args = command.unpack()
+
+  if fun == "drawCommand":
+    obj = shape(args[0])
+    obj.draw(win)
+    return str(args[0]),obj,fun
+
+  if fun == "removeCommand":
+    key = reference(args[0])
+    return key,None,fun
+  
+  if fun == "moveCommand":
+    key = reference(args[0])
+    return key,direction(args[1]),fun
+
+def reference(objectref):
+  fun,args = objectref.unpack()
+  if fun == "theObjectRef":
+    return(str(args[0]))
+  else:
+    return(str(objectref))
+
+def shape(obj):
+  "draw a Shape of random size and position, possibly with colour and rough size specified"
+  fun,args = obj.unpack()
+
+  sz,xx = args[0].unpack()
+  if sz == "big_Size":
+    factor = bigsize
+  elif sz == "small_Size":
+    factor = smallsize
+  else:
+    factor = 1
+    
+  midx,midy = midpoint
+  x1 = midx + randrange(-midx,midx,1)
+  y1 = midy + randrange(-midy,midy,1)
+  r  = factor * randrange(minradius, maxradius, 1)
+  d  = 2 * r
+  x2 = x1 + d
+  y2 = y1 + d
+  sh,xx = args[2].unpack()
+  if sh == "circle_Shape":
+    shap = Circle(Point(x1,y1),r)
+  elif sh == "square_Shape":
+    shap = Rectangle(Point(x1,y1),Point(x2,y2))
+  else:
+    shap = None
+
+  co,xx = args[1].unpack()
+  if co == "green_Colour":
+    shap.setFill('green')
+  elif co == "red_Colour":
+    shap.setFill('red')
+  elif co == "blue_Colour":
+    shap.setFill('blue')
+  elif co == "yellow_Colour":
+    shap.setFill('yellow')
+  else:
+    pass
+    
+  return shap
+
+def direction(place):
+  fun,args = place.unpack()
+  if fun == "upPlace":
+    return 0,-distunit
+  if fun == "downPlace":
+    return 0,distunit
+  if fun == "leftPlace":
+    return -distunit,0
+  if fun == "rightPlace":
+    return distunit,0
+  else:
+    return randrange(-2*distunit,2*distunit,1),randrange(-2*distunit,2*distunit,1)
+
+def addRef(ref,obj,refs):
+    "adds a reference and object to the top of the stack"
+    return [(ref,obj)] + refs
+
+def lookupRef(ref,refs):
+    "return the first value and index of ref in a list of pairs refs"
+    i = 0
+    for ro in refs:
+        r,obj = ro
+        if matchRef(ref,r):
+            return r,obj,i
+        else:
+            i = i + 1
+    return None,None,None
+
+def removeRef(ref,refs):
+    "remove the first pair matching ref in refs"
+    r,obj,i = lookupRef(ref,refs)
+    refs.pop(i)
+    return refs
+
+def matchRef(ref,r):
+    if ref == "itObjectRef":
+        return True
+    else:
+        refws = ref.split()
+        rws = r.split()
+        m = True
+        for i in range(1,4):
+          if (refws[i][0:2] != "no") and (refws[i] != rws[i]):
+              return False
+        return m
+
+def main():
+  "initialize with a window, process Command input line by line; optional language argument"
+  win = GraphWin("GF Draw", hsize, vsize)
+  refs = []
+  latest = "it"
+  gr  = pgf.readPGF(absmodule + ".pgf")
+  lang = langname
+  if len(sys.argv) > 1:
+    lang = absmodule + sys.argv[1]
+  eng = gr.languages[lang]
+  while True:
+      try:
+          line = input("")
+      except EOFError:
+          break
+      if not(line):
+          pass
+      else:
+          try:
+              px = eng.parse(line.lower())
+              p,tree = px.__next__()
+              key,obj,co = execute(tree,win)
+              if co == "drawCommand":
+                  refs = addRef(key,obj,refs)
+              elif co == "removeCommand":
+                  ref,sh,i = lookupRef(key,refs)
+                  if sh is None:
+                    print("no such object")
+                  else:
+                    sh.undraw()
+                    refs = removeRef(key,refs)
+              elif co == "moveCommand":
+                  x,y = obj
+                  ref,sh,i = lookupRef(key,refs)
+                  if sh is None:
+                    print("no such object")
+                  else:
+                    sh.move(x,y)
+                    refs = [(ref,sh)] + refs[:i] + refs[i+1:]
+              else:
+                  print("nothing else can be done")
+              print(refs) ## debugging
+          except pgf.ParseError:
+              print("# NO PARSE", line)
+
+main()
+
+