On 25-11-2022 01:03, Zelphir Kaltstahl wrote:
ice-9/boot-9.scm:1685:16: In procedure raise-exception: ERROR: 1. &contract-violated 2. &message: "contract violated" 3. &origin: bla 4. &irritants: (> foo 10) 5. &irritants: (> 10 10)
I don't understand this -- (> 10 10) is always false, no? I would interpret such an error message as 'you can't call this procedure at all, it requires a contradiction to hold'. What's the purpose of (> 10 10) here? I guess 'foo=10'?
If you want to include the value of 'foo', this can be made more explicit, e.g.:
4. &unsatisfied-constraint: (> foo 10)
5. &argument: foo, 10 (i.e. this &argument condition has two fields)
That would avoid the vague '&irritants' -- I mean,
A base type used for storing information about the causes of
another condition in a compound condition.
is rather vague, it could refer to 'the condition causing this
condition', or the values of the arguments, or some property of those
arguments, or ...
~~~~Nice! Now I have the value of `foo` in this case as well and that could be useful information in cases, when I get a violated contract unexpectedly.However, having irritants twice seems a bit weird. Is this something, that is safe to do? Something expected and probably unchanging in future versions of GNU Guile? Or does it merely work by chance?I could always make another exception type like "exception-with-irritant-values" or something and use that, instead of a second "with irritants" call.
I don't know if having multiple instances of the same condition type inside a single condition is supported.
However, given that &irritants is plural (instead of a singular &irritant), and the documentation also mentions 'causes' (plural!):
A base type used for storing information about the causes of
another condition in a compound condition.
... why not make the value of &irritants a list, e.g.:
> 1. &contract-violated
> 2. &message: "contract violated"
> 3. &origin: bla
> 4. &irritants: ((> foo 10) (> 10 10))
Greetings,
Maxime.
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