def insert(self, variable, value, env_list): """ Inserts a new variable with the specified value into the specified environment. Parameters: variable -- A VARIABLE type Lexeme object with the variable's name as its value. value -- A NUMBER, BOOLEAN, or STRING type Lexeme object with the variable's value as its value. env_list -- The Environment list into which to insert the variable. """ if self._debug: print( "Inserting variable [" + str(variable) + "]") if self._debug: print( " with value [" + str(value) + "].") var_glue = Lexeme(token_type="GLUE", left=variable) val_glue = Lexeme(token_type="GLUE", left=value) head = env_list.left var_glue.right = head.left val_glue.right = head.right head.left = var_glue head.right = val_glue
def booleanExpression(self):
tree = Lexeme(token_type="BOOLEAN_EXPRESSION")
tmp = Lexeme(token_type="GLUE")
tmp.left = self.expression()
self.match("IS")
tree.left = self.boolOp()
tmp.right = self.expression()
tree.right = tmp
return tree
def ifStatement(self):
if self._debug: print(" in ifStatement")
self.match("IF")
tree = Lexeme(token_type="IF_STATEMENT")
tmp = Lexeme(token_type="GLUE")
tree.left = self.booleanExpression()
self.match("COMMA")
tmp.left = self.block()
tmp.right = self.optOtherwise()
tree.right = tmp
return tree
def statements(self):
if self._debug: print(" in statements")
tree = Lexeme(token_type="STATEMENTS")
tree.left = self.statement()
tree.right = self.optStatements()
return tree
def commaChain(self):
if self._debug: print(" in commaChain")
self.match("COMMA")
tree = Lexeme(token_type="GLUE")
tree.left = self.expression()
tree.right = self.optCommaChain()
return tree
def whileStatement(self):
if self._debug: print(" in whileStatement")
self.match("WHILE")
tree = Lexeme(token_type="WHILE_STATEMENT")
tree.left = self.booleanExpression()
self.match("COMMA")
tree.right = self.block()
return tree
def assignment(self):
if self._debug: print(" in assignment")
self.match("SET")
tree = Lexeme(token_type="ASSIGNMENT")
tree.left = self.match("VARIABLE")
self.match("TO")
tree.right = self.expression()
self.match("PERIOD")
return tree
def sequence(self):
if self._debug: print(" in sequence")
tree = Lexeme(token_type="GLUE") # this will be attached to the "head" in my environment
tree.left = self.expression()
if self.check("AND"):
self.match("AND")
tmp = Lexeme(token_type="GLUE")
tmp.left = self.expression()
tree.right = tmp
elif self.commaChainPending():
tmp = self.commaChain()
self.match("AND")
tracer = tmp
while tracer.right:
tracer = tracer.right
tracer.left = self.expression()
tree.right = tmp
return tree
def optCommaChain(self):
if self._debug: print(" in optCommaChain")
tree = None
if self.check("COMMA"):
tree = Lexeme(token_type="GLUE")
self.match("COMMA")
if self.expressionPending():
tree.left = self.expression()
tree.right = self.optCommaChain()
return tree
def sequence(self):
if self._debug: print(" in sequence")
tree = Lexeme(token_type="LIST")
tree.left = self.expression()
if self.check("AND"):
self.match("AND")
tmp = Lexeme(token_type="GLUE")
tmp.left = self.expression()
tree.right = tmp
elif self.commaChainPending():
tmp = self.commaChain()
self.match("AND")
tracer = tmp
while tracer.right:
tracer = tracer.right
tmp2 = Lexeme(token_type="GLUE")
tmp2.left = self.expression()
tracer.right = tmp2
tree.right = tmp
return tree
def program(self):
if self._debug: print(" in program")
tree = Lexeme(token_type="PROGRAM")
sections = []
while self.functionDefPending() or self.statementsPending():
if self.functionDefPending():
sections.append(self.functionDef())
if self.statementsPending():
sections.append(self.statements())
self.match("EOF")
tmp = Lexeme(token_type="GLUE")
tracer = tmp
for section in sections:
tracer.left = section
tracer.right = Lexeme(token_type="GLUE")
tracer = tracer.right
tree.right = tmp
return tree
