Terms and Definitions
For the purposes of this document, the following terms and definitions apply:
- argument
- a value passed to a function, that is intended to map to a corresponding parameter.
- behavior
- external appearance or action.
- behavior, implementation-defined
- behavior specific to an implementation, where that implementation must document that behavior.
- behavior, undefined
- behavior which is not guaranteed to produce any specific result. Usually follows an erroneous program construct or data.
- behavior, unspecified
- behavior for which this specification provides no requirements.
- constraint
- restriction, either syntactic or semantic, on how language elements can be used.
- error, fatal
- a condition in which the engine cannot continue executing the script and must terminate.
- error, fatal, catchable
- a fatal error that can be caught by a user-defined handler.
- error, non-fatal
- an error that is not a fatal error and allows for the engine to continue execution.
- lvalue
- an expression that designates a location that can store a value.
- lvalue, modifiable
- an lvalue whose value can be changed.
- lvalue, non-modifiable
- an lvalue whose value cannot be changed.
- notice
- an informational message informing user of the code that may not work as intended.
- parameter
- a variable declared in the parameter list of a function that is intended to map to a corresponding argument in a call to that function.
- PHP Run-Time Engine
- the software that executes a PHP program. Referred to as the Engine throughout this specification.
- value
- a primitive unit of data operated by the Engine having a type and potentially other content depending on the type.
Other terms are defined throughout this specification, as needed, with the first usage being typeset like this.