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-rw-r--r--sketch.py200
1 files changed, 128 insertions, 72 deletions
diff --git a/sketch.py b/sketch.py
index e733e9e..1ea4eb4 100644
--- a/sketch.py
+++ b/sketch.py
@@ -1,15 +1,15 @@
-class SyntaxObj(object):
- pass
-
-class EvalObj(SyntaxObj):
+class EvalObj(object):
def __str__(self):
return "#<Object>"
-class ValObj(EvalObj):
+class UnspecObj(EvalObj):
def __str__(self):
- return "#<Value>"
+ return "#<Unspecified>"
+ def ext_repr(self):
+ return self.__str__()
+
-class NumberObj(ValObj):
+class NumberObj(EvalObj):
def __str__(selfl):
return "#<Number>"
@@ -18,24 +18,35 @@ class IntObj(NumberObj):
self.val = int(num)
def __str__(self):
return "#<Integer>"
+ def ext_repr(self):
+ return str(self.val)
class FloatObj(NumberObj):
def __init__(self, num):
self.val = float(num)
def __str__(self):
return "#<Float>"
+ def ext_repr(self):
+ return str(self.val)
-class StringObj(ValObj):
+class StringObj(EvalObj):
def __init__(self, string):
self.val = string
-
def __str__(self):
return "#<String>"
-class BoolObj(ValObj):
+ def ext_repr(self):
+ return self.val
+
+class BoolObj(EvalObj):
def __init__(self, b):
self.val = b
def __str__(self):
return "#<Boolean>"
+ def ext_repr(self):
+ if self.val:
+ return "#t"
+ else:
+ return "#f"
class OptObj(EvalObj):
pass
@@ -45,32 +56,36 @@ class ProcObj(OptObj):
self.body = body
self.envt = envt
self.para_list = para_list
- def __str__(self):
+ def ext_repr(self):
return "#<Procedure>"
+ def __str__(self):
+ return self.ext_repr()
class SpecialOptObj(OptObj):
- def prepare(self, pc):
+ def prepare(self):
pass
def call(self, arg_list, pc, envt, cont):
pass
class BuiltinProcObj():
- def __init__(self, f, ext_name):
+ def __init__(self, f, name):
self.handler = f
- self.ext_name = ext_name
+ self.name = name
+ def ext_repr(self):
+ return "#<Builtin Procedure: " + self.name + ">"
def __str__(self):
- return self.ext_name
+ return self.ext_repr()
def call(self, arg_list):
return self.handler(arg_list)
def to_bool(obj):
- if obj.val == False:
+ if obj.val is False:
return BoolObj(False)
else:
return BoolObj(True)
class _builtin_if(SpecialOptObj):
- def prepare(self, pc):
+ def prepare(self):
self.state = 0 # prepare
# TODO: check number of arguments
return (True, False, False)
@@ -91,11 +106,13 @@ class _builtin_if(SpecialOptObj):
return self.pre_call(arg_list, pc, envt, cont)
else:
return self.post_call(arg_list, pc, envt, cont)
+ def ext_repr(self):
+ return "#<Builtin Macro: if>"
def __str__(self):
- return "#<builtin opt if>"
+ return self.ext_repr()
class _builtin_lambda(SpecialOptObj):
- def prepare(self, pc):
+ def prepare(self):
# TODO: check number of arguments
return (False, False)
def call(self, arg_list, pc, envt, cont):
@@ -111,14 +128,44 @@ class _builtin_lambda(SpecialOptObj):
body = pc.chd.sib
pc.chd.skip = body.skip = False
return (ProcObj(body, envt, para_list), False)
+ def ext_repr(self):
+ return "#<Builtin Macro: lambda>"
+ def __str__(self):
+ return self.ext_repr()
+
+class _builtin_define(SpecialOptObj):
+ def prepare(self):
+ # TODO: check number of arguments
+ return (False, True)
+ def call(self, arg_list, pc, envt, cont):
+ # TODO: check identifier
+ id = pc.chd.obj
+ envt.add_binding(id, arg_list[0])
+ return (UnspecObj(), False)
+ def ext_repr(self):
+ return "#<Builtin Macro: define>"
def __str__(self):
- return "#<builtin opt lambda>"
+ return self.ext_repr()
-class IdObj(SyntaxObj):
+class _builtin_set(SpecialOptObj):
+ def prepare(self):
+ # TODO: check number of arguments
+ return (False, True)
+ def call(self, arg_list, pc, envt, cont):
+ id = pc.chd.obj
+ if envt.has_obj(id):
+ envt.add_binding(id, arg_list[0])
+ return (UnspecObj(), False)
+ def ext_repr(self):
+ return "#<Builtin Macro: set!>"
+ def __str__(self):
+ return self.ext_repr()
+
+class IdObj(EvalObj):
