def special_local(self, greedy):
"""
The special LOCAL form (with unevaluated variables). (Should
this be generally greedy?)
"""
vars = []
if greedy:
while 1:
tok = self.tokenizer.peek()
if tok in (':', '"'):
self.tokenizer.next()
continue
elif not reader.is_word(tok):
break
vars.append(tok)
self.tokenizer.next()
else:
if self.tokenizer.peek() in (':', '"'):
self.tokenizer.next()
vars = [self.tokenizer.next()]
for v in vars:
self.make_local(v)
return None
def special_local(self, greedy):
"""
The special LOCAL form (with unevaluated variables). (Should
this be generally greedy?)
"""
vars = []
if greedy:
while 1:
tok = self.tokenizer.peek()
if tok in (':', '"'):
self.tokenizer.next()
continue
elif not reader.is_word(tok):
break
vars.append(tok)
self.tokenizer.next()
else:
if self.tokenizer.peek() in (':', '"'):
self.tokenizer.next()
vars = [self.tokenizer.next()]
for v in vars:
self.make_local(v)
return None
def expr_inner(self, apply=None, get_function=None, get_variable=None):
"""
An 'inner' expression, an expression that does not include
infix operators.
::
exprInner ::= <literal int or float>
::= '-' expr
::= '+' expr
::= ('\"' or 'QUOTE') <word>
::= ':' <word>
::= MAKE (':' or '\"') <word> expr
::= MAKE <word> expr
::= TO <to expression>
::= '[' <list expression> ']'
::= '(' <word> <expr> ... <expr> ')'
::= <word> <expr> ... <expr>
Things to note:
* ``MAKE :x 10``, ``MAKE \"x 10``, and ``MAKE x 10`` all work
equivalently (make is a special form, unlike in UCBLogo).
* <list expression> is a nested list of tokens.
* <to expression> is TO func_name var1 var2 <int>, where <int>
is the default arity (number of variables). Variables, like
with make, can be prefixed with : or \", but need not be.
* () is not used to force precedence, but to force execution
with a specific arity. In other words, () works like Lisp.
"""
tok = self.tokenizer.next()
if apply is None:
apply = self.apply
if get_function is None:
get_function = self.get_function
if get_variable is None:
get_variable = self.get_variable
if tok == '\n':
raise LogoEndOfLine("The end of the line was not expected")
return self.expr_inner()
elif tok is EOF:
raise LogoEndOfCode("The end of the code block was not expected")
elif not isinstance(tok, basestring):
# Some other fundamental type (usually int or float)
return tok
elif tok == '-':
# This works really poorly in practice, because "-" usually
# gets interpreted as an infix operator.
return -self.expr()
elif tok == '+':
return self.expr()
elif tok in ('/', '*'):
raise LogoError("Operator not expected: %s" % tok)
elif tok == '"' or tok.lower() == 'quote':
tok = self.tokenizer.next()
return tok
elif tok == ':':
tok = self.tokenizer.next()
return get_variable(tok)
elif tok == '[':
self.tokenizer.push_context('[')
result = self.expr_list()
self.tokenizer.pop_context()
return result
elif tok == ';':
while 1:
tok = self.tokenizer.next()
if tok == '\n' or tok is EOF:
break
elif tok == '(':
self.tokenizer.push_context('(')
try:
func = self.tokenizer.peek()
if not reader.is_word(func):
# We don't actually have a function call then, but
# just a sub-expression.
val = self.expr()
if not self.tokenizer.next() == ')':
raise LogoSyntaxError("')' expected")
return val
else:
self.tokenizer.next()
if func.lower() in self.special_forms:
special_form = self.special_forms[func.lower()]
val = special_form(self, greedy=True)
next_tok = self.tokenizer.next()
if next_tok != ')':
raise LogoSyntaxError("')' expected")
return val
else:
args = []
while 1:
tok = self.tokenizer.peek()
if tok == ')':
break
elif tok == '\n':
self.tokenizer.next()
continue
elif tok is EOF:
raise LogoEndOfCode(
"Unexpected end of code (')' expected)")
args.append(self.expr())
val = apply(get_function(func), args)
if not self.tokenizer.next() == ')':
raise LogoSyntaxError("')' was expected.")
