diff options
| -rw-r--r-- | sketch.py | 200 |
1 files changed, 128 insertions, 72 deletions
@@ -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() |