makeVisualTree function
This function logs a visual tree of the formula to the console.
Implementation
void makeVisualTree(String formula) {
String spaces = ' ';
print('\n');
print('\n');
print(formula);
print('$spaces|');
print('$spaces|');
for (int i = 0; i < patternParser(formula).length; i++) {
String tokenType = patternParser(formula)[i][0];
String token = patternParser(formula)[i][1];
print('$spaces|');
print('$spaces--- $tokenType: $token');
}
print('\n');
print('\n');
}