MetaQuotes Language 4 (MQL4) is a language used in the MetaTrader 4 online-trading terminal software for programming trading strategies. This language allows the creation of Expert Advisors that make trading management automated and are perfectly suitable for implementation of trade strategies. Also, MQL4 can be used for the creation of Custom Indicators, Scripts, and Libraries.
MetaQuotes Language 4 (MQL4) is a domain-specific language for programming of trading strategies built in to a MetaTrader Terminal — a client-side trading app.
This language allows one to create "Expert Advisors" that make visualisations and trading management augmented/automated and are perfectly suitable for implementation of trade strategies.
MQL4 can also be used for the creation of "Custom Indicators", "Scripts", "Libraries", and more complex, distributed/grid processing solutions.
The structure and syntax of the language is very similar to C.
MQL4, introduced in about 2012, added new concepts borrowed from the not-so-widely accepted MQL5 domain, and legacy MQL4 codes started to have two different compilation/execution modes, depending on a use of a #property strict directive. Also some internalities of the MetaTrader Terminal platform started to be changed, resulting in a need to massively redesign/re-engineer the code-base, due to injected changes (having no other option but to re-design DLL interfaces and much more - e.g., the string type ceased to be a string - but a NULL terminated block of chars).
Check further details at: http://www.mql4.com/
MetaQuotes' head of sales at the time, Anthony Papaevagorou, announced that MetaQuotes no longer intends to issue upgrades to the MetaTrader 4 (MT4), as reported on 2016-11-15.
