def validate_text(text):
try:
BNF().parseString(text.replace('x', str(0)), parseAll=True)
fn.evaluate_stack(fn.exprStack)
print('validated')
except fn.ParseException as pe:
print(text, "failed parse:", str(pe))
return False
except Exception as e:
print(text, "failed eval:", str(e), fn.exprStack)
return False
return True
def calculate_y_values(x_values, expression): # Формирование значений оси у по функции
expression = expression.replace('X', 'x')
y_values = []
for x in x_values:
fn.exprStack = []
try:
BNF().parseString(expression.replace('x', str(x)), parseAll=True)
x_value = fn.evaluate_stack(fn.exprStack)
except fn.ParseException as pe:
print(expression, "failed parse:", str(pe))
return 0
except Exception as e:
print(expression, "failed eval:", str(e), fn.exprStack)
return 0
y_values.append(x_value)
return y_values
# op1 = evaluateStack( s )
# return opn[op]( op1, op2 )
# elif op == "PI":
# return math.pi # 3.1415926535
# elif op == "E":
# return math.e # 2.718281828
# elif op in fn:
# return fn[op]( evaluateStack( s ) )
# elif op[0].isalpha():
# if op in variables:
# return variables[op]
# raise Exception("invalid identifier '%s'" % op)
# else:
# return float( op )
arithExpr = BNF()
ident = Word(alphas, alphanums).setName("identifier")
assignment = ident("varname") + '=' + arithExpr
pattern = assignment | arithExpr
if __name__ == '__main__':
# input_string
input_string = ''
# Display instructions on how to quit the program
print("Type in the string to be parsed or 'quit' to exit the program")
input_string = input("> ")
while input_string.strip().lower() != 'quit':
if input_string.strip().lower() == 'debug':
debug_flag = True