def handle_token(token, input_stream):
token_is_literal, parsed = is_a_literal(token)
if token_is_literal:
# Push literals on to the Data stack
Data.push(parsed)
elif token in Words.keys():
# token is a Word -- call it!
call_word(token)
elif token in Memory.keys():
# Get a variable definition or redefine existing variable
set_or_get_variable(token, input_stream)
elif token == "see":
# Show a Word's definition
show_definition(next(input_stream))
elif token == ":":
# Define a new Word
define_word(input_stream)
elif token == "?DO":
# Execute DO loop
doloop_body = take_tokens("?DO", "LOOP", input_stream)
run_doloop(doloop_body)
elif token == "BEGIN":
# Execute WHILE loop
whileloop_body = take_tokens("BEGIN", "WHILE", input_stream)
run_whileloop(whileloop_body)
elif token == "IF":
# Handle Conditionals
run_conditional(input_stream)
elif token == "variable":
# Declare the existence of a new variable in Memory
declare_variable(next(input_stream))
else:
raise SyntaxError(f"""I don't know what to do with `{token}` !!!""")
def set_or_get_variable(token, input_stream):
next_token = next(input_stream)
if next_token not in ("!", "@"):
input_stream.clear()
raise SyntaxError(
f"""Was trying to get or set '{token}', but missing ! or @""")
if next_token == "!":
Memory[token] = Data.pop()
else: # next_token == "@"
Data.push(Memory[token])