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starlet.py
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starlet.py
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#!/usr/bin/env python3
import sys
new_exit_list = None # Used for loop/exit function
nextLabel = 0 # Label counter
quadDict = {} # A dict with key: Line number, and value: a quad(list)
tCounter = 1 # Token counter
lineno = 1 # Current line number of input file.
token_captivated = ['program', 'endprogram', 'declare', 'if', 'then', 'else',
'endif', 'while', 'endwhile', 'dowhile', 'enddowhile', 'loop', 'endloop', 'exit',
'forcase', 'endforcase', 'incase', 'endincase', 'when', 'default', 'enddefault',
'function', 'endfunction', 'return', 'in', 'inout', 'inandout', 'and', 'or', 'not',
'input', 'print']
scopes_list = list() # A list of scopes
loop_enabled = False
func_enabled = False
ret_enabled = False
asm_file = None
parlist = list()
lmain_flag = True
#########################################################
# LEX #
#########################################################
# State: 1-> words 3-> '<' 5-> ':'
# 2-> digits 4-> '>' 6-> '/'
def lex():
buffer = []
state = 0 # Initial FSM state (starting point)
ok = -2 # Final State
getback = False # True if we need to reposition file pointer
# Lexical analyzer's FSM implementation
while state != ok:
char = data.read(1) # Reading one character at a time
buffer.append(char)
if state == 0:
if char.isalpha():
state = 1
elif char.isdigit():
state = 2
elif char == '<':
state = 3
elif char == '>':
state = 4
elif char == ':':
state = 5
elif char == '/':
state = 6
elif char in ('+', '-', '*', '=', ',', ';', '(', ')', '[', ']'):
state = ok
elif char == '':
state = ok
elif char.isspace():
state = 0
else:
print("(lex) invalid character: " + char)
sys.exit()
elif state == 1:
if not char.isalnum():
getback = True
state = ok
elif state == 2:
if not char.isdigit():
if char.isalpha():
error(" (lex) not valid integer: ")
getback = True
state = ok
elif state == 3:
if char != '=' and char != '>':
getback = True
state = ok
elif state == 4:
if char != '=':
getback = True
state = ok
elif state == 5:
if char != '=':
getback = True
state = ok
elif state == 6:
if char == '/':
state = 7
elif char == '*':
state = 8
else:
getback = True
state = ok
elif state == 7:
if char == '\n':
del buffer[:]
state = 0
elif state == 8:
if char == '*':
state = 9
elif char == '':
print("No closing comment found")
sys.exit()
elif state == 9:
if char == '/':
del buffer[:]
state = 0
else:
state = 8
# Ignoring spaces and counting lines
if char.isspace():
if char == '\n':
global lineno
lineno += 1
if len(buffer) != 0:
del buffer[-1]
getback = False
# Repositioning file pointer
if getback:
data.seek(data.tell() - 1)
del buffer[-1]
ret = ''.join(buffer)
# Checking if digit is out of bounds
if ret.isdigit():
if abs(int(ret)) > 32767:
error("(lex) digit is out of bounds! ")
# Emptying the buffer
del buffer[:]
# Returning the first 30 characters
return ret[:30]
##################################################################
# SYNTAX #
##################################################################
def program():
global token, program_name, scopes_list
token = lex()
if token == 'program':
token = lex()
if is_valid_id(token):
program_name = name = token
token = lex()
# Creating and adding Scope to scopes_list(default nesting_level = 0)
scopes_list.append(Scope())
block(name)
if token != 'endprogram':
error("expected endprogram, found: ")
else:
error(" (program) expected an 'id' found: ")
else:
error("(program) expected 'program' found: ")
def block(name):
declarations()
subprograms()
# Setting start_quad(LineNo of .int where the current function starts) for each Function(Entity)
start_quad = next_quad()
if name != program_name:
en = search_entity(name, 'FUNC')[0]
en.set_start_quad(start_quad)
gen_quad('begin_block', name)
statements()
if program_name == name:
gen_quad('halt')
else:
# Update framelength
f_entity = search_entity(name, 'FUNC')[0]
f_entity.framelength = scopes_list[len(scopes_list) - 1].get_sp()
gen_quad('end_block', name)
# Printing Scopes and entities before deleting it
print(scopes_list[-1])
for en in scopes_list[-1].entities:
print(en)
print("--------------------------------------------")
for i in range(start_quad, nextLabel):
write_to_asm(quadDict[i], name, i)
# Block is done, deleting Scope
del scopes_list[-1]
def declarations():
global token
while token == 'declare':
token = lex()
