Major Section: SWITCHES-PARAMETERS-AND-MODES
Example: (table macro-aliases-table 'append 'binary-append)This example associates the function symbol
binary-append with the
macro name append. As a result, the name append may be used as a
runic designator (see theories) by the various theory functions. Thus, for
example, it will be legal to write
(in-theory (disable append))as an abbreviation for
(in-theory (disable binary-append))which in turn really abbreviates
(in-theory (set-difference-theories (current-theory :here)
'(binary-append)))
General Form:
(table macro-aliases-table 'macro-name 'function-name)
or very generally
(table macro-aliases-table macro-name-form function-name-form)where
macro-name-form and function-name-form evaluate, respectively,
to a macro name and a symbol in the current ACL2 world. See table for a
general discussion of tables and the table event used to manipulate
tables.Note that function-name-form (above) does not need to evaluate to a
function symbol, but only to a symbol. As a result, one can introduce the
alias before defining a recursive function, as follows.
(table macro-aliases-table 'mac 'fn)
(defun fn (x)
(if (consp x)
(mac (cdr x))
x))
Although this is obviously contrived example, this flexibility can be useful
to macro writers; see for example the definition of ACL2 system macro
defun-inline.The table macro-aliases-table is an alist that associates macro
symbols with function symbols, so that macro names may be used as runic
designators (see theories). For a convenient way to add entries to this
table, see add-macro-alias. To remove entries from the table with
ease, see remove-macro-alias.
This table is used by the theory functions; see theories. For example,
in order that (disable append) be interpreted as
(disable binary-append), it is necessary that the example form above has
been executed. In fact, this table does indeed associate many of the
macros provided by the ACL2 system, including append, with function
symbols. Loosely speaking, it only does so when the macro is ``essentially
the same thing as'' a corresponding function; for example, (append x y)
and (binary-append x y) represent the same term, for any expressions
x and y.
