import failed: "package does not exist"

[misty hollow]

Hi. I have the following scripts in the same folder:

Statements.java

public class Statements {
    public static class Equal<T1,T2> {
        T1 a;
        T2 b;

        public Equal(T1 a, T2 b){
            this.a = a;
            this.b = b;
        }
    }
}

Axioms.java

import Statements.Equal;

public class Axioms {
    public static <T> Equal<T,T> EqRefl(T a) {
        return new Equal<T,T>(a,a);
    }

    public static <T1,T2> Equal<T1,T2> EqComm(Equal<T1,T2> eq) {
        return new Equal<T2,T1>(eq.b,eq.a);
    }

    public static <T1,T2,T3> Equal<T1,T3> EqTrans(Equal<T1,T2> eq1, Equal<T2,T3> eq2) {
        if (eq1.b != eq2.a) {
            throw new RuntimeException("second operand of first equality must be first operand of second equality");
        }
        return new Equal<T1,T3>(eq1.a,eq2.b);
    }
}

When I try to compile the latter with javac Axioms.java, I get the error Axioms.java:1: error: package Statements does not exist

[tired badge]

Detected code, here are some useful tools:

<@&987246399047479336> please have a look, thanks.

[undone egret]

When I try to compile the latter with javac Axioms.java, I get the error Axioms.java:1: error: package Statements does not exist
Don't compile manually, use an ide

And to answer your question, you need to give to java the list of all the files you want to compile

so javac Axioms.java Statements.java or simply javac *.java

import Statements.Equal;
Also, this needs to be import static Statements.Equal;

[misty hollow]

I am using VSC. If there is any way to automate compiling, I am not aware of it. I'm using the VSC console for that

[undone egret]

There is an extension pack that you should download
Or just use Intellij, it's the best IDE out there

[undone egret]

did you do that ?

[misty hollow]

yes

[undone egret]

ah

[misty hollow]

the latter, specifically (not that it matters)

[undone egret]

you probably need to put them in a package

[misty hollow]

I put package proofs; (proofs being the name of the folder they're in) at the top of both files

The error message does not seem to have changed

[undone egret]

import static proofs.Statements.Equal; ?

[misty hollow]

...oh! obviously...

YIKES okay good thing I finally installed the Java extension

[undone egret]

I still advise you to use Intellij instead of using vsc
Even with extensions, it's still crappy

Also

why do you create a class to put a class ?

[misty hollow]

It's going to have more classes in the future

[undone egret]

why do you not use a package instead ?

[misty hollow]

uh... oh

hm

[undone egret]

delete statements class

and use a package instead

[misty hollow]

I do like the fact Equal is of type Statement here though. I guess I should be putting them in separate files, shouldn't I?

[undone egret]

It's not ?
Equal isn't of type Statement

it's a class within Statements class

should be a package

Also you can use record Equal<T1, T2>(T1 a, T2 b) {} instead of what you have

@misty hollow

[misty hollow]

What's record?

[undone egret]

a new kind of class

an immutable class where you declare the fields in the class declaration itself

constructors, getters, equals, hashcode, toString are automatically generated

and you can pattern match on it

@misty hollow

[misty hollow]

Yeah sorry had to go for a bit

I managed to get everything to compile properly

As for everything else, I'll work on it later