varlist()
if token != ';':
error(" (declarations) expected ';' found: ")
token = lex()
def varlist():
global token
if is_valid_id(token):
# Adding (declarations)token as a Variable entity
add_var_entity(token)
token = lex()
while token == ',':
token = lex()
if not is_valid_id(token):
error(" (varlist) expected 'id', found: ")
# Adding token as a Variable entity
add_var_entity(token)
token = lex()
elif token != ';':
error(" (varlist) not valid id: ")
# Storing the declarations of the current scope to the previous (Enclosing scope)
# if len(scopes_list) >= 2:
# scopes_list[-2].set_enclosing_scope(scopes_list[-1].entities)
def subprograms():
global token, func_enabled
while token == 'function':
func_enabled = True
token = lex()
subprogram()
def subprogram():
global token, func_enabled, ret_enabled
if is_valid_id(token):
name = token
# Creating and adding new scope (nesting level depends on the length of our scopes_list)
new_scope = Scope(scopes_list.__len__(), scopes_list[-1])
scopes_list.append(new_scope)
token = lex()
# Adding Func entity
scopes_list[-2].add_entity(Function(name, 0))
funcbody(name)
if token != 'endfunction':
error(" (subprogram) expected endfuction, found: ")
if not ret_enabled:
error(" No return in function/")
func_enabled = False
ret_enabled = False
token = lex()
else:
error("(subprogram) expected 'id', found: ")
def funcbody(name):
formalpars(name)
block(name)
def formalpars(name):
global token
if token == '(':
token = lex()
formalparlist(name)
if token != ')':
error(" (formalpars) expected ')', found: ")
else:
error(" (formalpars) expected '(', found: ")
token = lex()
def formalparlist(name):
global token
if token != ')':
formalparitem(name)
while token == ',':
token = lex()
formalparitem(name)
def formalparitem(name):
global token
if token in ('in', 'inout', 'inandout'):
par_mode = token
token = lex()
if is_valid_id(token):
# Add Argument(in/inout/inandout) to func
add_arg_to_func(par_mode, name)
# Add Parameter(Entity) to Scope
add_param_entity(token, par_mode)
token = lex()
else:
error("(formalparitem) expected id, found: ")
else:
error("expected 'in'/'inout'/'inandout', found: ")
def statements():
global token
statement()
while token == ';':
token = lex()
statement()
def statement():
global token, loop_enabled, ret_enabled
if token == 'if':
token = lex()
if_stat()
elif token == 'while':
token = lex()
while_stat()
elif token == 'dowhile':
token = lex()
do_while_stat()
elif token == 'loop':
loop_enabled = True
token = lex()
loop_stat()
elif token == 'exit':
token = lex()
if loop_enabled:
exit_stat()
else:
error(" 'exit' must be declared inside a loop ")
elif token == 'forcase':
token = lex()
forcase_stat()
elif token == 'incase':
token = lex()
incase_stat()
elif token == 'return':
ret_enabled = True
token = lex()
exp = expression()
gen_quad('retv', exp, '_', '_')
elif token == 'print':
token = lex()
exp = expression()
gen_quad('out', exp)
elif token == 'input':
token = lex()
id_place = input_stat()
gen_quad('inp', id_place)
elif is_valid_id(token):
assignment_stat()
def assignment_stat():
global token
if token.isalnum():
t1 = token
if not exists(t1):
error(' Not declared: ')
token = lex()
if token == ':=':
op = token
token = lex()
if not exists(token) and not token.isdigit():
error(' Not declared: ')
exp = expression()
gen_quad(op, exp, '_', t1)
else:
error("(assignment_stat) expected ':=' found ")
def if_stat():
global token
if token == '(':
token = lex()
else:
error("(if_stat) expected '(' found: ")
(b_true, b_false) = condition()
if token == ')':
token = lex()
backpatch(b_true, next_quad())
else:
error("(if_stat) expected ')' found: ")
if token == 'then':
token = lex()
statements()
skip = make_list(next_quad())
gen_quad('jump')
backpatch(b_false, next_quad())
elsepart()
backpatch(skip, next_quad())
if token != 'endif':
error("(if_stat) expected 'endif' found ")
token = lex()
else:
error("(if_stat) expected 'then' found ")
def elsepart():
global token
if token == 'else':
token = lex()
statements()
def while_stat():
global token
quad = next_quad()
if token == '(':
token = lex()
else:
error("(while_stat) expected '(' found: ")
(b_true, b_false) = condition()
if token == ')':
token = lex()
else:
error("(while_stat) expected ')' found: ")
backpatch(b_true, next_quad())
statements()
gen_quad('jump', '_', '_', str(quad))
backpatch(b_false, next_quad())
if token != 'endwhile':
error(" (while_stat) expected 'endwhile', found: ")
token = lex()
