Ok, let's make that a potential optimisation, not a requirement. I'm fine with having the error log extracted immediately after validation and throwing away the result document if the users asked to do so by passing the option. I would guess that the XSLT based validation is already heavy enough anyway.
For lazy error log extraction we need to store the validation report. So maybe we could just compromise: If the user opts for storing the result report error_log will use lazy extraction, if not error log needs to be set inside __call__. Classical trade of memory vs speed :)
After looking at the code I feel this solution's implementation would be quite a bit clumsier compared to now, e.g. because you need to save the file uri/name of the validated tree in the lazy-extraction case for latter reuse when error_log is first accessed. So I don't think it's worth the effort now. Holger -- Jetzt kostenlos herunterladen: Internet Explorer 8 und Mozilla Firefox 3.5 - sicherer, schneller und einfacher! http://portal.gmx.net/de/go/atbrowser