Expressions can sometimes contain itertools.islice objects, which we can
only walk if we force them into a list. To do this, the walk function
has to be taught that collections that are not instances of list should
be forced into a list.
Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>
This function will recursively perform all possible macroexpansions in
the supplied form. Unfortunately, it also traverses into quasiquoted
parts, where it shouldn't, but it is a useful estimation of macro
expansion anyway.
Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>
The hy.contrib.walk module provides a few functions to walk the Hy AST,
and potentially transform it along the way. The main entry point
is (walk), which takes two functions and a form as arguments, and
applies the first (inner) function to each element of the form, building
up a data structure of the same type as the original. Then applies outer
(the second function) to the result.
Two convenience functions are provided: (postwalk) and (prewalk), which
do a depth-first, post/pre-order traversal of the form.
Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>
* hy/contrib/anaphoric.hy: The following anaphoric macros have been
added
`ap-reject` : Opposite of ap-filter, yields the elements when a `pred`
evaluates to false
`ap-dotimes` : Execute body forms (possibly for side-effects) n times
with `it` bound from 0 to n-1
`ap-first` : return the first element that passes predicate
`ap-last` : return the last element that passes predicate
`ap-reduce`: anaphoric form of reduce that allows `acc` and `it` to
create a function that is applied over the list
* docs/contrib/anaphoric.rst: updated docs to reflect these changes
* tests/__init__.py: updated to explicitly include tests for anaphoric
macros