def do_while_stat():
global token
quad = next_quad()
statements()
if token == 'enddowhile':
token = lex()
if token == '(':
token = lex()
else:
error("(do_while_stat) expected '(' found: ")
(b_true, b_false) = condition()
if token == ')':
backpatch(b_true, quad)
n_quad = next_quad()
backpatch(b_false, n_quad)
token = lex()
else:
error("(do_while_stat) expected ')' found: ")
else:
error(" (do_while_stat) expected 'enddowhile', found: ")
def loop_stat():
global token, new_exit_list, loop_enabled
quad = next_quad()
statements()
gen_quad('jump', '_', '_', str(quad))
if token != 'endloop':
error(" (loop_stat) expected 'endloop', found: ")
loop_enabled = False
token = lex()
if new_exit_list is not None:
backpatch(new_exit_list, next_quad())
new_exit_list = None
def exit_stat():
global token, new_exit_list
new_exit_list = make_list(next_quad())
gen_quad('jump')
def forcase_stat():
global token
flag_quad = next_quad()
exit_list = empty_list()
while token == 'when':
token = lex()
if token == '(':
token = lex()
else:
error("(forcase_stat) expected '(' found: ")
(b_true, b_false) = condition()
backpatch(b_true, next_quad())
if token == ')':
token = lex()
else:
error("(forcase_stat) expected ')' found: ")
if token != ':':
error("(forcase_stat) expected ':', found: ")
token = lex()
statements()
t = make_list(next_quad())
gen_quad('jump')
exit_list = merge(exit_list, t)
backpatch(b_false, next_quad())
if token != 'default':
error("(forcase_stat) expecred 'default',found: ")
token = lex()
if token != ':':
error("(forcase_stat) expected ':', found: ")
token = lex()
statements()
gen_quad('jump', '_', '_', str(flag_quad))
backpatch(exit_list, next_quad())
if token != 'enddefault':
error("(forcase_stat) expected 'enddefault',found: ")
token = lex()
if token != 'endforcase':
error("(forcase_stat) expected 'endforcase',found: ")
token = lex()
def incase_stat():
global token
t = new_temp()
flag_quad = next_quad()
gen_quad(':=', '0', '_', t)
while token == 'when':
token = lex()
if token == '(':
token = lex()
else:
error("(incase_stat) expected '(' found: ")
(b_true, b_false) = condition()
backpatch(b_true, next_quad())
gen_quad(':=', '1', '_', t)
if token == ')':
token = lex()
else:
error("(incase_stat) expected ')' found: ")
if token != ':':
error("(incase_stat) expected ':', found: ")
token = lex()
statements()
backpatch(b_false, next_quad())
if token != 'endincase':
error("(incase_stat) expected 'endincase',found: ")
token = lex()
gen_quad('=', '1', t, str(flag_quad))
def input_stat():
global token
if not is_valid_id(token):
error(" (input_stat) expected an 'id', found: ")
ret = token
token = lex()
return ret
def actualpars():
global token
if token == '(':
token = lex()
actualparlist()
if token != ')':
error(" (actualpars) expected ')', found: ")
token = lex()
return True
def actualparlist():
global token
actualparitem()
while token == ',':
token = lex()
actualparitem()
def actualparitem():
global token
if token == 'in':
token = lex()
if not exists(token):
error(' Not declared: ')
exp = expression()
gen_quad('par', exp, 'CV')
elif token == 'inout':
token = lex()
if not exists(token):
error(' Not declared: ')
t1 = token
if not is_valid_id(token):
error("(actualparitem) expected 'id' found ")
token = lex()
gen_quad('par', t1, 'REF')
elif token == 'inandout':
token = lex()
if not exists(token):
error(' Not declared: ')
t2 = token
if not is_valid_id(token):
error("(actualparitem) expected 'id' found ")
token = lex()
gen_quad('par', t2, 'RET')
def condition():
global token
(b_true, b_false) = boolterm()
while token == 'or':
backpatch(b_false, next_quad())
token = lex()
(c_true, c_false) = boolterm()
b_true = merge(b_true, c_true)
b_false = c_false
return b_true, b_false
def boolterm():
global token
(b_true, b_false) = boolfactor()
while token == 'and':
backpatch(b_true, next_quad())
token = lex()
(c_true, c_false) = boolfactor()
b_false = merge(b_false, c_false)
b_true = c_true
return b_true, b_false
def boolfactor():
global token
if token == 'not':
token = lex()
if token == '[':
token = lex()
ret = condition()
if token != ']':
error(" (boolfactor) expected ']', found: ")
token = lex()
else:
error(" (boolfactor) expected '[', found: ")
elif token == '[':
token = lex()
ret = condition()
if token != ']':
error(" (boolfactor) expected ']', found: ")
token = lex()
else:
exp1 = expression()
op = relational_oper()
exp2 = expression()
b_true = make_list(next_quad())
gen_quad(op, exp1, exp2)
