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
'Parse Failure', input_string,
(str(err), err.line, err.column)
]
# show result of parsing the input string
if debug_flag: print(input_string, "->", L)
if len(L) == 0 or L[0] != 'Parse Failure':
if debug_flag: print("exprStack=", exprStack)
for i, ob in enumerate(exprStack):
if isinstance(ob, str) and ob in variables:
exprStack[i] = str(variables[ob])
# calculate result , store a copy in ans , display the result to user
try:
result = evaluate_stack(exprStack)
except Exception as e:
print(str(e))
else:
variables['ans'] = result
print(result)
# Assign result to a variable if required
if L.varname:
variables[L.varname] = result
if debug_flag: print("variables=", variables)
else:
print('Parse Failure')
err_str, err_line, err_col = L[-1]
print(err_line)
print(" " * (err_col - 1) + "^")