Before continuing, let’s review how computer programs get made. If you’re coming to Xcode from long experience with GNU Make or another development environment, this discussion will be extremely familiar to you.
Programmers use source code to specify what a program does; source code files contain a notation that, although technical and sometimes cryptic, is recognizably the product of a human, intended in part for humans to read and understand. Even the most precise human communication leaves to allusion and implication things that a computer has to have spelled out. When the
Linrg tool refers to the local variable
slope, for example we cared only that the name
slope should consistently refer to the result of ...