Index: trunk/doc-rnd/ddrc/proposal1.txt
===================================================================
--- trunk/doc-rnd/ddrc/proposal1.txt	(revision 2833)
+++ trunk/doc-rnd/ddrc/proposal1.txt	(revision 2834)
@@ -25,6 +25,7 @@
 P9   - an element primitive (element line, element arc(?), pin, pad, element name)
 P10  - an element as a whole
 P11  - a net
+P61  - a 2D coordinate with or without layer information
 
 P12 Objects have named properties (or fields):
 P13  - core attributes: for each object type a predefined set of key=value
@@ -62,6 +63,7 @@
 P24  - it is an existing object
 P25  - it is a non-empty list
 P26  - it is a non-zero number or non-empty string
+P69  - it is a valid coordinate
 
     An expression is one of:
 
@@ -215,3 +217,19 @@
      - meta-type, or a group:
        - copper: primitive that results in copper (arc, line, polygon, text (on copper), via, pin, pad)
        - drilled: anything that drills the board (via, pin)
+
+P62 gridup(EXPR, NUM1, NUM2)
+    If expression is an object, return a list of coordinates that are on
+    the object, evenly spaced:
+P63  - for lines and arcs, the points are evenly spaced on the centerlane with
+        a gap of NUM1, starting from both endpoints, having the corner case in
+        the middle; if NUM2 is 0, the gap at the middle may be larger than NUM1,
+        else it may be smaller than NUM1.
+P64  - for polygons take a grid of NUM1*NUM2 spacing (NUM1 is always axis
+       aligned to X, NUM2 to Y). The offset of the grid is unspecified
+P65  - element and text are ignored
+P66  - a pad or pin is approximated with a polygon
+P67  - for networks, iterate over all objects and append unique coordinates on
+       the resulting list
+P68 There's no guarantee on the particular order of the list.
+