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https://github.com/guicho271828/aspectm
aspect-oriented hooks
https://github.com/guicho271828/aspectm
Last synced: 29 days ago
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aspect-oriented hooks
- Host: GitHub
- URL: https://github.com/guicho271828/aspectm
- Owner: guicho271828
- Created: 2015-03-20T15:04:36.000Z (almost 10 years ago)
- Default Branch: master
- Last Pushed: 2017-10-20T03:22:42.000Z (about 7 years ago)
- Last Synced: 2024-10-15T14:11:00.988Z (3 months ago)
- Language: Common Lisp
- Homepage:
- Size: 23.4 KB
- Stars: 1
- Watchers: 3
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.org
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README
* Aspectm - control macroexpand hooks
=*macroexpand-hook*= in Common Lisp is quite hard to maintain correctly,
since it is global and anyone can modify its value. This library is an
experimental attempt to provide a set of "acceptable" way of modifying the
hook. Well, I feel, kind of defeated.
AspectM provides CLOS-like /around/, /before/, /after/ hooks for
macroexpansion, and I planned to implement useful hooks based upon this system.
#+BEGIN_SRC lisp
(enable-macroexpand-hooks) ; enable around hooks, then
(add-around-hook 'standard-hook) ; register standard (=before+after) hook as an around hook
;; expanded before the main expansion, then prepended to the main expansion result
(defmacro force-inline (&whole form name args &body body)
(assert (eq 'defun (car form)))
`(declaim (inline ,name)))
(set-standard-hook 'defun 'force-inline :before)
(macroexpand
`(defun my-+ (x y) (+ x y)))
(remove-standard-hook 'defun 'force-inline :before)
;; there are also with-standard-hook
#+END_SRC
# Note: *ABOVE CODE DOES NOT WORK.*
I want the scope of these hooks to be file local, but not sure how.
This is the main reason I stopped the development.
# Sounds simple, but actually not. The main problem is about the invalidation
# of the compilation results, and the scope of the hook. What happends if we put a hook
# =set-standard-hook= in file A, which is loaded before a file B that
# contains =my-+= above, but the file B is already compiled? What if a user
# forgot adding =remove-standard-hook= in the end of file B? It affects every
# single file loaded after it. Well, this might be a matter of ASDF system
# definition, but there are various similar effects.
#
# The scope of a hook is package. Each enable-macroexpand-hooks remembers its
* Details
/around/ hooks are always nested, and I suppose this is the expected usage of
=*macroexpand-hook*=. Notable difference is that
every /around/ hooks MUST call the next hook by calling =(call-next-hook)=,
or it signals an compile-time error. This ensures that all hooks are called
in the right order without skipping/overriding.
Based on this system, AspectM implements a set of hooks
called /standard/ hooks, which consist of /before/ and /after/ hooks,
just like /before/ and /after/ methods in CLOS.
The functionalities of before/around hooks follow:
+ It can see the arguments of the macro.
+ It can prepend/append forms to the main form returned by the macro, each wrapped in progn.
+ However it cannot modify the main expansion result.
Expected usecases: Side-effects upon expansion. E.g. exporting symbols,
proclaim =inline=, or storing the form as a workaround for a system that
does not provide =function-lambda-expression=.
Unfortunately, =load= and =compile= does *not* rebind =*macroexpand-hook*=
as they do for =*readtable*= and =*package*=. You are warned.
* Setting a Standard Hook
/before/ and /after/ hooks are regular macro-functions of two arguments
(the form and environment). The example code below automatically adds
=inline= proclaration to all =defun=-ed function.
#+BEGIN_SRC lisp
(defmacro force-inline (&whole form name args &body body)
(assert (eq 'defun (car form)))
`(declaim (inline ,name)))
(set-standard-hook 'defun 'force-inline :before)
#+END_SRC
* Dependencies
This library is at least tested on implementation listed below:
+ SBCL 1.2.8 on X86-64 Linux 3.13.0-46-generic (author's environment)
Also, it depends on the following libraries:
+ alexandria by ::
Alexandria is a collection of portable public domain utilities.
+ lisp-namespace by Masataro Asai ::
Provides LISP-N --- extensible namespaces in Common Lisp.
* Copyright
Copyright (c) 2015 Masataro Asai ([email protected])
* License
Licensed under the LLGPL License.