Example:
(defmain [&rest args]
(print "now we're having a fun time!")
(print args))
Which outputs:
$ hy test.hy
now we're having a fun time!
(['test.hy'],)
Includes documentation and tests.
Sometimes it is better to start with the false condition, sometimes that
makes the code clearer. For that, the (if-not) macro, which simply
reverses the order of the condition blocks, can be of great use.
Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>
In the same vein as defmacro-alias, this implements defn-alias /
defun-alias, which does essentially the same thing as defmacro-alias,
but for functions.
Signed-off-by: Gergely Nagy <algernon@balabit.hu>
Added first iteration of reader macros
Refactored defmacro and defreader
Added test inn hy/tests/lex/test_lex.py
Added new test in hy/tests/native/tests
Added new test in hy/tests/macros.
changed the error given in the dispatch macro and added some handling for missing symbol and invalid characters
Adding to the manual gensym for macros are 2 new
macros, but very literal from the CL in
letoverlambda.
The first is the (with-gensyms ...) macro that
can generate a small set of syms for a macro. Works
something like:
(defmacro adder2 [A B]
(with-gensyms [a b]
`(let [[~a ~A] [~b ~B]]
(+ ~a ~b))))
and ~a and ~b will be replaced with (gensym "a") and
(gensym "b") respectively.
Then the final macro is a new defmacro that will automatically
replace symbols prefaced with "g!" with a new gensym based on the
rest of the symbol. So in this final version of 'nif':
(defmacro/g! nif4 (expr pos zero neg)
`(let [[~g!result ~expr]]
(cond [(pos? ~g!result) ~pos]
[(zero? ~g!result) ~zero]
[(neg? ~g!result) ~neg])))
all uses of ~g!result will be replaced with (gensym "result").
Simple implementation of gensym in Hy.
Returns a new HySymbol.
Usable in macros like:
(defmacro nif [expr pos zero neg]
(let [[g (gensym)]]
`(let [[~g ~expr]]
(cond [(pos? ~g) ~pos]
[(zero? ~g) ~zero]
[(neg? ~g) ~neg]))))
This addresses all the general comments about (gensym), and doesn't
try to implement "auto-gensym" yet. But clearly the macro approach
instead of the pre-processor approach (as described in the
letoverlambda (http://letoverlambda.com/index.cl/guest/chap3.html#sec_5)
is the way to go
This gets rid of the dichotomy between bootstrap.py and macros.hy,
by making both files hy modules.
I added some error checking to make the macros more resilient. The
biggest (user-visible) change is the change in cond, which now only
accepts lists as arguments. Tests updated accordingly.
Closes: #176 (whoops, no more bootstrap)
This will let us use (basic) yield from behavior from Python 2. This
isn't complete, and is low-hanging fruit for others willing to hack
on hy.
I've also changed the macrosystem to allow for proper bootstrapping.
This is similar to how it's done elsewhere in the codebase (stdlib
stuff).
