Module quantities.runtime

Example

import quantities.runtime;
import quantities.si;
import std.format : format;
import std.math : approxEqual;

// Note: the types of the predefined SI units (gram, mole, liter...)
// are Quantity instances, not QVariant instance.

// Introductory example
{
    // I have to make a new solution at the concentration of 5 mmol/L
    QVariant!double concentration = 5.0 * milli(mole) / liter;

    // The final volume is 100 ml.
    QVariant!double volume = 100.0 * milli(liter);

    // The molar mass of my compound is 118.9 g/mol
    QVariant!double molarMass = 118.9 * gram / mole;

    // What mass should I weigh?
    QVariant!double mass = concentration * volume * molarMass;
    assert(format("%s", mass) == "5.945e-05 [M]");
    // Wait! That's not really useful!
    assert(siFormat!"%.1f mg"(mass) == "59.5 mg");
}

// Working with predefined units
{
    QVariant!double distance = 384_400 * kilo(meter); // From Earth to Moon
    QVariant!double speed = 299_792_458 * meter / second; // Speed of light
    QVariant!double time = distance / speed;
    assert(time.siFormat!"%.3f s" == "1.282 s");
}

// Dimensional correctness
{
    import std.exception : assertThrown;

    QVariant!double mass = 4 * kilogram;
    assertThrown!DimensionException(mass + meter);
    assertThrown!DimensionException(mass == 1.2);
}

// Create a new unit from the predefined ones
{
    QVariant!double inch = 2.54 * centi(meter);
    QVariant!double mile = 1609 * meter;
    assert(mile.value(inch).approxEqual(63_346)); // inches in a mile
    // NB. Cannot use siFormatter, because inches are not SI units
}

// Create a new unit with new dimensions
{
    // Create a new base unit of currency
    QVariant!double euro = unit!double("C"); // C is the chosen dimension symol (for currency...)

    QVariant!double dollar = euro / 1.35;
    QVariant!double price = 2000 * dollar;
    assert(price.value(euro).approxEqual(1481)); // Price in euros
}

// Run-time parsing
{
    auto data = ["distance-to-the-moon" : "384_400 km", "speed-of-light" : "299_792_458 m/s"];
    QVariant!double distance = parseSI(data["distance-to-the-moon"]);
    QVariant!double speed = parseSI(data["speed-of-light"]);
    QVariant!double time = distance / speed;
}