There are 4 utilities.
- letf* v1.0
Given a list of
bindingswhose keys are places and whose values are forms, set them for the duration of
body, but restore their values (as visible upon evaluation of this macro) upon completion. The restoration is ensured with
- zip, appendf
- let1 v1.0
Bind VAR to VAL within BODY. Equivalent to LET with one binding.
- if-let v1.0
Creates new variable bindings, and conditionally executes either
bindingsmust be either single binding of the form:
or a list of bindings of the form:
((variable-1 initial-form-1) (variable-2 initial-form-2) ... (variable-n initial-form-n))
All initial-forms are executed sequentially in the specified order. Then all the variables are bound to the corresponding values.
If all variables were bound to true values, the
then-formis executed with the bindings in effect, otherwise the
else-formis executed with the bindings in effect.