def __init__(self, string):
self.name = string
def __str__(self):
- return "#<Identifier>"
+ return "#<Identifier: " + self.name + ">"
def get_name():
return self.name
@@ -170,8 +217,6 @@ class Node(object):
class RetAddr(object):
def __init__(self, addr):
self.addr = addr
- def get_addr(self):
- return self.addr
def __str__(self):
return "#<Return Address>"
@@ -179,7 +224,6 @@ class AbsSynTree(EvalObj):
def to_obj(self, obj):
if isinstance(obj, Node): return obj
- if obj is None: return obj
try: return IntObj(obj)
except Exception:
try: return FloatObj(obj)
@@ -187,7 +231,7 @@ class AbsSynTree(EvalObj):
def to_node(self, obj):
if isinstance(obj, Node): return obj
- return Node(self.to_obj(obj))
+ return Node(obj)
# else the obj is a string
def __init__(self, stream):
@@ -203,7 +247,7 @@ class AbsSynTree(EvalObj):
lst = stack[-1:] + lst
del stack[-1]
if len(lst) > 0:
- root = Node(self.to_obj(lst[0]))
+ root = Node(lst[0])
if len(lst) > 1:
root.chd = self.to_node(lst[1])
ref = root.chd
@@ -214,13 +258,13 @@ class AbsSynTree(EvalObj):
else:
stack[-1] = self.to_node(None)
else:
- stack.append(token)
- print stack
-
+ stack.append(self.to_obj(token))
+ for i in range(len(stack)):
+ stack[i] = self.to_node(stack[i])
self.tree = stack[0]
def is_obj(string):
- return isinstance(string, SyntaxObj)
+ return isinstance(string, EvalObj)
def is_identifier(string):
return isinstance(string, IdObj)
def is_leaf(node):
@@ -238,20 +282,29 @@ class Environment(object):
def __init__(self, prev_envt = None):
self.prev_envt = prev_envt
self.binding = dict()
- def add_binding(self, name, eval_obj):
- self.binding[name] = eval_obj
+
+ def add_binding(self, id_obj, eval_obj):
+ self.binding[id_obj.name] = eval_obj
+
+ def has_obj(self, id_obj):
+ ptr = self
+ while ptr:
+ try:
+ t = ptr.binding[id_obj.name]
+ return True
+ except KeyError:
+ ptr = ptr.prev_envt
+ return False
+
def get_obj(self, id_obj):
if is_identifier(id_obj):
ptr = self
while ptr:
try:
- t = ptr.binding[id_obj.name]
+ return ptr.binding[id_obj.name]
except KeyError:
- t = None
- if t: return t
- ptr = ptr.prev_envt
+ ptr = ptr.prev_envt
raise KeyError
-
else:
print "Not an id: " + str(id_obj)
return id_obj
@@ -301,16 +354,17 @@ def _builtin_eq(arg_list):
return BoolObj(arg_list[0].val == arg_list[1].val)
_default_mapping = {
- "+" : BuiltinProcObj(_builtin_plus, "builtin proc +"),
- "-" : BuiltinProcObj(_builtin_minus, "builtin proc -"),
- "*" : BuiltinProcObj(_builtin_times, "builtin proc *"),
- "/" : BuiltinProcObj(_builtin_div, "builtin proc /"),
- "<" : BuiltinProcObj(_builtin_lt, "builtin proc <"),
- ">" : BuiltinProcObj(_builtin_gt, "builtin proc >"),
- "=" : BuiltinProcObj(_builtin_eq, "builtin proc ="),
- "lambda" : _builtin_lambda(),
- "if" : _builtin_if()
- }
+ IdObj("+") : BuiltinProcObj(_builtin_plus, "+"),
+ IdObj("-") : BuiltinProcObj(_builtin_minus, "-"),
+ IdObj("*") : BuiltinProcObj(_builtin_times, "*"),
+ IdObj("/") : BuiltinProcObj(_builtin_div, "/"),
+ IdObj("<") : BuiltinProcObj(_builtin_lt, "<"),
+ IdObj(">") : BuiltinProcObj(_builtin_gt, ">"),
+ IdObj("=") : BuiltinProcObj(_builtin_eq, "="),
+ IdObj("lambda") : _builtin_lambda(),
+ IdObj("if") : _builtin_if(),
+ IdObj("define") : _builtin_define(),
+ IdObj("set!") : _builtin_set()}
class Evaluator(object):
@@ -359,20 +413,23 @@ class Evaluator(object):
def push(pc, top, otop):
ntop = top
notop = otop
- pc.print_()
if is_leaf(pc):
print "first"
ntop += 1
- stack[ntop] = envt.get_obj(pc.obj)
+ if pc.skip:
+ new_obj = pc.obj
+ else:
+ new_obj = envt.get_obj(pc.obj)
+ stack[ntop] = new_obj
npc = pc.sib
pc.print_()
- print "this val is: " + str(stack[ntop].val)
+ #print "this val is: " + str(stack[ntop].val)
else:
print "second"
ntop += 1
stack[ntop] = RetAddr(pc) # Return address
if isinstance(pc.obj, Node):
- print "Operand need to be resolved!"
