Unlike Python, Hy allows the programmer to intermingle positional and keyword arguments. This change removes an exception to that rule for method calls, in which the method callee always had to be the first thing after the method. Thus, `(.split :sep "o" "foo")` now compiles to `"foo".split(sep="o")` instead of `HyKeyword("sep").split("o", "foo")`.
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.
Give `require` the same features as `import`
You can now do (require foo), (require [foo [a b c]]), (require [foo [*]]), and (require [foo :as bar]). The first and last forms get you macros named foo.a, foo.b, etc. or bar.a, bar.b, etc., respectively. The second form only gets the macros in the list.
Implements #1118 and perhaps partly addresses #277.
N.B. The new meaning of (require foo) will cause all existing code that uses macros to break. Simply replace these forms with (require [foo [*]]) to get your code working again.
There's a bit of a hack involved in the forms (require foo) or (require [foo :as bar]). When you call (foo.a ...) or (bar.a ...), Hy doesn't actually look inside modules. Instead, these (require ...) forms give the macros names that have periods in them, which happens to work fine with the way Hy finds and interprets macro calls.
* Make `require` syntax stricter and add tests
* Update documentation for `require`
* Documentation wording improvements
* Allow :as in `require` name lists
This allows macros to take a keyword dict containing useful things by
defining a keyword argument. This allows us to pass in new objects
which might be handy to have in macros.
This changeset refactors module_name to become `compiler`, so that we
can pass the compiler itself into the macros as `opts['compiler']`.
This allows the macro to both get the macro name
(`compiler.module_name`), as well as use the compiler to build AST.
In the future, this will enable us to create "super-macros" which return
AST, not HyAST, in order to manually create insane things from userland.
For userland macros (not `defmacro`) the core.language `macroexpand`
will go ahead and make a new compiler for you.
This makes it possible to use strings as the macro name argument to
defreader, which in turn makes it possible to define reader macros with
names that would otherwise result in parse errors.
Such as `#.`.
This fixes#918.
Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>
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
Comparison operators such as =, !=, <, >, <=, >= should support a
one-arity version too, and return true in those cases (except for !=,
which returns false).
This closes#949.
Reported-by: Matthew Egan Odendahl
Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>
apply now mangles strings and keywords according to the Hy mangling
rules (by using the same function, now imported from
hy.lex.parser). With this change, if the dict passed to apply has
keywords, strings or quoted symbols, they'll get mangled, to turn them
into proper keys.
This only works for the cases where the keys are directly in the apply
params. A previously deffed dict, or key through a variable will not be
mangled.
This closes#219.
Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>
To make it easier to write --init-- functions, defclass will now check
any (setv) expressions (and its property list), to find any --init--
declarations, and append a nil to the end.
Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>
To mirror the behaviour of (setv), allow an empty (del) too: one that
shall return nil. Closes#905.
Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>
To allow classes to have methods that match built-in names, yet, still
disallow them outside of defclass, keep an internal state whether
builtins are allowed in the current context.
By default, this is false. But defclass will set it to True when it
compiles its body, and set it back to the previous value when it's done
with that. We need to set back to the previous value to allow nested
defclasses to work properly.
This closes#783.
Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>
Strip the \ufdd0 prefix from the keyword argument before turning it into
a string: the same representation the user entered looks better, and is
printable too, thus Python2 doesn't choke on it.
Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>
Some valid-looking list comprehensions, such as (genexpr x []) can crash
Python 2.7. The AST we generate from these cannot be expressed in
Python, but were valid in Hy.
Added two guards to guard against this, so we raise an error instead of
crashing Python.
Closes#572, #591 and #634.
Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>
When trying to setv a callable, raise an error instead of showing the
user an incredibly ugly backtrace. Closes#532.
Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>
defclass now has a new syntax:
(defclass Name [BaseList]
[property value
property value] ;; optional
(defn method [self]
self.property))
Anything after the optional property list (which will be translated to a
setv within the class context) will be added to the class body. This
allows one to have side effects and complex expressions within the class
definition.
As a side effect, defining methods is much more friendly now!
Closes#850.
Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>
Python 3 supports keyword-only arguments as described in the immortal
PEP 3102. This commit implements keyword-only argument support for Hy
using a `&kwonly` lambda-list-keyword with semantics analogous how
`&optional` arguments are handled: `&kwonly` arguments are either a
symbol, in which case the keyword argument so named is mandatory, or a
two-element list, the first of which is the symbolic name of the keyword
argument and the second of which is its default value if not
supplied. If Hy is running under Python 2, attempting to use `&kwonly`
args will raise a HyTypeError.
This effort is with the aim of resolving #453.
Python 3.5's PEP 448 ("Additional Unpacking Generalizations") allows the
iterable- and dictionary- unpacking operators to be used more than once;
the implementation (see https://hg.python.org/cpython/rev/a65f685ba8c0)
gets rid of the optional `starargs` and `kwargs` arguments to `ast.Call`
and `ast.ClassDef`, instead using `ast.Starred` and `ast.keyword`
objects inside of the normal `args` and `keywords` lists,
respectively. This commit allows Hy's `apply` to work correctly with
this revised AST when running under Python 3.5.
As reported in issue #748, there was a bug in which passing a lambda
as the value of a :keyword argument would fail—
$ hy --spy
hy 0.10.1 using CPython(default) 3.4.0 on Linux
=> (sorted (range 10) :key (fn [x] (- x)))
from hy.core.language import range
sorted(range(10), key=_hy_anon_fn_1)
Traceback (most recent call last):
File "<input>", line 1, in <module>
NameError: name '_hy_anon_fn_1' is not defined
The function call would appear in the generated AST without being
preceded by the appropriate function definition corresponding to the
anonymous function argument value in the Hy source, causing either a
NameError (as in the example above), or erroneous reuse of whatever
function was already pointed to by the `_hy_anon_fn_` name referenced
in the list of keywords passed to `ast.Call`.
This commit aims to fix the problem by handling it in same way that
the expression/statement gap is bridged many other places in the
compiler, by adding the compiled value of the keyword argument to the
Result object being built during `_compile_collect`, with the
understanding that any Python statements implied by the argument value
will be appropriately preserved therein.
Python 3.5 will have a new commercial-at infix operator with the magic
methods __matmul__, __rmatmul__, and __imatmul__, unused as yet in the
standard library, but intended to represent matrix multiplication in
numerical code; see PEP 465 (https://www.python.org/dev/peps/pep-0465/)
for details. This commit (developed against Python 3.5 alpha 3) brings
support for this operator to Hy when running under Python 3.5 (or,
hypothetically as yet, greater). For Hy under Python <= 3.4, attempting
to use `@` in function-call position currently results in a NameError;
this commit does not change that behavior.
This is intended to resolve#668.
jcrocholl/pep8 (used by flake8, used in Hy's continuous integration
builds) introduced an imports-at-top-of-file check in 1.6.0 and a
line-breaks-around-binary-operators check in 1.6.2. This commit makes
nonfunctional changes to bring the Hy codebase in compliance with this
tool, fixing #764.
This code is heavily, *heavily* based off of Guillermo Vaya
(willyfrog)'s work... instead of defining its own keyword arg though, it
uses the "standard" :kwarg type, which is the main difference from
willyfrog's original branch.
Included tests and some documentation in the tutorial.
Also documented "apply" separately as an example of reproducing
*args and **kwargs.
When (fn) or (defn) does not get an arglist as first/second parameter,
emit a more descriptive error message, rather than an ugly traceback.
Fixes#716.
Reported-by: Joakim Tall
Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>
Python has the keyword.iskeyword method we can leverage for Python
keywords, but we also need to address Hy builtins like 'get' or
'slice'.
And to make behavior compatible with Python 2 or 3, we also make
a special case to prevent assignment to False, True or None as
well as the Hy versions: false, true, null, and nil.
For non-Hy modules, we also check to make sure the symbol is not
part of the compiler. This allows shadow.hy to override "+" but
prevents general use from re-defn-ing 'get' or 'do'.
As noted in #600, Python 3 allows a return inside a generator
method, that raises a StopIteration and passes the return value
inside the 'value' attr of the exception.
