Unable to convert strings to integers inside closure

[markjreed]

Tried to create a simple comparator to use with 🦁 to sort a list of numeric strings in reverse order:

🍇a🔡b🔡➡️ 🔢
↩️ 🔢b 10❗️➖ 🔢a 10❗️
🍉 ➡️ rev

But the compiler complains that " 🍬s🔢 does not provide methods.". Where did that 🍬 come from?

Assuming that meant they'd been wrapped into Optionals somehow, I tried to unwrap them with 🍺, but got "🍺 can only be used with optionals or error-prone calls."

Not sure what's going on here.

[Joe Skeen]

Hey @markjreed , I took a look at your code and the documentation and I think I know what is going on here.

According to the documentation, calling 🔢❗️returns a 🍬🔢, which means an optional of type number. You can read more about it in the guide on optionals, but essentially this protects the program against the possibility of an invalid value being passed into the function, for example the string 🔤sldkfjsldkj🔤 cannot be parsed as a 🔢. So after parsing you can compare the result to No Value (🤷) then if it's not that you can use the 🍺 operator to unwrap the optional (🍬) to a 🔢. Does that make sense?

The only other alternative would be to make the function error-prone and just use the 🍺 without checking, but I'm not sure you would want to go that route for this example.

Thanks for using Emojicode!

[Joe Skeen]

Here is a full working example:

🏁 🍇
    🍇a🔡b🔡➡️ 🔢
        🔢a 10❗ ➡️ aInt?
        🔢b 10❗ ➡️ bInt?
        ↪️ aInt? 🙌 🤷 🤝 bInt? 🙌 🤷 🍇
            💭 They are both invalid, treat them as the same
            ↩️ 0
        🍉 🙅↪️ aInt? 🙌 🤷 🍇
            💭 a is invalid, put b first
            ↩️ 1
        🍉 🙅↪️ bInt? 🙌 🤷 🍇
            💭 b is invalid, put a first
            ↩️ -1
        🍉 🙅 🍇
            ↩️ 🍺bInt? ➖ 🍺aInt?
        🍉
    🍉 ➡️ rev

    🍿
        🔤123🔤
        🔤321🔤
        🔤asdf🔤
    🍆 ➡️ 🖍️🆕list

    🦁list rev❗

    🔂 item list 🍇
        😀item❗
    🍉
🍉

The output is:

321
123
asdf

Personal style note: I like to use the ? character in my variable names when I know they are going to be optionals. That way I remember to unwrap them or handle them properly. Since Emojicode will allow pretty much any non-emoji character (excluding whitespace) in variable names, it works pretty well for me.

[Joe Skeen]

Another approach would be to use 🐭❗ and 🐰❗to no longer have to deal with conversion from string to int in the sorting function:

🏁 🍇
    🍿
        🔤123🔤
        🔤321🔤
        🔤asdf🔤
    🍆 ➡️ list

    🍇 a🔡 ➡️ 👌
        🔢a 10❗ ➡️ aInt?
        ↩️ ❎aInt? 🙌 🤷❗
    🍉 ➡️ filterOutInvalidIntStrings
    🐭list filterOutInvalidIntStrings❗ ➡️ onlyIntStrings

    🍇 a🔡 ➡️ 🔢
        🔢a 10❗ ➡️ aInt?
        ↩️ 🍺aInt?
    🍉 ➡️ convertToInt
    🐰onlyIntStrings convertToInt❗ ➡️ 🖍️🆕ints

    
    🍇a🔢b🔢➡️ 🔢
        ↩️ b ➖ a
    🍉 ➡️ rev
    🦁ints rev❗

    🔂 item ints 🍇
        😀🔤🧲item🧲🔤❗
    🍉
🍉

The output is:

321
123

[markjreed]

Oh, of course. It was complaining about 🍬🔢, not 🍬🔡, so it was the result of the 🔢 calls that needed unwrapping, not the parameters. D'oh! Thanks for the help!