module pind.samples.ja.value_vs_reference.value_vs_reference_4;

import std.stdio;
import std.array;

int moduleVariable = 9;

class MyClass {
    int member;
}

void printHeader() {
    immutable dchar[] header =
        "                     Type of variable" ~
        "                      a == b  &a == &b";

    writeln();
    writeln(header);
    writeln(replicate("=", header.length));
}

void printInfo(const dchar[] label,
               bool valueEquality,
               bool addressEquality) {
    writefln("%55s%9s%9s",
             label, valueEquality, addressEquality);
}

void main() {
    printHeader();

    int number1 = 12;
    int number2 = 12;
    printInfo("variables with equal values (value type)",
              number1 == number2,
              &number1 == &number2);

    int number3 = 3;
    printInfo("variables with different values (value type)",
              number1 == number3,
              &number1 == &number3);

    int[] slice = [ 4 ];
    foreach (i, ref element; slice) {
        printInfo("foreach with 'ref' variable",
                  element == slice[i],
                  &element == &slice[i]);
    }

    foreach (i, element; slice) {
        printInfo("foreach without 'ref' variable",
                  element == slice[i],
                  &element == &slice[i]);
    }

    outParameter(moduleVariable);
    refParameter(moduleVariable);
    inParameter(moduleVariable);

    int[] longSlice = [ 5, 6, 7 ];
    int[] slice1 = longSlice;
    int[] slice2 = slice1;
    printInfo("slices providing access to same elements",
              slice1 == slice2,
              &slice1 == &slice2);

    int[] slice3 = slice1[0 .. $ - 1];
    printInfo("slices providing access to different elements",
              slice1 == slice3,
              &slice1 == &slice3);

    auto variable1 = new MyClass;
    auto variable2 = variable1;
    printInfo(
        "MyClass variables to same object (reference type)",
        variable1 == variable2,
        &variable1 == &variable2);

    auto variable3 = new MyClass;
    printInfo(
        "MyClass variables to different objects (reference type)",
        variable1 == variable3,
        &variable1 == &variable3);
}

void outParameter(out int parameter) {
    printInfo("function with 'out' parameter",
              parameter == moduleVariable,
              &parameter == &moduleVariable);
}

void refParameter(ref int parameter) {
    printInfo("function with 'ref' parameter",
              parameter == moduleVariable,
              &parameter == &moduleVariable);
}

void inParameter(in int parameter) {
    printInfo("function with 'in' parameter",
              parameter == moduleVariable,
              &parameter == &moduleVariable);
}