How about add the ability to calculate simple formulas in Notepad2-mod?

[bluenlive]

Hello.

Often, while writing in Notepad2-mod, I need to do a simple calculation, and I use a calculator app to do it.
I realized that it would be nice to be able to do simple calculations in Notepad2-mod.

What do you think?

[PNBRQK]

That's exactly what Notepad2e claims to do

[zufuliu]

They use https://github.com/codeplea/tinyexpr

[bluenlive]

Thanks. ;)

[bluenlive]

I added this feature to the version I distribute.
I implemented it to calculate the expression when Ctrl+Enter is pressed.
However, I modified the ScintillaWin.cxx file to implement that functionality in the WM_KEYDOWN to VK_ENTER handling, and I'm not sure if that's the right approach.
Is there a more appropriate approach?

[zufuliu]

what about using accelerators for Tools -> Evaluate Expression menu:

    VK_RETURN,      IDM_EDIT_EVAL,              VIRTKEY, CONTROL, NOINVERT
    VK_RETURN,      CMD_CTRLENTER,              VIRTKEY, SHIFT, CONTROL, NOINVERT

As I use Python as my calculator, this feature will be delayed.

[bluenlive]

what about using accelerators for Tools -> Evaluate Expression menu:

    VK_RETURN,      IDM_EDIT_EVAL,              VIRTKEY, CONTROL, NOINVERT
    VK_RETURN,      CMD_CTRLENTER,              VIRTKEY, SHIFT, CONTROL, NOINVERT

As I use Python as my calculator, this feature will be delayed.

Thanks! I'll try it!

[zufuliu]

I think to implement this, we need another library or modify tinyexpr (exe will be 60 KiB larger) to dynamic load math functions from ucrtbase.dll or msvcrt.dll (there are about 100 math functions after excluding long double and float overloads), similar to e5dd9a4 (which makes Notepad2 12 KiB smaller).

Another solution is load Python DLL (assume most user have Python installed), and use PyRun_String() to evaluate expression.

[Matteo-Nigro]

Hi @zufuliu I think this functionality is something that Notepad must have.
I too often have to switch from the editor to the calculator all the time for certain tasks. As far as the library is concerned, I would suggest using dlls that are not linked to other installations. Although we all have python 😀, it would be sad not to use the functionality if it were not available. Notepad is standalone and should work no matter what system it is running on.

[Matteo-Nigro]

Is there any news on this implementation? In which release could it be included? 😉

[zufuliu]

Is there any news on this implementation? In which release could it be included?

No action yet, probably post v4.24.01.

[zufuliu]

It would better to known what functionalities the expression evaluator needs to support.

Following is a simple (currently only supports +, -, *, /, %, ^, ( and )) interactive calculator, is this enough for general use?

// cl /EHsc /std:c++20 /W4 /DNDEBUG /MD /Ox /Ot /FAcs /GS- /GR- calc.cpp
#include <cmath>
#include <cstring>
#include <string>
#include <iostream>

enum class Precedence {
    None,
    Primary,
    Addition,
    Multiplication,
    Power,
};

constexpr Precedence GetPrecedence(int op) noexcept {
    switch (op) {
    case '+':
    case '-':
        return Precedence::Addition;
    case '*':
    case '/':
    case '%':
        return Precedence::Multiplication;
    case '^':
        return Precedence::Power;
    default:
        return Precedence::None;
    }
}

double Evaluate(const char *input, char **end, Precedence parent = Precedence::None) {
    double result = 0;
    while (*input) {
        const unsigned char ch = *input;
        switch (ch) {
        case '0':
        case '1':
        case '2':
        case '3':
        case '4':
        case '5':
        case '6':
        case '7':
        case '8':
        case '9':
        case '.': {
            const double value = strtod(input, end);
            if (*end == input) {
                return result;
            }
            input = *end;
            result = value;
        } break;

        case '+':
        case '-':
        case '*':
        case '/':
        case '%':
        case '^': {
            const Precedence precedence = GetPrecedence(ch);
            if (precedence < parent) {
                *end = const_cast<char *>(input);
                return result;
            }
            ++input;
            const double value = Evaluate(input, end, precedence);
            if (*end == input) {
                return result;
            }
            input = *end;
            switch (ch) {
            case '+':
                result += value;
                break;
            case '-':
                result -= value;
                break;
            case '*':
                result *= value;
                break;
            case '/':
                result /= value;
                break;
            case '%':
                result = fmod(result, value);
                break;
            case '^':
                result = pow(result, value);
                break;
            }
        } break;

        case '(': {
            ++input;
            const double value = Evaluate(input, end, Precedence::Primary);
            if (*end == input) {
                return result;
            }
            input = *end;
            result = value;
        } break;

        default:
            if (ch > ' ') {
                if (ch == ')' && parent == Precedence::Primary) {
                    ++input;
                }
                *end = const_cast<char *>(input);
                return result;
            }
            ++input;
            break;
        }
    }
    *end = const_cast<char *>(input);
    return result;
}

int main() {
    std::cout << ">>> ";
    std::string input;
    while (std::getline(std::cin, input, '\n')) {
        if (input.starts_with("exit") || input.starts_with("quit")) {
            break;
        }
        char *end = nullptr;
        const double result = Evaluate(input.c_str(), &end);
        std::cout << std::defaultfloat << result << '\n';
        if (*end) {
            std::cout << "unexpected end of input: " << end << '\n';
        }
        std::cout << ">>> ";
    }
    return 0;
}

[Matteo-Nigro]

Well, I'd say that it would be enough for 90% of the tasks, at least for mine... 😂 If you then wanted to add other features such as trigonometric calculations or other, you would always do it in time... 😉

[zufuliu]

I just pushed https://github.com/zufuliu/tinymath
fell free to download the code and play with the 500 lines calculator.