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Diffstat (limited to 'stdlib/except.tl')
| -rw-r--r-- | stdlib/except.tl | 88 |
1 files changed, 88 insertions, 0 deletions
diff --git a/stdlib/except.tl b/stdlib/except.tl new file mode 100644 index 00000000..60f2fe51 --- /dev/null +++ b/stdlib/except.tl @@ -0,0 +1,88 @@ +;; Copyright 2015-2021 +;; Kaz Kylheku <kaz@kylheku.com> +;; Vancouver, Canada +;; All rights reserved. +;; +;; Redistribution and use in source and binary forms, with or without +;; modification, are permitted provided that the following conditions are met: +;; +;; 1. Redistributions of source code must retain the above copyright notice, this +;; list of conditions and the following disclaimer. +;; +;; 2. Redistributions in binary form must reproduce the above copyright notice, +;; this list of conditions and the following disclaimer in the documentation +;; and/or other materials provided with the distribution. +;; +;; THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND +;; ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED +;; WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE +;; DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE +;; FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +;; DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR +;; SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER +;; CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, +;; OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +;; OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +(defun sys:handle-bad-syntax (item) + (throwf 'eval-error "~s: bad clause syntax: ~s" 'handle item)) + +(defmacro usr:catch (:form form :env e try-form . catch-clauses) + (let ((catch-syms [mapcar car catch-clauses]) + (sys-catch-clauses (mapcar (do mac-param-bind @1 (type args . body) @1 + (tree-bind (args-ex . body-ex) + (sys:expand-params args body + e nil form) + ^(,type (,(gensym) ,*args-ex) ,*body-ex))) + catch-clauses))) + ^(sys:catch ,catch-syms ,try-form nil ,*sys-catch-clauses))) + +(defmacro catch* (try-form . catch-clauses) + (let ((catch-syms [mapcar car catch-clauses])) + ^(sys:catch ,catch-syms ,try-form nil ,*catch-clauses))) + +(defmacro catch** (:env menv try-form . catch-clauses) + (let ((catch-syms [mapcar car catch-clauses]) + sys-catch-clauses descs) + (each ((cl catch-clauses)) + (mac-param-bind cl (type desc args . body) cl + (push ^(,type ,args ,*body) sys-catch-clauses) + (push desc descs))) + (sys:setq sys-catch-clauses (nreverse sys-catch-clauses)) + (sys:setq descs (nreverse descs)) + (let ((desc-expr (if [all descs (op constantp @1 menv)] + ^'(,*[mapcar eval descs]) + ^(list ,*descs)))) + ^(sys:catch ,catch-syms ,try-form ,desc-expr ,*sys-catch-clauses)))) + +(defun sys:expand-handle (form try-form handle-clauses) + (let* ((oper (car form)) + (exc-sym (gensym)) + (exc-args (gensym)) + (syms-fragments (collect-each ((hc handle-clauses)) + (tree-case hc + ((name arglist . body) + (unless (symbolp name) + (sys:handle-bad-syntax hc)) + (list name ^(apply (lambda ,arglist ,*body) + ,*(if (or (eq oper 'handle*) + (and (plusp sys:compat) + (<= 161 sys:compat))) + ^(,exc-sym)) + ,exc-args))) + (else (sys:handle-bad-syntax hc)))))) + ^(handler-bind (lambda (,exc-sym . ,exc-args) + (cond + ,*(mapcar (aret ^((exception-subtype-p ,exc-sym ',@1) ,@2)) + syms-fragments))) + ,[mapcar car syms-fragments] + ,try-form))) + +(defmacro handle (:form form try-form . handle-clauses) + (sys:expand-handle form try-form handle-clauses)) + +(defmacro handle* (:form form try-form . handle-clauses) + (sys:expand-handle form try-form handle-clauses)) + +(defmacro ignwarn (. forms) + ^(handler-bind (lambda (exc-sym . args) (throw 'continue)) (warning) ,*forms)) |