finally:
self.tokenizer.pop_context()
return val
else:
if not reader.is_word(tok):
raise LogoSyntaxError("Unknown token: %r" % tok)
if tok.lower() in self.special_forms:
special_form = self.special_forms[tok.lower()]
val = special_form(self, greedy=False)
return val
else:
func_name = tok
func = get_function(func_name)
n = arity(func)
self.tokenizer.push_context('func')
try:
args = []
# -1 arity means the function is greedy
if n == -1:
while 1:
tok = self.tokenizer.peek()
if tok == '\n' or tok is EOF:
self.tokenizer.next()
break
args.append(self.expr())
else:
for i in range(n):
try:
args.append(self.expr())
except (LogoEndOfCode, LogoEndOfLine):
raise LogoEndOfCode(
"Not enough arguments provided to %s: got %i and need %i"
% (func_name, i, n))
finally:
self.tokenizer.pop_context()
return apply(func, args)
def expr_inner(self, apply=None, get_function=None,
get_variable=None):
"""
An 'inner' expression, an expression that does not include
infix operators.
::
exprInner ::= <literal int or float>
::= '-' expr
::= '+' expr
::= ('\"' or 'QUOTE') <word>
::= ':' <word>
::= MAKE (':' or '\"') <word> expr
::= MAKE <word> expr
::= TO <to expression>
::= '[' <list expression> ']'
::= '(' <word> <expr> ... <expr> ')'
::= <word> <expr> ... <expr>
Things to note:
* ``MAKE :x 10``, ``MAKE \"x 10``, and ``MAKE x 10`` all work
equivalently (make is a special form, unlike in UCBLogo).
* <list expression> is a nested list of tokens.
* <to expression> is TO func_name var1 var2 <int>, where <int>
is the default arity (number of variables). Variables, like
with make, can be prefixed with : or \", but need not be.
* () is not used to force precedence, but to force execution
with a specific arity. In other words, () works like Lisp.
"""
tok = self.tokenizer.next()
if apply is None:
apply = self.apply
if get_function is None:
get_function = self.get_function
if get_variable is None:
get_variable = self.get_variable
if tok == '\n':
raise LogoEndOfLine("The end of the line was not expected")
return self.expr_inner()
elif tok is EOF:
raise LogoEndOfCode("The end of the code block was not expected")
elif not isinstance(tok, basestring):
# Some other fundamental type (usually int or float)
return tok
elif tok == '-':
# This works really poorly in practice, because "-" usually
# gets interpreted as an infix operator.
return -self.expr()
elif tok == '+':
return self.expr()
elif tok in ('/', '*'):
raise LogoError("Operator not expected: %s" % tok)
elif tok == '"' or tok == 'quote':
tok = self.tokenizer.next()
return tok
elif tok == ':':
tok = self.tokenizer.next()
return get_variable(tok)
elif tok == '[':
self.tokenizer.push_context('[')
result = self.expr_list()
self.tokenizer.pop_context()
return result
elif tok == ';':
while 1:
tok = self.tokenizer.next()
if tok == '\n' or tok is EOF:
break
elif tok == '(':
self.tokenizer.push_context('(')
try:
func = self.tokenizer.peek()
if not reader.is_word(func):
# We don't actually have a function call then, but
# just a sub-expression.
val = self.expr()
if not self.tokenizer.next() == ')':
raise LogoSyntaxError("')' expected")
return val
else:
self.tokenizer.next()
if self.special_forms.has_key(func):
special_form = self.special_forms[func]
val = special_form(self, greedy=True)
next_tok = self.tokenizer.next()
if next_tok != ')':
raise LogoSyntaxError("')' expected")
return val
else:
args = []
while 1:
tok = self.tokenizer.peek()
if tok == ')':
break
elif tok == '\n':
self.tokenizer.next()
continue
elif tok is EOF:
raise LogoEndOfCode("Unexpected end of code (')' expected)")
args.append(self.expr())
val = apply(get_function(func), args)
if not self.tokenizer.next() == ')':
raise LogoSyntaxError("')' was expected.")
finally:
self.tokenizer.pop_context()
return val
else:
if not reader.is_word(tok):
raise LogoSyntaxError("Unknown token: %r" % tok)
if tok in self.special_forms:
special_form = self.special_forms[tok]
val = special_form(self, greedy=False)
return val
else:
func_name = tok
func = get_function(func_name)
n = arity(func)
self.tokenizer.push_context('func')
try:
args = []
# -1 arity means the function is greedy
if n == -1:
while 1:
tok = self.tokenizer.peek()
if tok == '\n' or tok is EOF:
self.tokenizer.next()
break
args.append(self.expr())
else:
for i in range(n):
try:
args.append(self.expr())
except (LogoEndOfCode, LogoEndOfLine):
raise LogoEndOfCode(
"Not enough arguments provided to %s: got %i and need %i" % (func_name, i, n))
finally:
self.tokenizer.pop_context()
return apply(func, args)
