Context refers to the execution context, which is the symbols reachable from a given point in the code, and the value of those symbols in that particular execution.
Context is an important concept because:
- Executable units (functions, procedures, instructions) may produce different results or behave differently under different contexts.
- The larger or more complex the context, the more difficult to understand what a piece of code does (that's why global variables are shunned upon).
You do not have to write context classes or pass context parameters. Any parameter passed to a function/method becomes part of the execution context when it is invoked.
Even though you're not an English speaker, I recommend you go through a copy of Code Complete for a gentle yet thorough introduction to concepts like context, modularity, coupling, cohesion, and so forth.
