n. a model whereby forms are executed, returning zero or more values.
Such execution might be implemented directly in one step by an interpreter
or in two steps by first compiling the form and then
executing the compiledcode; this choice is
dependent both on context and the nature of the implementation,
but in any case is not in general detectable by any program. The evaluation
model is designed in such a way that a conforming implementation
might legitimately have only a compiler and no interpreter, or vice versa.
See Section 3.1.2 The Evaluation Model.
n. a point in a control form
from which (e.g., block),
through which (e.g., unwind-protect),
or to which (e.g., tagbody)
control and possibly values can be transferred both actively by using
another control form and passively through the normal control and
data flow of evaluation.
catch and block establish bindings for
exit points to which throw and return-from,
respectively, can transfer control and values;
tagbody establishes a binding for an exit point
with lexical extent to which go can transfer control;
and unwind-protect establishes an exit point
through which control might be transferred by
operators such as throw, return-from,
and go.
n. (of a variableV in a formF)
a reference to V that is directly apparent in the normal semantics of F;
i.e., that does not expose any undocumented details of the
macro expansion of the form itself.
References to V exposed by expanding subforms of F are, however,
considered to be explicit uses of V.
n. 1. an object, often used to emphasize the use
of the object to encode or represent information in a specialized
format, such as program text.
The second expression in a let form is a list
of bindings.
2. the textual notation used to notate an object in a source file.
The expression 'sample is equivalent to (quote sample).
