[REBOL] Re: A hard question
From: lmecir:mbox:vol:cz at: 5-Feb-2001 21:54
Hi all,
Frank solved my problem, and that is why I am able to generalize his
solution and have:
soft-func: function [
{Create a "soft return" function}
spec [block!]
body [block!]
] [modified-spec do-body thr-on fnc-return] [
modified-spec: head insert/only copy spec "Soft"
use [thr fnc] [
thr-on: does [thr: on]
fnc-return: func [[throw] fnc-result [any-type!]] [
either thr [
change/only third :fnc [throw]
] [
change/only third :fnc "Soft"
]
return get/any 'fnc-result
]
use [soft-return] [
soft-return: func [[throw] body-result [any-type!]] [
thr: off
return get/any 'body-result
]
do-body: bind/copy body 'soft-return
]
fnc: func modified-spec reduce [
:thr-on
:fnc-return :do-body
]
do-body: does third second :fnc
change skip second :fnc 2 :do-body
:fnc
]
]
with a help of SOFT-FUNC we are now able to write the HARD function or any
other function with similar properties
hard: soft-func [u v] [soft-return u first v]
; Error test:
arg1: func [x] [return make error! x]
arg2: ["some error"]
probe disarm hard :arg1 arg2
make object! [
code: 800
type: 'user
id: 'message
arg1: "some error"
arg2: none
arg3: none
near: [return make error! x]
where: none
]
arg1: func [[throw] x] [return x]
arg2: [1]
test: does [hard :arg1 arg2 2]
test ; == 1
Regards
Ladislav
