MetaQuotes Language 4 (MQL4) is a programming language for developing trading robots, technical indicators, scripts, and function libraries for use on the MetaTrader 4 trading platform. Such applications significantly enhance traders' abilities when performing operations in the Forex market.
MetaQuotes Language 4 is a high-level object oriented programming language based on the concepts of the popular C++ programming language. The flexibility of the MQL4 language allows users to develop complex programs with large amount of calculations while accurately manage almost all trading robot and indicator parameters.
MQL4 contains the basic indicators necessary for analyzing current and historical quotes, and has built-in functions for managing trading orders. All these features of the MetaQuotes Language 4 allow creating applications that can perform operations in the Forex market and thus can completely replace a trader.
- A Trading Robot (Expert Advisor) is an application, which enables automated market analysis and Forex trading.
- A Custom Indicator is a tool for analyzing the market situation. Indicators do not perform trading operations. Contrary to built-in technical indicators, this kind of instruments can be programmed to execute any analytical algorithm.
- A Script is a small application that is executed once to perform a simple action. For example, a script can delete all objects from the chart, close all orders or place a number of pending orders for an open position.
- A Library is a set of custom functions. It is intended to store and distribute commonly used parts of custom applications.