def parse_declaration(self) -> list:
# Int thing
# Int thing = expr
# TODO: module.Thingy thing
#
# "Int thing = expr" produces overlapping Declaration and
# Assignment nodes, that's why this returns a list of nodes
datatype = self.parse_name() # TODO: module's Thing
variable = self.parse_name()
if self.tokens.coming_up().kind == 'NEWLINE':
self.tokens.pop_newline()
return [
Declaration(Location.between(datatype, variable), datatype,
variable.name)
]
self.tokens.check_and_pop('OP', '=')
initial_value = self.parse_expression()
self.tokens.pop_newline()
return [
Declaration(Location.between(datatype, variable), datatype,
variable.name),
Assignment(Location.between(variable, initial_value), variable,
initial_value)
]
def parse_function_def(self):
# function main() { ... }
# function thing() returns Int { ... }
function_keyword = self.tokens.check_and_pop('NAME', 'function')
name = self.parse_name()
args, junk = self._parse_comma_list('(',
')',
parsemethod=self._type_and_name)
if self.tokens.coming_up().startswith(['NAME', 'returns']):
self.tokens.pop()
returntype = self.parse_name()
else:
returntype = None
opening_brace = self.tokens.check_and_pop('OP', '{')
if self.tokens.coming_up().kind == 'NEWLINE':
self.tokens.pop_newline()
body = []
while not self.tokens.coming_up().startswith(['OP', '}']):
body.extend(self.parse_statement())
closing_brace = self.tokens.check_and_pop('OP', '}')
self.tokens.pop_newline()
return FunctionDef(Location.between(function_keyword, closing_brace),
name.name, args, returntype, body)
def parse_expression(self):
coming_up = self.tokens.coming_up()
if coming_up.kind == 'NAME':
# hello
result = self.parse_name()
elif coming_up.kind == 'STRING':
# "hello"
result = self.parse_string()
elif coming_up.kind == 'INTEGER':
# 123
result = self.parse_integer()
elif coming_up.startswith(['OP', '(']):
result = self.parse_parentheses()
else:
raise CompileError(
"this should be variable name, string, integer or '('",
coming_up.location)
# check for function calls, this is a while loop to allow
# function calls like thing()()()
while self.tokens.coming_up().startswith(['OP', '(']):
args, stop_token = self._parse_comma_list('(', ')')
result = FunctionCall(Location.between(result, stop_token), result,
args)
return result
def _parse_comma_list(self, start='(', stop=')', parsemethod=None):
# ( )
# ( element )
# ( element , )
# ( element , element )
# ( element , element , )
# ...
if parsemethod is None:
parsemethod = self.parse_expression
start_token = self.tokens.check_and_pop('OP', start)
if self.tokens.coming_up().startswith(['OP', stop]):
# empty list
return ([], self.tokens.pop())
elements = []
while True:
if self.tokens.coming_up().startswith(['OP', ',']):
raise CompileError("don't put a ',' here",
self.tokens.coming_up().location)
elements.append(parsemethod())
if self.tokens.coming_up().startswith(['OP', stop]):
return (elements, self.tokens.pop())
comma = self.tokens.check_and_pop('OP', ',')
if self.tokens.coming_up().startswith(['OP', ',']):
raise CompileError(
"two ',' characters",
Location.between(comma, self.tokens.coming_up()))
if self.tokens.coming_up().startswith(['OP', stop]):
return (elements, self.tokens.pop())
def assignment(self):
# thing = value
# TODO: thing's stuff = value
target = self.parse_name()
self.tokens.check_and_pop('OP', '=')
value = self.parse_expression()
self.tokens.pop_newline()
return Assignment(Location.between(target, value), target, value)
def parse_if(self):
# if cond { statements }
the_if = self.tokens.check_and_pop('NAME', 'if')
condition = self.parse_expression()
self.tokens.check_and_pop('OP', '{')
body = []
# allow "if thing { }" without a newline
if not self.tokens.coming_up().startswith(['OP', '}']):
self.tokens.pop_newline()
while not self.tokens.coming_up().startswith(['OP', '}']):
body.extend(self.parse_statement())
closing_brace = self.tokens.check_and_pop('OP', '}')
self.tokens.pop_newline()
return If(Location.between(the_if, closing_brace), condition, body)
def parse_return(self):
the_return = self.tokens.check_and_pop('NAME', 'return')
value = self.parse_expression()
self.tokens.pop_newline()
return Return(Location.between(the_return, value), value)