Hello all, As many people will know, the LaTeX team have developed an expandable FPU as part of expl3. That gets quite a bit of use, but one area we can't currently address is random numbers. The pgf bundle has a pseudo-random number generator, but that can't be expandable (you need to track the seed). The usefulness of pseudo-random numbers has come up a few times recently, and so we'd like to address this. (Expandable floating point evaluation is pretty handy as an end user!)
Both pdfTeX and LuaTeX include a series of primitives that expose a lower-level pseudo-random number generator (I assume from C: there is very little actual code in the pdfTeX WEB source to implement these). That gives us a way of providing expandable random numbers at the macro level, but at present will be limited to those engines. As this is something of an 'extra' (not core functionality), we will at present accept that it's not doable in XeTeX/e-(u)pTeX (and issue an error if requested), but it would be handy if the functionality could find its way into those engines. For reference, the 'full set' of primitives in this area is - \(pdf)uniformdeviate - \(pdf)normaldeviate - \(pdf)randomseed - \(pdf)setrandomseed (LuaTeX drops the 'pdf' part of the names.) Joseph -------------------------------------------------- Subscriptions, Archive, and List information, etc.: http://tug.org/mailman/listinfo/xetex
