zl:1 - FTP

291
zl:let-closed
I
(let-and-make-dynamic-c1osure «a 5) b (c 'x»
(function (lambda () ... »)
macro-expands into
(let «a 5) b (c 'x»
(declare (special abc »
(make-dynamic-c1osure 'ea b c)
(funct ion (1 ambda 0 ... »»)
See the section "Dynamic Closure-Manipulating Functions" in Symbolics
Common Lisp: Language Concepts.
zl:let-closed ((variable value) ... ) function Special Form
When using dynamic closures, it is very common to bind a set of variables
with initial values, and then make a closure over those variables. Furthermore,
the variables must be declared as "special". zl:let-closed is a special
form that does all of this. It is best described by example:
(let-closed «a 5) b (c 'x»
(funct ion (1 ambda 0 ... »)
macro-expands into
(let «a 5) b (c 'x»
(declare (special abc »
(closure 'ea b c)
(functi on (1 ambda 0 ... »»)
The Symbolics Common Lisp equivalent of this function is
let-and-make-dynamic-closure. See the section "Dynamic Closure­
Manipulating Functions" in Symbolics Common Lisp: Language Concepts.
letf places-and-values body...
Special Form
Just like let, except that it can bind any storage cells rather than just variables.
The cell to be bound is specified by an access form that must be acceptable
to locf. For example, letf can be used to bind slots in a structure.
letf does parallel binding.
Given the following structure, letf calls do-something-to with ship's x
position bound to zero.