To allow this behaviour we simple set 'contains_yield' while compiling
'yield', thus allowing a return statement, but only for Python 3. Then
when compiling the try-except, we check for contains_yield to decide
whether there will be a return.
This allows code like:
(defn gen []
(yield 3)
"goodbye")
to compile in both Py2 and Py3. The return value is simply ignored in
Python 2.
hy2py in Python 2 gives:
def g():
yield 3L
u'goodbye'
while hy2py in Python 3 gives:
def g():
yield 3
return 'goodbye'
Turns out return in yield started in Python 3.3
Also small DRYing in try handling.
Previously, writing a bare (try (foo)) would invoke Pokemon
exception catching (gotta catch 'em all) instead of the correct
behavior, which is to raise the exception if no handler is provided.
Note that this is a cute feature of Hy, as a `try` with no `except`
is a syntax error. We avoid the syntax error here because we don't
use Python's compiler, which is the only thing that can throw
Syntax Errors. :D
Fixes#555.
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.
When (import) encounters anything but a HySymbol or HyList, raise an
exception, as that is not valid in Hy. Previously, anything other than a
HySymbol or HyList was simply ignored, turning that particular import
into a no-op, which was both wrong and confusing.
Reported-by: Richard Parsons <richard.lee.parsons@gmail.com>
Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>
This version is much simpler.
At the point that the exception is raised, we don't have access to
the actual source, just the current expression. but as the
exception percolates up, we can intercept it, add the source and
the re-raise it.
Then at the final point, in the cmdline handler, we can choose to
let the entire traceback print, or just the simpler, direct error
message.
And even with the full traceback, the last bit is nicely formatted
just like the shorter, simpler message.
The error message is colored if clint is installed, but to avoid
yet another dependency, you get monochrome without clint.
I'm sure there is a better way to do the markup, the current method
is kludgy but works.
I wish there was more shared code between HyTypeError and LexException
but they are kind of different in some fundamental ways.
This doesn't work (yet) with runtime errors generated from Python,
like NameError, but I have a method that can catch NameError and turn it
into a more pleasing output.
Finally, there is no obvious way to raise HyTypeError from pure Hy code,
so methods in core/language.hy throw ugly TypeError/ValueError.
When calling get with more than two arguments, treat the rest as indexes
into the expression from the former. That is, (get foo "bar" "baz")
would translate to foo["bar"]["baz"], and so on.
This fixes#362.
Requested-by: Sean B. Palmer <sean@miscoranda.com>
Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>
Apply didn't work on method calls (i.e. `(apply .foo [bar]) broke).
This slipped through because there were no tests of this behavior. I noticed
it while trying to merge the `meth` fixes.
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
Like other lisps, operators `+` and `*` return their identity values
when called with no arguments. Also with a single operand they return
the operand.
This fixes#372
There was a couple of duplicate imports and type checkings in the
codebase. So I added a new module to unify all Python 2 and 3
compatibility codes.
Also, this is a somewhat common pattern in Python. See Jinja2 for
example:
https://github.com/mitsuhiko/jinja2/blob/master/jinja2/_compat.py
This adds a class to avoid returning when we have a Yieldable
expression contained in the body of the function. This breaks Python
2.x, and ought to break Python 3.x, but doesn't.
We need this fo' context managers, etc.
This commit also has work from @rwtolbert adding new testcases and
fixes for yielded entries behind a while / for.
Add set of new core functions to the stdlib.
Moved the auto-import code from compile_expression to
HySymbol so that "even?' in this style expression will
be found and imported.
(list (filter even? [1 2 3 4 5]))
The core functions are documented in 2 sections, one
for basic functions like (even?..) and (nth ...) and
one for all the sequence functions.
Update: This removes all the caching decorators, misnamed as
'lazy-seq' from the core. All sequence methods now just use
yield to return a generator, so they are Python-lazy
Further refinements of core functions
Cleaned up the docs to use 'iterator' instead of 'generator'
Fixed drop to just return the iterator instead of an extra
yield loop. But also added a test to catch dropping too
many.
This will let us implement common functions seen in other lisps,
and allow them to be importable, without explicit imports. The goal
is to keep this as small as we can; we don't want too much magic.
I've added `take' and `drop' as examples of what we can do.
