Multi-iteration transform
From Friend2Friend Wiki
Multi-iteration transforms are XSL transforms that require more than one iteration of the servicereq processing model to complete, typically used for complex [service]]s (which are best avoided, KISS!).
This is the oldest and most reliable method of carrying out complex computations, since it does not rely on the availability of EXSLT, and it avoids the xsl:document() bug. However, it is also the slowest, and inconvenient since the intermediate template iterations are currently not validated.
