def visitStatement(self, ctx: DecafParser.StatementContext):
#Rule 17 iterate through the expressions found within a for loop and check if they are digits by using a python built in feature, if not then the for loop is not valid and error displayed
if ctx.FOR():
for j, i in enumerate(ctx.expr()):
if i.getText().isdigit() != True:
#Tell us which expr has the issue 0 = first 1 = second
print("[Rule 17] Expected type int for expr", j , "in this for loop but found error on line:", ctx.start.line, "is int?", i.getText().isdigit())
#Rule 11 check if boolean has return in body! if not error out, simple check for a true or false within the statement
if ctx.IF():
temp = ctx.getText()
if temp.find('true') == -1 and temp.find('false') == -1:
print('[Rule 11] error on line', ctx.start.line, 'expected boolean type return value')
# rule 2, No identifier is used before it is declared, check if it exists in the symbol table, this rule was provided by Ryan via screencast on moodle
if ctx.location():
id = ctx.location().ID().getText()
if (self.st.lookup(id) == None):
print("[Rule 2] error on line", ctx.start.line,'ID: (', id, ') not declared before use')
if ctx.location():
if ctx.location().ID().getText() != None:
if self.st.lookup(ctx.location().ID().getText()) == None:
print('[Rule 9] error ID (', ctx.location().ID().getText(), ") does not exists in local/global variable or formal parameter, on line", ctx.start.line)
#Rule 15 check that location and expr have the same type by doing a lookup in the table if they exist if they do then test to see if types match otherwise
#error and error if not in symbol table
if ctx.location() and ctx.expr():
lookup = self.st.lookup(ctx.location().getText())
for i in ctx.expr():
res = self.st.lookup(i.getText())
if lookup == None and res == None or lookup and res and lookup.type != res.type:
print("[Rule 15] location and expr don't have same type")
return self.visitChildren(ctx)
def visitStatement(self, ctx: DecafParser.StatementContext):
line_num = ctx.start.line
expression = ctx.expr(0)
# 11 Expr of an if must have type bool
if ctx.IF() != None:
expr_type = self.visit(expression)
expr_b_type = self.visit(expression.expr(0))
print(expr_b_type)
#if (expr_a_type != None and expr_a_type != 'boolean') or (expr_b_type != None and expr_b_type != 'boolean'):
#print('Error on line ' + str(line_num) + ', expression in if must be of type boolean')
elif ctx.location() != None:
loc_type = self.visit(ctx.location())
expr_type = self.visit(ctx.expr(0))
operator = ctx.assign_op().getText()
identifier = self.st.probe(ctx.location().getText())
#2
if identifier == None:
print('Error on line ' + str(line_num) + ', identifier \'' +
ctx.location().getText() + '\' has not been declared')
#16 - TODO change error message
elif loc_type != None:
if (loc_type != 'int'
or expr_type != 'int') and (operator == '-='
or operator == '+='):
print(
'Error on line ' + str(line_num) +
' variables must be of type int when in an incrementing/decrementing assignment'
)
#15
elif loc_type != expr_type:
print('Error on line ' + str(line_num) +
' type mismatched in expression')
#17
elif ctx.FOR() != None:
expr_type_a = self.visit(ctx.expr(0))
expr_type_b = self.visit(ctx.expr(1))
if expr_type_a != 'int' or expr_type_b != 'int':
print('Error on line ' + str(line_num) +
' for statement expressions must be of type int')
else:
self.visitChildren(ctx)
def visitStatement(self, ctx:DecafParser.StatementContext):
if ctx.CONTINUE() != None:
self.body += '\tjmp main\n'
if ctx.BREAK() != None:
self.body += '\tjmp main\n'
if ctx.IF():
self.st.enterScope()
if_label = 'if-label-'+str(self.IF_LABEL_COUNT)
self.body += '\tcmp %r11 %r10\n'
self.body += '\tjl '+if_label+'l\n'
self.body += '\tje '+if_label+'e\n'
self.body += '\tjg '+if_label+'g\n'
self.body += '\tret\n'
self.body += if_label+':\n'
self.IF_LABEL_COUNT = self.IF_LABEL_COUNT + 1
ctx.expr()
self.st.exitScope()
if ctx.RETURN():
if ctx.expr():
return_value = str(ctx.expr(0).getText())
self.body += '\tmovq $'+return_value+', %rax\n'
self.body += '\tret\n'
else:
self.body += '\tret\n'
if ctx.FOR():
self.st.enterScope()
start_value = ctx.expr(0)
end_value = ctx.expr(1)
self.body += '\tmovq $1, %rbx\n'
self.body += '\tjmp begin-for-'+str(self.LOOP_COUNT)+'\n'
self.body += 'begin-for-'+str(self.LOOP_COUNT)+':\n'
