Larry Williams Oops Gap Reversal Expert Advisor

An MQL5 Expert Advisor that detects and trades Larry Williams' Oops gap reversal pattern in MetaTrader 5.

The EA identifies qualifying gap-up and gap-down setups, tracks one active setup for a limited number of bars, confirms the reversal using a completed candle, calculates the stop loss, take profit, and position size, and validates the trade-server response before reporting success.

This repository supports the MQL5 article:

Larry Williams Market Secrets (Part 16): Detecting and Trading the Oops Gap Reversal Pattern

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Purpose

The Oops pattern is simple to describe, but applying it consistently requires several decisions:

• Whether the opening gap is large enough
• How long the setup should remain active
• Whether price has returned into the previous range
• Where the stop loss should be placed
• How the take profit should be calculated
• What trade volume should be used
• Whether another EA-managed position is already open
• Whether the trade server accepted the order request

This Expert Advisor converts those decisions into explicit MQL5 rules that can be compiled, inspected, and tested in the MetaTrader 5 Strategy Tester.

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Strategy Rules

Bullish setup

A bullish Oops setup requires:

1. The current bar opens below the previous bar's low.
2. The gap is at least minimumGapSizePoints.
3. The setup remains within maxGapValidityBars.
4. A later completed candle closes at or above the stored previous low.

The EA then prepares a buy trade.

• Entry reference: current Ask price
• Stop loss: low of the original gap bar
• Take profit: entry price plus the risk distance multiplied by riskRewardRatio

Bearish setup

A bearish Oops setup requires:

1. The current bar opens above the previous bar's high.
2. The gap is at least minimumGapSizePoints.
3. The setup remains within maxGapValidityBars.
4. A later completed candle closes at or below the stored previous high.

The EA then prepares a sell trade.

• Entry reference: current Bid price
• Stop loss: high of the original gap bar
• Take profit: entry price minus the risk distance multiplied by riskRewardRatio

Confirmation method

This implementation uses closed-bar confirmation.

The gap bar cannot confirm itself. A later completed candle must close through the stored previous-range boundary before the EA generates a signal.

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Main Features

• Gap-up and gap-down detection
• Configurable minimum gap size
• Configurable setup validity window
• Closed-bar reversal confirmation
• Persistent setup state across ticks and bars
• Stop loss based on the original gap bar
• Risk-reward-based take-profit calculation
• Manual position sizing
• Percentage-risk-based position sizing
• Broker volume-limit handling
• Long-only, short-only, or both-direction modes
• One EA-managed position at a time
• Checked symbol-property access
• Checked candle-data access
• Checked position-property access
• Checked OrderCalcProfit() result
• Trade-server return-code validation
• Runtime diagnostics in the Experts log
• Visual and historical Strategy Tester support

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Requirements

• MetaTrader 5
• MetaEditor
• Historical data for the selected symbol and timeframe
• A demo account or Strategy Tester environment for testing

No external libraries are required.

The EA uses the standard MQL5 trading library:

#include <Trade\Trade.mqh>