Sub Articulo 124.0

 I have a problem with TeX exceeding its memory capacity (or most
 probably, myself trying to exceed my TeX knowledge). First Let me
 describe the problem, as there might well be different solutions to
 it. I'm trying to write a macro that formats the kind of diagrams that 
 describe the time behaviour of signals in electronic data
 sheets. Given the following input:
 
 \begin{tabular}
       \signal{XSUS\_G}          {-........-----}
       \signal{XPR\_U}           {.-----........}
 \end{tabular}
 
 I'd like to get:
 	__                  __________
 XSUS_G	  \________________/
            __________
 XPR_U   __/          \________________
 
 for drawing I'm using pstricks, but I'm considering switching to
 metapost.