def forcaseStat():
global token
flag = intermediate.newTemp()
forQuad = intermediate.nextQuad()
intermediate.genQuad(":=", "0", "_", flag)
while token[0] != "endforcase":
if token[0] == "when":
token = lexi.lex()
(bTrue, bFalse) = condition()
intermediate.backPatch(bTrue, intermediate.nextQuad())
if token[0] == "upDownTk":
token = lexi.lex()
statements()
genQuad(":=", "1", "_", flag)
intermediate.backPatch(bFalse, intermediate.nextQuad())
else:
line = lexi.getLineAndColumn()
print("Syntax error: expected ':' at line " + str(line[0]+1)+".")
exit()
else:
line = lexi.getLineAndColumn()
print("Syntax error: expected 'when' at line " + str(line[0]+1)+".")
exit()
intermediate.genQuad("=", flag, "1", forQuad)
token = lexi.lex()
return
def whileStat():
global token
q = intermediate.nextQuad()
(bTrue, bFalse) = condition()
intermediate.backPatch(bTrue, intermediate.nextQuad())
statements()
intermediate.genQuad("jump","_","_", q)
intermediate.backPatch(bFalse,nextQuad())
if token[0] == "endwhile":
token = lexi.lex()
return
else:
print("Syntax error: 'endwhile' statement is missing. " )
exit()
def boolfactor():
global token
if token[0] == "not":
token = lexi.lex()
if token[0] == "leftlogicparenthesisTk":
token = lexi.lex()
(q1True, q1False) = condition()
if token[0] != "rightlogicparenthesisTk":
line = lexi.getLineAndColumn()
print("Syntax error: ']' statement is missing at line " + str(line[0]+1)+".")
exit()
token = lexi.lex()
return (q1False,q1True)
else:
line = lexi.getLineAndColumn()
print("Syntax error: '[' statement is missing at line " + str(line[0]+1)+".")
exit()
elif token[0] == "leftlogicparenthesisTk":
token = lexi.lex()
(q1True, q1False) = condition()
if token[0] != "rightlogicparenthesisTk":
line = lexi.getLineAndColumn()
print("Syntax error: ']' statement is missing at line " + str(line[0]+1)+".")
exit()
token = lexi.lex()
return (q1True, q1False)
elif token[0] == "true" or token[0] == "false":
if token[0] =="true":
q2True = intermediate.makeList(intermediate.nextQuad())
q2False = intermediate.emptyList()
intermediate.genQuad("true", "_", "_", "_")
else:
q2False = intermediate.makeList(intermediate.nextQuad())
q2True = intermediate.emptyList()
intermediate.genQuad("false", "_", "_", "_")
token = lexi.lex()
return (q2True, q2False)
else:
expression1 = expression()
relop = relationalOper()
expression2 = expression()
rTrue = makeList(intermediate.nextQuad())
intermediate.genQuad(relop, expression1, expression2, "_")
rFalse = makeList(intermediate.nextQuad())
intermediate.genQuad("jump", "_", "_", "_")
return (rTrue, rFalse)
def repeatStat():
global token
global exitList
global inRepeat
currentExitList = exitList #temp list with all the values
exitList = intermediate.emptyList() #clear the global exitList
inRepeat = True
bRepeat = intermediate.nextQuad() #beginning of repeat
while token[0] != "endrepeat":
statements()
inRepeat = False
genQuad("jump", "_", "_", bRepeat) #jump to the start of repeat
outOfRepeat = intermediate.nextQuad() #out of the repeat
backPatch(exitList, outOfRepeat) #backPatch the current out of repeat
exitList = currentExitList #give back to global list
token = lexi.lex()
return
def condition(): global token (q1True, q1False) = boolterm() bTrue = q1True bFalse = q1False while token[0] == "or": token = lexi.lex() intermediate.backPatch(bFalse, intermediate.nextQuad()) (q2True, q2False) = boolterm() bTrue = intermediate.merge(bTrue, q2True) bFalse = q2False return (bTrue, bFalse)
def switchStat():
global token
exitList = intermediate.emptyList()
e1 = expression()
while token[0] != "endswitch":
if token[0] == "case":
token = lexi.lex()
e2 = expression()
if token[0] == "upDownTk":
bTrue = intermediate.makeList(intermediate.nextQuad()) #references ["=", e1, e2, "_"]
intermediate.genQuad("=", e1, e2, "_")
bFalse = intermediate.makeList(intermediate.nextQuad()) #references ["jump", "_", "_", "_"]
intermediate.genQuad("jump", "_", "_", "_")
intermediate.backPatch(bTrue, intermediate.nextQuad()) # ["=", e1, e2, tells where to go]
token = lexi.lex()
statements()
tList = intermediate.makeList(intermediate.nextQuad())
intermediate.genQuad("jump", "_", "_", "_")
exitList = intermediate.merge(exitList, tList)
intermediate.backPatch(bFalse, intermediate.nextQuad())
else:
line = getLineAndColumn()
print("Syntax error: expected ':' at line " + str(line[0]+1)+".")
exit()
else:
line = lexi.getLineAndColumn()
print("Syntax error: 'endswitch' or 'case' statement is missing .")
exit()
intermediate.backPatch(exitList, intermediate.nextQuad())
token = lexi.lex()
return
def ifStat():
global token
(bTrue, bFalse) = condition()
if token[0] == "then":
intermediate.backPatch(bTrue, intermediate.nextQuad())
token = lexi.lex()
statements()
ifList = intermediate.makeList(intermediate.nextQuad())
intermediate.genQuad("jump","_","_","_")
intermediate.backPatch(bFalse, intermediate.nextQuad())
elsepart()
intermediate.backPatch(ifList, intermediate.nextQuad())
if token[0] == "endif":
token = lexi.lex()
return
else:
print("Syntax error: 'endif' statement is missing.")
exit()
else:
line = lexi.getLineAndColumn()
print("Syntax error: 'then' statement is missing at line " + str(line[0]+1)+".")
exit()