Hi John, On Friday 19 May 2006 19:14, John Coppens wrote: > On Sun, 14 May 2006 14:04:28 +0200 Werner Hoch wrote: > > > > Recursion makes short and powerful programs. > > Yes... But the symbol definition language doesn't have conditional > constructs, does it?
No, but gschem uses recursive functions to draw the symbol. If there are symbols that creates recursion loops, gschem dies. e.g. Symbol A contains symbol A or symbol A contains symbol B symbol B contains symbol A > So how can one get out of a recursion? * count the recursion level. print an error message (and stop) if the recursion is to deep. * check all parent objects before entering next recursion level. > > In future there may be (will be) support for symbol inheritance. > > http://archives.seul.org/geda/dev/Oct-2005/msg00043.html > > Inheritance seems way more logical. Symbols are passive objects... Or > maybe we could even make them active (methods), so we need only one > DIP component, one SIP... Inheritance is intented to create heavy symbols: e.g. the device 2N2222 could contain: a transistor symbol a footprint attribute a spice model attribute a documentation attribute The basic transistor symbol could be reused for many transistor devices. regards Werner
