class Assign:
def __init__(self):
self.id = None
self.expr = None
#Simple parsing for Assign
def parse(self):
self.id = Id()
self.id.parse(TokList.getIdOrConst())
TokList.nextToken()
TokList.match('ASSIGN', 'assign')
self.expr = Expr()
self.expr.parse()
TokList.match('SEMICOLON', 'assign')
#Simple printing for Assign
def print(self):
TokList.printIndent()
self.id.print()
print(':=', end='')
self.expr.print()
print(';')
#Executor that determines value of an expression and then sets that value to the respective Id
def exec(self):
val = self.expr.exec()
self.id.setValue(val)
class CaseLine:
def __init__(self):
self.const = None
self.constList = None
self.expr = None
self.caseLineFollow = None
#Parsing for CaseLine based on the homework
def parse(self):
self.const = Const()
self.const.parse(TokList.getIdOrConst())
TokList.nextToken()
if TokList.currentToken() == 'COMMA':
self.constList = ConstList()
self.constList.parse()
TokList.match('COLON', 'case line')
self.expr = Expr()
self.expr.parse()
self.caseLineFollow = CaseLineFollow()
self.caseLineFollow.parse()
#Simple printing
def print(self):
self.const.print()
if self.constList is not None:
self.constList.print()
print(':', end='')
self.expr.print()
self.caseLineFollow.print()
#Exectuion that returns a boolean based on idValue and constants given
def exec(self, caseId):
if self.const.exec() == caseId.getValue():
caseId.setValue(self.expr.exec())
return True
if self.constList is not None:
if self.constList.exec(caseId):
caseId.setValue(self.expr.exec())
return True
if self.caseLineFollow.exec(caseId):
return True
return False
class Case:
def __init__(self):
self.case_line = None
self.expr = None
self.id = None
#Simple parse of the case statement
def parse(self):
TokList.match('CASE','case')
self.id = Id()
self.id.parse(TokList.getIdOrConst())
TokList.nextToken()
TokList.match('OF','case')
self.case_line = CaseLine()
self.case_line.parse()
TokList.match('ELSE','case')
self.expr = Expr()
self.expr.parse()
TokList.match('END','case')
TokList.match('SEMICOLON','case')
#Printing with proper indentation manipulation and new line printings
def print(self):
TokList.printIndent()
print('case ', end='')
self.id.print()
print(' of')
TokList.increaseIndent()
TokList.printIndent()
self.case_line.print()
#Necessary for new line printings
print()
TokList.printIndent()
print('else ', end='')
self.expr.print()
print()
TokList.decreaseIndent()
TokList.printIndent()
print('end;')
#Recursive execution based on values in the case line. Id value is passed in to all versions of case
def exec(self):
if not (self.case_line.exec(self.id)):
self.id.setValue(self.expr.exec())
class Out:
def __init__(self):
self.expr = None
#Simple parsing for output statement
def parse(self):
TokList.match('OUTPUT', 'output')
self.expr = Expr()
self.expr.parse()
TokList.match('SEMICOLON', 'output')
#Simple printing
def print(self):
TokList.printIndent()
print('output ', end='')
self.expr.print()
print(';')
#Execution that prints the values returned by the expression evaluation
def exec(self):
print(self.expr.exec())
class Cmpr:
def __init__(self):
self.rightExpr = None
self.leftExpr = None
self.checkValue = None
#Parsing to determine kind of comparator. Checks for middle comparison while returning an error if none are given.
def parse(self):
self.leftExpr = Expr()
self.leftExpr.parse()
if TokList.checkTok('EQUAL'):
self.checkValue = '='
TokList.nextToken()
elif TokList.checkTok('LESSTHAN'):
self.checkValue = '<'
TokList.nextToken()
elif TokList.checkTok('LESSTHANEQUAL'):
self.checkValue = '<='
TokList.nextToken()
else:
print('Error: improper syntax for comparator')
exit()
self.rightExpr = Expr()
self.rightExpr.parse()
#Simple printing
def print(self):
self.leftExpr.print()
print(self.checkValue, end='')
self.rightExpr.print()
#Executor based on results gained while parsing
def exec(self):
if self.checkValue == '=':
return self.leftExpr.exec() == self.rightExpr.exec()
elif self.checkValue == '<':
return self.leftExpr.exec() < self.rightExpr.exec()
elif self.checkValue == '<=':
return self.leftExpr.exec() <= self.rightExpr.exec()