+ print "Operator need to be resolved!"
notop += 1
ostack[notop] = pc
notop += 1
@@ -380,11 +437,11 @@ class Evaluator(object):
pc.obj.print_() # Step in to resolve operator
npc = pc.obj
else:
- print "Getting operand: " + str(pc.obj.name)
+ print "Getting operator: " + str(pc.obj.name)
ntop += 1
stack[ntop] = envt.get_obj(pc.obj)
if is_special_opt(stack[ntop]):
- mask = stack[ntop].prepare(pc)
+ mask = stack[ntop].prepare()
mask_eval(pc, mask)
npc = pc.chd
return (npc, ntop, notop)
@@ -404,7 +461,7 @@ class Evaluator(object):
if pc is None:
if top > 0 and is_ret_addr(stack[top - 1]) and \
- stack[top - 1].get_addr() is False:
+ stack[top - 1].addr is False:
stack[top - 1] = stack[top]
top -= 1
envt = cont.envt
@@ -421,7 +478,7 @@ class Evaluator(object):
# Top is now pointing to the return address
print "Arg List: " + str(arg_list)
opt = arg_list[0]
- ret_addr = stack[top].get_addr()
+ ret_addr = stack[top].addr
if is_builtin_proc(opt): # Built-in Procedures
print "builtin"
@@ -445,7 +502,7 @@ class Evaluator(object):
envt = Environment(opt.envt) # New ENV and recover the closure
#TODO: Compare the arguments to the parameters
for i in xrange(1, len(arg_list)):
- envt.add_binding(opt.para_list[i - 1].name,
+ envt.add_binding(opt.para_list[i - 1],
arg_list[i]) # Create bindings
stack[top] = RetAddr(False) # Mark the exit of the continuation
pc = opt.body # Get to the entry point
@@ -460,20 +517,19 @@ class Evaluator(object):
print " Done...\n"
return stack[0]
-import pdb
t = Tokenizor()
e = Evaluator()
-e.envt.add_binding("x", IntObj(100))
-#t.feed("(+ (- (* 10 2) (+ x 4)) (+ 1 2) (/ 25 5))")
-#t.feed("(if (> 2 2) (if (> 2 1) 1 2) 3)")
-t.feed("((lambda (x y) ((lambda (z) (+ z (* x y))) 10)) ((lambda (x y) (+ x y)) 3 2) 4)")
-#t.feed("(lambda (x y) (* x x))")
-a = AbsSynTree(t)
-#a.tree.print_()
-#a.tree.obj.print_()
-print e.run_expr(a).val
-##t.feed("((lambda (x) (x * x)) 2)")
-#a = AbsSynTree(t)
-#print e.run_expr(a).val
-#a = AbsSynTree(t)
-#print e.run_expr(a).val
+
+import sys, pdb
+
+#ins_set = ("(define x 1)", "(set! x 3)")
+#for ins in ins_set:
+# print "TEST"
+# t.feed(ins)
+# print "Output: " + e.run_expr(AbsSynTree(t)).ext_repr()
+#
+while True:
+ sys.stdout.write("Syasi> ")
+ cmd = sys.stdin.readline()
+ t.feed(cmd)
+ print e.run_expr(AbsSynTree(t)).ext_repr()