self.body += '\tcmp $'+str(end_value)+ ', %rbx\n'
self.body += '\tjge end-for-'+str(self.LOOP_COUNT)+'\n'
visit = self.visitChildren(ctx)
self.body += '\taddq $1, %rbx\n'
self.body += '\tjmp begin-for-'+str(self.LOOP_COUNT)+'\n'
self.body += 'end-for-'+str(self.LOOP_COUNT)+':\n'
self.body += '\tret\n'
self.LOOP_COUNT = self.LOOP_COUNT + 1
self.st.exitScope()
visit = self.visitChildren(ctx)
return visit
def visitStatement(self, ctx: DecafParser.StatementContext):
line_number = ctx.start.line
statmentName = ctx.location()
if ctx.expr():
#visit first expression
self.visit(ctx.expr(0))
#move the stack pointer and save value of first expression
self.st.stack_pointer[-1] += 8
self.body += 'movq %rax, ' + str(
-self.st.stack_pointer[-1]) + '(%rsp)\n'
#visit second expression
self.visit(ctx.expr(0))
self.body += 'movq ' + str(
-self.st.stack_pointer[-1]) + '(%rsp), %r10\n'
self.st.stack_pointer[-1] -= 8
self.body += 'movq %rax, %r11\n'
"""if a loction exists then assign the locaton varible to look on the symbol table"""
if ctx.location():
location = self.st.lookup(ctx.location().getText())
if ctx.expr():
expr = ctx.expr(0).expr(0)
if expr.literal():
if self.st.lookup(location.id).type == "boolean":
try:
"""if the lookup if type returns a boolean then try to int the expression if that is possible throw an error"""
int(ctx.expr(0).expr(0).getText())
print(
"ERROR: cannot assign boolean to int, line number:",
line_number)
except:
"""if that fails it can be assumed that the opertor is wrong"""
print(
"ERROR cannot use that operator with booleans, line number:",
line_number)
if ctx.breaknCon() != None:
self.breakncon = ctx.breaknCon().getText()
if ctx.FOR():
"""try and int the item in side of the for loop if that fails error"""
for items in ctx.expr():
try:
int(items.getText())
except:
if items.location() != None:
if self.st.lookup(
items.location().getText()).type != "int":
print("ERROR: type is not int. Line number:",
line_number)
else:
print(
"ERROR: type int must be used here in for loop. Line number:",
line_number)
"""
if an if statment exists then check
if the expression is an boolean
check if you are comparing two things of the same types
"""
if ctx.IF() != None:
if ctx.expr(0).bin_op() == None:
if self.st.lookup(ctx.expr(0).getText()).type != "boolean":
print(
"ERROR", "cannot evaluate type " +
self.st.lookup(ctx.expr(0).getText()).type +
" to boolean, on line:", line_number)
else:
"""get the eq operator """
self.eq_op = ctx.expr(0).bin_op().eq_op().getText()
if ctx.expr(0).bin_op():
"""get the bin op """
bin_op = ctx.expr(0).bin_op().getText()
ids = ctx.expr(0).getText().replace(bin_op, "")
"""make a list out of all the ids"""
listOfIds = list(ids)
"""compare the operands of of bin_op and if they are not the same type then error"""
if self.st.lookup(listOfIds[0]).type != self.st.lookup(
listOfIds[1]).type:
print(
"cannot compare " +
self.st.lookup(listOfIds[0]).type + " with " +
self.st.lookup(listOfIds[1]).type + " line number",
line_number)
else:
"""if bin op is not found get the type of the expression and if it's not boolean, throw an error"""
if self.st.lookup(ctx.expr(0).getText()).type != "boolean":
print(
"ERROR: " + "cannot evaluate type int line number",
line_number)
if self.eq_op != None:
expression = ctx.expr(0).getText()
ids = expression.replace(self.eq_op, "")
idList = list(ids)
"""check if the operands logical and or both boolean"""
if self.st.lookup(idList[0]).type and self.st.lookup(
idList[1]).type != "boolean":
print("ERROR: cannot use logical not here. Line number:",
line_number)
expr = ctx.expr(0)
expArrry = []
if expr != None:
if "+ " in expr.getText():
"""make an array of the epressions"""
expArrry = expr.replace("+", ",")
expArrry = expArrry.split(",")
var_name = None
varnames = None
for varnames in expArrry:
var_name = self.st.lookup(varnames)
if var_name != None:
pass
else:
"""error if symbol is on symbol table already"""
print(
"ERROR: varible referanced but never assinged " + " '" +
varnames + "' " + "on line", line_number)
if statmentName != None:
var_symbol = self.st.lookup(statmentName.getText())
if var_symbol != None:
pass
else:
print("ERROR:", "varible referanced but never assinged", "'",
statmentName.getText() + "'", "on line", line_number)
return self.visitChildren(ctx)