def load_const(stream):
tag = stream.read(1)
if tag == K_SYMBOL:
return make_symbol(load_string(stream))
elif tag == K_FIXNUM:
return W_Fixnum(load_number(stream))
elif tag == K_PAIR:
# XXX: recursive call -- stack overflow?
car = load_const(stream)
cdr = load_const(stream)
return W_Pair(car, cdr)
elif tag == K_NULL:
return w_nil
elif tag == K_TRUE:
return make_bool(True)
elif tag == K_FALSE:
return make_bool(False)
elif tag == K_UNSPEC:
return w_unspecified
else:
raise ValueError('unknown tag -- %s' % tag)
import __pypy_path__
from pypy.rlib.parsing.makepackrat import PackratParser, BacktrackException, Status
from sanya.objectmodel import make_symbol, W_Pair, W_Fixnum, w_nil, make_bool
def parse_string(code_string):
""" Parse a string and return a sexpression.
"""
p = MyParser(code_string)
return p.prog()
# ____________________________________________________________________________
# implementation details.
quote_symbol = make_symbol("quote")
def make_quote(sexpr):
return W_Pair(quote_symbol, W_Pair(sexpr, w_nil))
class MyParser(PackratParser):
r"""
SYMBOL:
c = `[\+\-\*\^\?a-zA-Z!<=>_~/$%&:][\+\-\*\^\?a-zA-Z0-9!<=>_~/$%&:]*`
IGNORE*
return {make_symbol(c)};
BOOLEAN:
c = `#(t|f)`
def make_cont_hole(self):
w_cont = self.make_cont_closure()
w_retsym = make_symbol(arg_counter.get())
return ContHole(w_cont, w_retsym)
if not prev_cont:
outer_cont = prev_cont = walker.visit(expr).make_cont_hole()
else:
curr_cont = walker.visit(expr).make_cont_hole()
prev_cont.set_hole(curr_cont.make_cont_closure())
prev_cont = curr_cont
prev_cont.set_hole(cont_s)
return outer_cont.make_cont_closure()
# ________________________________________________________________________
# implementation details
class CPSTransformError(Exception):
pass
lambda_s = make_symbol('lambda')
cont_s = make_symbol('cont')
display_s = make_symbol('display')
class Counter(object):
def __init__(self, prefix=""):
self.prefix = prefix
self.count = 0
def get(self):
res = self.prefix + str(self.count)
self.count += 1
return res
arg_counter = Counter('cps-t-')