Chapter 3. Naming Conventions

Names are but noise and smoke, Obscuring heavenly light

—Johann Wolfgang von GoetheFaust: Part I

Consistent and coherent code layout is vital, because it determines what the reader of your code sees. But naming conventions are even more important, because they determine how the reader thinks about your program.

Well-chosen identifier names convey to the reader the meaning of the data in variables, the behaviour and results of subroutines, and the features and purpose of classes and other data types. They can help to make the data structures and algorithms used in a program explicit and unambiguous. They can also function as a reliable form of documentation, and as a powerful debugging aid.

Best practice in naming consists of finding a consistent way of assigning identifiers to variables, subroutines, and types. There are two principal components of this method: syntactic consistency and semantic consistency.

Syntactic consistency means that all identifiers should conform to a predictable and recognizable grammatical structure. That is, you should not name one variable $max_velocity and then name another $displacementMax, or $mxdsp, or $Xmaximal. In other words, if one variable name has an adjective_noun structure, all variable names should be adjective_noun. Similarly, if one variable uses underscores to separate components of the name, then others shouldn't omit similar separators elsewhere, or use interCapStyle instead. Your approach to abbreviation—both ...

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