* added defmacro!
* revert #924#924 had an error and should never have been merged in the first place. (see #903)
* put back import getargspec
Without the `formatargspec` this time.
* Give better error message on failed macro expansion
Better error messages work most of the time. In cases where there are
parameters that aren't valid in Python, error message shown is rather
ugly. But this is better than no error messages at all and such
macros with strange parameter names are rather rare.
* fix flake8 errors
* Minor English improvements
Per the straw poll in #908, as an alternative to #1147.
Now you must use `True`, `False`, and `None`, as in Python. Or just assign `true` to `True`, etc.; the old synonyms aren't reserved words anymore.
The `if` form now supports elif clauses.
It works like `cond` but without the implicit `do`.
The old `if` is now `if*`
variadic lif now supports "ellif" clauses.
Update if-no-waste compiler to use `if*` properly.
(Sometimes one character is all it takes.)
document if
reword truthiness
This changes let to use a flat list of symbol-value pairs instead of a
vector of vectors. One side effect is that (let [[a 1] z]) is not
expressible now, and one will explicitly need to set a nil value for z,
such as: (let [a 1 z nil]).
Closes#713.
Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>
A tribute to Portal 2, this function will return an infinite list of the
contents of the AUTHORS file on GitHub master (assuming requests is
installed). Except, the macro does this, the function never gets called,
it is purely there for tribute reasons.
Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>
Currently, defmacro/g! doesn't respond well when it comes across a
HyObject that doesn't respond to the instance method startswith (e.g.
HyInteger, HyFloat, etc.). This updates defmacro/g! to be a little
safer when searching for the gensyms it needs to create.
This also breaks out the PY3 only tests into their own file. We need to do this because raise from is a syntax error in PY2, so we can't rely on the previous hack of catching a HyCompileError - it would compile fine through Hy and then be a syntax error in Python.
The yield-from that existed previously wasn't actually implementing the
full complexity of "yield from":
http://legacy.python.org/dev/peps/pep-0380/#formal-semantics
... this includes passing along errors, and many other things.
Also removes the yield-from backport macro, since it does not seem
possible at present to conditionally build macros.
Thus, there is no longer yield-from on pre-python-3.3 systems.
Includes updated docs and tests to reflect all this.
One would expect the form:
> (defmacro a (&rest b) b)
> (a 1 2)
To return a tuple object but we have no Hy model so it returns a HyList.
Not sure if this is the right thing to do.
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>
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 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).
