This chapter has focused on things that we can see when we look at code in a code review situation. Such observations are necessarily somewhat subjective and open to disagreement. Another approach to the problem of analyzing code is to use a static analysis tool. Static analysis tools read the source code and apply a set of rules to determine places that the rules are broken. A report from such a tool gives very quick input into the quality of the code.

Some languages have a long history of static analysis tools. The C language, for example, has lint. If you're using C#, you have probably heard of StyleCop and FxCop. PowerShell has two static analysis tools: ScriptCop and Script Analyzer.