b_false = make_list(next_quad())
gen_quad('jump')
ret = (b_true, b_false)
return ret
def expression():
global token
op = optional_sign()
t1 = term()
while add_oper():
op = token
token = lex()
if not exists(token) and not token.isdigit():
error(' Not declared: ')
t2 = term()
tmp = new_temp()
gen_quad(op, t1, t2, tmp)
t1 = tmp
return t1
def term():
global token
f1 = factor()
while mul_oper():
op = token
token = lex()
f2 = factor()
tmp = new_temp()
gen_quad(op, f1, f2, tmp)
f1 = tmp
return f1
def factor():
global token
if token.isdigit():
ret = token
token = lex()
elif token == '(':
token = lex()
ret = expression()
if token != ')':
error("(factor) expected ')' found ")
token = lex()
elif is_valid_id(token):
ret = token
token = lex()
tail = idtail()
if tail is not None:
new = new_temp()
gen_quad('par', new, 'RET')
gen_quad('call', ret)
ret = new
else:
error("(factor) expected something found ")
return ret
def idtail():
global token
if token == '(':
return actualpars()
def optional_sign():
global token
if add_oper():
token = lex()
return token
def relational_oper():
global token
if token not in ('=', '<=', '>=', '>', '<', '<>'):
error(" (relational_oper) expected a relation sign ")
ret = token
token = lex()
return ret
def add_oper():
global token
if token == '+' or token == '-':
# token = lex() tin vgalame kai tin kaloume meta tin add_oper()
return True
return False
def mul_oper():
global token
if token == '*' or token == '/':
# token = lex() gia ton idio logo me ad_oper()
return True
return False
#################################################################
# #
# INT #
# #
#################################################################
def next_quad():
return nextLabel
def gen_quad(op=None, x='_', y='_', z='_'):
global nextLabel
currentlabel = nextLabel
nextLabel += 1
quad = [op, x, y, z]
quadDict[currentlabel] = quad
def new_temp():
global tCounter
temp = "T_" + str(tCounter)
tCounter += 1
# Create/Add new TempVariable to the current list of entities
scopes_list[-1].add_entity(TempVariable(temp, scopes_list[-1].get_sp()))
return temp
def empty_list():
return list()
def make_list(x):
newlist = list()
newlist.append(x)
return newlist
def merge(list1, list2):
return list1 + list2
def backpatch(labellist, z):
global quadDict
for key in labellist:
if key in quadDict:
quadDict[key].pop()
quadDict[key].append(z)
##################################################################
# #
# SYMBOL TABLE #
# #
##################################################################
class Entity:
def __init__(self, name, entity_type):
self.name = name
self.entity_type = entity_type
self.next = None
def __str__(self):
return self.name + ': ' + self.entity_type
# Variable inherits from Entity
class Variable(Entity):
def __init__(self, name, offset=0):
# Calling 'fathers' constructor and setting offset
Entity.__init__(self, name, 'VAR')
self.offset = offset
def __str__(self):
return Entity.__str__(self) + '\toffset: ' + str(self.offset)
# Function inherits from Entity
class Function(Entity):
def __init__(self, name, ret_val, start_quad=-1):
Entity.__init__(self, name, 'FUNC')
self.ret_val = ret_val
self.start_quad = start_quad
self.arguments = list()
self.framelength = -1
def set_framelength(self, x):
self.framelength = x
def set_start_quad(self, x):
self.start_quad = x
def set_ret_val(self, x):
self.ret_val = x
def __str__(self):
return Entity.__str__(self) + \
',\tStart_quad: ' + self.start_quad.__str__() + \
',\tFramelength:' + str(self.framelength) + \
',\tArgs:' + self.arguments.__str__()
# Parameter inherits from Entity
class Parameter(Entity):
def __init__(self, name, par_mode, offset=0):
Entity.__init__(self, name, 'PAR')
if par_mode == 'in':
self.par_mode = 'cv'
elif par_mode == 'inout':
self.par_mode = 'ref'
else:
self.par_mode = 'ret'
self.offset = offset
def __str__(self):
return Entity.__str__(self) + ',\tpar_mode: ' + self.par_mode + ',\toffset: ' + str(self.offset)
# TempVariable inherits from Entity
class TempVariable(Entity):
def __init__(self, name, offset=0):
Entity.__init__(self, name, 'TMPVAR')
self.offset = offset
def __str__(self):
return Entity.__str__(self) + '\toffset: ' + str(self.offset)
class Scope:
def __init__(self, nesting_level=0, enclosing_scope=None):
self.entities = list()
self.nesting_level = nesting_level
self.enclosing_scope = enclosing_scope
self.sp = 12
def get_sp(self):
ret = self.sp
self.sp += 4
return ret
# Adding entity to list
def add_entity(self, ent):