We all love our scripting languages with its simplicity, elegant and beautiful syntax, and the ability to quickly hack together a solution. One of the common features of most scripting languages is being weakly typed. Meaning that we don’t have to declare the variable’s data type before we use it; to some developers this is a time saver and is one of the appeal of using these types of languages. But like with most things it has its pros and cons, and these are 5 things that you have to consider before using a weakly typed language.

1. Using them in a team is risky. Unless you have some kind of coding standards to determine what kind of type this variable is being used for, there is always a risk of somebody trampling on each others variables thereby causing side-effects all over the system.
2. Maintenance issues. Going back on an already completed system after some time to do maintenance work on bugs is a nightmare in any language. Weak typing exacerbates this situation because of the danger of lacking checks and balances on what a variable can handle.
3. Tool support. While the current state of IDE’s for scripting languages are improving. There is still work to be done especially on code assists, because of the nature of weak typing, this only partially works on some IDE’s.
4. Error catching. Scripting languages are almost always are interpreted at runtime, therefore most conversion errors are not caught since there is no compiler to catch this errors. Even if there is a compiler, type information are dynamically determined by the interpreter.
5. Performance/Optimizations. Statically typed languages have the advantage of having been optimized by the compiler. While interpreted languages are always a little bit slower than their compiled counterparts, dynamic typing and dynamic type conversions will always cause a little overhead.