Time in force

Good-til-cancelled (GTC) orders require a specific cancelling order and can persist indefinitely (or can be limited by say 90 days).

Immediate or cancel (IOC) orders are immediately executed or cancelled by the exchange. Unlike Fill-or-Kill orders, IOC orders allow for partial fills.

Limit Order + IOC option

# Pseudocode
while order_filled < V and there are counter-orders:
    find counter-order with best_price
    if best_price is equal or better than P:
        fill the order
    else:
				break
update balances in quote and base tokens

How it is implemented on Flex:

Price contract needs to support these types of execution flags.