53 lines
1.2 KiB
Text
53 lines
1.2 KiB
Text
|
There are people who consider `abort` to be the most
|
||
|
|
fundamental building block in writing programs. For
|
||
|
|
them, it is not just a debugging tool.
|
||
|
|
|
||
|
|
~~~
|
||
|
|
:s:shout (s-) '!_ s:prepend s:put nl 'Stack_:_ s:put dump-stack nl ;
|
||
|
|
{{
|
||
|
|
'Depth var
|
||
|
|
:message (-) 'abort_with_trail_invoked s:shout nl
|
||
|
|
'Do__reset__to_clear_stack. s:put nl ;
|
||
|
|
:put-name (a-) fetch d:lookup-xt
|
||
|
|
dup n:-zero? [ d:name s:put nl ] [ drop ] choose ;
|
||
|
|
---reveal---
|
||
|
|
:trail repeat pop put-name again ;
|
||
|
|
:abort (-?) depth !Depth message trail ;
|
||
|
|
:s:abort (s-) 's:abort_:_ s:prepend s:put nl abort ;
|
||
|
|
}}
|
||
|
|
~~~
|
||
|
|
|
||
|
|
`trail` leaves garbage on the stack.
|
||
|
|
This garbage is difficult to shake off since `trail`
|
||
|
|
destroys the contents of the return stack. The easiest
|
||
|
|
way I have found so far is to `reset` manually.
|
||
|
|
|
||
|
|
To test, run the following code interactively:
|
||
|
|
|
||
|
|
```
|
||
|
|
:a 'aaa s:abort ;
|
||
|
|
:b a ;
|
||
|
|
:c b ;
|
||
|
|
c
|
||
|
|
reset
|
||
|
|
```
|
||
|
|
|
||
|
|
## assert
|
||
|
|
|
||
|
|
~~~
|
||
|
|
:assert (q-) call [ abort ] -if ;
|
||
|
|
:assert.verbous (q-) call [ 'assert_:_fail s:abort ] -if ;
|
||
|
|
~~~
|
||
|
|
|
||
|
|
If `0;` is invoked with an empty stack, it fails and
|
||
|
|
kills the session.
|
||
|
|
|
||
|
|
```
|
||
|
|
:t 'before_ s:put 0; 'after s:put nl ;
|
||
|
|
'#0_t_nl_#1_t_nl s:evaluate
|
||
|
|
'reset_t s:evaluate (--_kills_session
|
||
|
|
```
|
||
|
|
|
||
|
|
If this is dangerous, place an assertion before `0;` .
|
||
|
|
|