
.ndr Format:
------------

It is the format of graphic files  produced by the nd editor. A net is
described  by a  series  of declarations  of  places, transitions  and
edges, followed by  a net name declaration.  The  net described is the
superposition of these declarations.

.ndr			::= (<trdesc>|<pldesc>)* (<edgedesc>)* <netdesc>
trdesc			::= 't' <xpos> <ypos> <transition> <eft> <lft> <anchor>
			 |  't' <xpos> <ypos> <transition> <anchor> <eft> <lft> <anchor> <label> <anchor>
pldesc 			::= 'p' <xpos> <ypos> <place> <marking> <anchor> {<label> <anchor>}
edgedesc 		::= 'e' <place> <transition> <weight> <anchor>
			 |  'e' <place> <ang> <rad> <transition> <ang> <rad> <weight> <anchor>
			 |  'e' <transition> <place> <normal_weight> <anchor>
			 |  'e' <transition> <ang> <rad> <place> <ang> <rad> <normal_weight> <anchor>
netdesc			::= 'h' <net> {<nodesize> {<bgcolor>}}
eft 			::= {-}INT
lft 	 		::= {-}INT | 'w'
weight			::= normal_weight | test_weight | inhibitor_weight
test_weight		::= '?'normal_weight
inhibitor_weight	::= '?-'normal_weight
normal_weight, marking	::= INT{'K'|'M'}
xpos, ypos, rad		::= FLOAT
ang			::= UFLOAT
net, place, transition, label 	::= ANAME | '{'QNAME'}'
anchor			::= 'n' | 'nw' | 'w' | 'sw' | 's' | 'se' | 'e' | 'ne' | 'c'
FLOAT			::= unsigned float (without exponent)
UFLOAT			::= unsigned float between 0 and 1 (without exponent)
INT			::= unsigned integer
ANAME			::= as for .net
QNAME			::= as for .net
<nodesize>		::= 'small' | 'normal' | 'large'
<bgcolor>		::= any tcl-tk color

Notes:
  Node declarations must precede edge declarations.
  The last declaration must be the netname declaration (h).
  Empty lines and lines beginning with '#'are considered comments.
  A '-' starting an eft or lft denotes an open interval end. 
  In any transition declaration, one must have `lft >= `eft or lft = 'w',
	where `e denotes e if e>=0, or (-e)-1 otherwise
  If eft = lft, then they may not be both negative (intervals may not be empty).
  The letter 'K' (resp. 'M') following a weight or marking multiplies it by 10^3 (resp. 10^6).
