History of MQL5.community development

Learn how to build an MQL5 Expert Advisor that detects and trades Larry Williams’ Oops Gap Reversal pattern using objective gap rules and later-bar confirmation. The EA tracks setup expiration, prepares stop-loss and take-profit levels, supports manual or risk-based position sizing, executes market orders, and is evaluated through historical testing.

An MQL5 analyzer reconstructs completed trades, records acceptance labels, and measures the accepted-minus-rejected mean net-profit difference. It benchmarks that statistic against individual permutations, equal-block permutations, and circular shifts while preserving the accepted count. Block-size sensitivity, CSV exports, and coordinated base/filtered passes separate statistical selection evidence from operational effects on profit, drawdown, and efficiency metrics.

This article presents CSwingEngine, a reusable MQL5 class that detects H4 swing highs and lows, labels them HH, LH, HL, or LL, and classifies market structure as trend or range. Swings are always computed on H4, regardless of the attached chart, and each point draws correctly on lower timeframes via native datetime anchoring. The engine exposes a clean interface to query the current trend and retrieve the swing array for context-aware pattern logic.

This article presents a compact MQL5 library for market-complexity analysis: LZ76 complexity and Normalized Compression Distance built on a SAX symbolizer, exposed through a simple facade and an efficiency indicator. It explains the discretization choices, normalization, and distance formulation, and validates the code with unit checks and an independent cross-check. You get a ready-to-use library and indicator, plus a disciplined way to interpret readings with a shuffle null and a direction check.

A naive MQL5 port of trend-scanning features recomputes each candidate window per bar at O(H·L) cost. This article introduces CTrendScanningFeatures.mqh, which maintains three running sums per horizon and updates them in O(1) per bar, verified against a Python reference. The indicator exposes four causal buffers - window, slope, t_value, rsquared - at the confirmation bar and corrects a sign inversion present in the original backward labeling mode.

This article implements an online logistic‑regression trade filter in native MQL5 and integrates it into an EMA‑crossover EA with a closed‑trade feedback loop. It details the shared class, features, SGD update, persistence, and a read‑only probability view. Synthetic experiments cover multi‑seed separation, calibration, feature ablation, regime‑shift baselines, and hyperparameter sweeps. You get reproducible scripts and a walk‑forward protocol to validate the filter on your own instrument.

This MQL5 engine applies configurable profit ladders in R‑multiples to manage partial closes reliably. It prevents stranded remainders by rounding to lot step, computes close percentages from the original entry volume, and moves the stop to breakeven when configured. A supported filling mode is chosen automatically, and the download includes seven include files, a demo EA, and a verification script.

This article is a practical walk-through of the MetaEditor debugger using a rolling z‑score indicator with two planted bugs: an off‑by‑one array access and a silent wrong‑denominator variance. We show how to set breakpoints, step through code, read the call stack, and inspect values in the Watch window. You will learn a repeatable method to catch both crashing index errors and tiny numerical biases that charts cannot reveal.