Hands-On Design Patterns and Best Practices with Julia

Designing parametric methods

In order to fully utilize the compiler's specialization feature, we should define parametric methods that also make use of the parametric type, like so:

# Return + or - sign for the direction of tradefunction sign(t::SingleTrade{T}) where {T}     return t.type == Long ? 1 : -1end# Calculate payment amount for the tradefunction payment(t::SingleTrade{T}) where {T}     return sign(t) * t.quantity * t.priceend

Let's test this out:

But hey, we just found a little bug. The option of $3.50 seems too good to be true! When looking at buying/selling options, each option contract actually represents 100 shares of the underlying ...