context/1 — The Logtalk Handbook v3.47.0 documentation

# `context/1`

## Description

    context(Context)

Returns the execution context for a predicate clause using the term `logtalk(Head,ExecutionContext)` where `Head` is the head of the clause containing the call. This private predicate is mainly used for providing a default error context when type-checking predicate arguments. The `ExecutionContext` term should be regarded as an opaque term, which can be decoded using the logtalk::execution_context/7 predicate. Calls to this predicate are inlined at compilation time.

## Modes and number of proofs

    context(--callable) - one

## Errors

`Context` is not a variable:
`type_error(var, Context)`

## Examples

    foo(A, N) :-
        % type-check arguments
        context(Context),
        type::check(atom, A, Context),
        type::check(integer, N, Context),
        % arguments are fine; go ahead
        ... .

See also

parameter/2, self/1, sender/1, this/1