File with a .P extension contains source code of a program stored in the Pascal procedural programming language, a different, more common extension for files containing this type of code is .PAS. Pascal programming language was developed by Niklau Wirth in the end of 1960s and it is used until today as an example of a structural language for coding beginners.

P files can be opened and edited both in programming environments and in a simple text editor. After compiling with a proper compiler, for instance TurboPascal, an executable program is being created. Pascal language was further developed, for instance into Sol or Super Pascal, and an object-based language based on the semantics of Pascal is the Object Pascal.