Major Section: SWITCHES-PARAMETERS-AND-MODES
Examples:
(set-ld-keyword-aliases '((:q 0 q-fn)
(:e 0 exit-acl2-macro))
state)
(ld-keyword-aliases state) ; current value of the ld-keyword-aliases table
Ld-keyword-aliases is the name of a ACL2 table (see table) and also the
name of a function of state that returns the value of this table. That
value must be an alist, each element of which is of the form
(:keyword n fn), where :keyword is a keyword, n is a nonnegative
integer, and fn is a function symbol of arity n, a macro symbol, or a
lambda expression of arity n. When keyword is typed as an
ld command, n more forms are read, x1, ..., xn, and the form
(fn 'x1 ... 'xn) is then evaluated. The initial value of the
ld-keyword-aliases table is nil.ACL2 provides functions to modify the ld-keyword-aliases table, as
follows.
(Set-ld-keyword-aliases val state): sets the table toval, which must be a legal alist as described above. This is an event that may go into a book (see events), but its effect will be local to that book.
Set-ld-keyword-aliases!is the same asset-ld-keyword-aliases, except that its effect is not local. Indeed, the form(set-ld-keyword-aliases val state)is equivalent to the form(local (set-ld-keyword-aliases! val state).
(Add-ld-keyword-alias key val state): modifies the table by binding the keywordkeytoval, which must be a legal value as described above. This is an event that may go into a book (see events), but its effect will be local to that book.
Add-ld-keyword-alias!is the same asadd-ld-keyword-alias, except that its effect is not local. Indeed, the form(add-ld-keyword-alias key val state)is equivalent to the form(local (add-ld-keyword-alias! key val state).
Consider the first example above:
(set-ld-keyword-aliases '((:q 0 q-fn)
(:e 0 exit-acl2-macro))
state)
With this event, :q is redefined to have the effect of executing
(q-fn), so for example if you have defined q-fn with
(defmacro q-fn () '(er soft 'q "You un-bound :q and now we have a soft error."))then
:q will cause an error, and if you have defined
(defmacro exit-acl2-macro () '(exit-ld state))then
:e will cause the effect (it so happens) that :q normally
has. If you prefer :e to :q for exiting the ACL2 loop, you
might even want to put such definitions of q-fn and exit-acl2-macro
together with the set-ld-keyword-aliases form above into your
"acl2-customization.lsp" file; see acl2-customization.
The general-purpose ACL2 read-eval-print loop, ld, reads forms from
standard-oi, evaluates them and prints the result to standard-co.
However, there are various flags that control ld's behavior and
ld-keyword-aliases is one of them. Ld-keyword-aliases affects how
keyword commands are parsed. Generally speaking, ld's command
interpreter reads ``:fn x1 ... xn'' as ``(fn 'x1 ... 'xn)'' when
:fn is a keyword and fn is the name of an n-ary function;
see keyword-commands. But this parse is overridden, as described above, for
the keywords bound in the ld-keyword-aliases table.