Pool: The Swap Loop

Key takeaway: V3's swap is a while loop that walks price space. Each iteration finds the next initialized tick via the bitmap, clamps the step's target to whichever comes first — that tick's price or the caller's sqrtPriceLimitX96 — and lets computeSwapStep price the stretch. Ending a step exactly on a tick boundary triggers Tick.cross: the fee-growth-outside values flip, and liquidityNet (negated when moving down) adjusts the active liquidity before the next iteration. All working state lives in memory structs; storage is written once, after the loop. Settlement is pay-after-compute: send the output, demand the input inside uniswapV3SwapCallback, verify with a balance check ('IIA'). Every trade against the most-forked DEX engine in DeFi flows through the ~100 lines you are about to write.

What You Are Building

The full swap function. Everything the module has built so far was preparation: TickBitmap finds the ticks, SwapMath prices the stretches between them, Tick.cross rebalances liquidity at the boundaries, and the fee-growth machinery records who earned what. This section composes them. It is the longest function in the protocol and the hardest section of this module. Budget the time.