Added missing files, tests for angle and length (universal DRC), some clarifications and bug fixes.

src/db/db/gsiDeclDbEdges.cc

@@ -581,15 +581,15 @@ Class<db::Edges> decl_Edges (decl_dbShapeCollection, "db", "Edges",
     "horizontal = edges.with_orientation(0, true)\n"
     "@/code\n"
   ) +
-  method_ext ("with_angle", with_angle2, gsi::arg ("min_angle"), gsi::arg ("max_angle"), gsi::arg ("inverse"), gsi::arg ("include_amin", true), gsi::arg ("include_amax", true),
+  method_ext ("with_angle", with_angle2, gsi::arg ("min_angle"), gsi::arg ("max_angle"), gsi::arg ("inverse"), gsi::arg ("include_min_angle", true), gsi::arg ("include_max_angle", false),
     "@brief Filter the edges by orientation\n"
     "Filters the edges in the edge collection by orientation. If \"inverse\" is false, only "
-    "edges which have an angle to the x-axis larger or equal to \"min_angle\" and less than \"max_angle\" are "
+    "edges which have an angle to the x-axis larger or equal to \"min_angle\" (depending on \"include_min_angle\") and equal or less than \"max_angle\" (depending on \"include_max_angle\") are "
     "returned. If \"inverse\" is true, "
     "edges which do not conform to this criterion are returned.\n"
     "\n"
-    "With \"include_min\" set to true (the default), the minimum angle is included in the criterion while with false, the "
+    "With \"include_min_angle\" set to true (the default), the minimum angle is included in the criterion while with false, the "
-    "minimum angle itself is not included. Same for \"include_max\".\n"
+    "minimum angle itself is not included. Same for \"include_max_angle\" where the default is false, meaning the maximum angle is not included in the range.\n"
     "\n"
     "The two \"include..\" arguments have been added in version 0.27."
   ) +

src/db/unit_tests/dbEdgesTests.cc

@@ -200,23 +200,35 @@ TEST(4)
     EXPECT_EQ (r.filtered (f1).to_string (), "(0,200;100,200);(100,0;0,0);(300,0;200,0)");
   }
   {
-    db::EdgeOrientationFilter f1 (50.0, true, 80.0, true, false);
+    db::EdgeOrientationFilter f1 (50.0, true, 80.0, false, false);
     EXPECT_EQ (r.filtered (f1).to_string (), "(200,0;250,200);(250,-200;300,0)");
   }
   {
-    db::EdgeOrientationFilter f1 (50.0, true, 80.0, true, true);
+    db::EdgeOrientationFilter f1 (50.0, true, 80.0, false, true);
     EXPECT_EQ (r.filtered (f1).to_string (), "(0,0;0,200);(0,200;100,200);(100,200;100,0);(100,0;0,0);(250,200;300,0);(300,0;200,0);(200,0;250,-200)");
   }
+  {
+    db::EdgeOrientationFilter f1 (0.0, true, 1.0, false, false);
+    EXPECT_EQ (r.filtered (f1).to_string (), "(0,200;100,200);(100,0;0,0);(300,0;200,0)");
+  }
+  {
+    db::EdgeOrientationFilter f1 (-1.0, true, 1.0, false, false);
+    EXPECT_EQ (r.filtered (f1).to_string (), "(0,200;100,200);(100,0;0,0);(300,0;200,0)");
+  }
+  {
+    db::EdgeOrientationFilter f1 (-1.0, true, 0.0, false, false);
+    EXPECT_EQ (r.filtered (f1).to_string (), "");
+  }
+  {
+    db::EdgeOrientationFilter f1 (-1.0, true, 0.0, true, false);
+    EXPECT_EQ (r.filtered (f1).to_string (), "(0,200;100,200);(100,0;0,0);(300,0;200,0)");
+  }
   {
     db::EdgeOrientationFilter f1 (0.0, true, 1.0, true, false);
     EXPECT_EQ (r.filtered (f1).to_string (), "(0,200;100,200);(100,0;0,0);(300,0;200,0)");
   }
   {
-    db::EdgeOrientationFilter f1 (-1.0, true, 1.0, true, false);
+    db::EdgeOrientationFilter f1 (0.0, false, 1.0, true, false);
-    EXPECT_EQ (r.filtered (f1).to_string (), "(0,200;100,200);(100,0;0,0);(300,0;200,0)");
-  }
-  {
-    db::EdgeOrientationFilter f1 (-1.0, true, 0.0, true, false);
     EXPECT_EQ (r.filtered (f1).to_string (), "");
   }
   {
@@ -224,15 +236,15 @@ TEST(4)
     EXPECT_EQ (r.filtered (f1).to_string (), "(0,0;0,200);(100,200;100,0)");
   }
   {
-    db::EdgeOrientationFilter f1 (90.0, true, 91.0, true, false);
+    db::EdgeOrientationFilter f1 (90.0, true, 91.0, false, false);
     EXPECT_EQ (r.filtered (f1).to_string (), "(0,0;0,200);(100,200;100,0)");
   }
   {
-    db::EdgeOrientationFilter f1 (89.0, true, 91.0, true, false);
+    db::EdgeOrientationFilter f1 (89.0, true, 91.0, false, false);
     EXPECT_EQ (r.filtered (f1).to_string (), "(0,0;0,200);(100,200;100,0)");
   }
   {
-    db::EdgeOrientationFilter f1 (89.0, true, 90.0, true, false);
+    db::EdgeOrientationFilter f1 (89.0, true, 90.0, false, false);
     EXPECT_EQ (r.filtered (f1).to_string (), "");
   }
 }

src/lay/lay/doc/about/drc_ref_expressions.xml

@@ -0,0 +1,664 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE language SYSTEM "klayout_doc.dtd">
+
+<!-- generated by /home/matthias/klayout/master/scripts/extract_doc.rb  -->
+<!-- DO NOT EDIT! -->
+
+<doc>
+<title>DRC Reference: DRC expressions</title>
+<keyword name="Expressions"/>
+<p>
+DRC expression objects represent abstract recipes for the <a href="/about/drc_ref_layer.xml#drc">Layer#drc</a> universal DRC function.
+For example, when using a universal DRC expression like this:
+</p><p>
+<pre>
+out = in.drc(width &lt; 2.0)
+</pre>
+</p><p>
+"width &lt; 2.0" forms a DRC expression object. DRC expression objects have methods which
+manipulate or evaluate the results of this expression. In addition, DRC expressions have a
+result type, which is either polygon, edge or edge pair. The result type is defined by the
+expression generating it. In the example above, "width &lt; 2.0" is a DRC width check which
+renders edge pairs. To obtain polygons from these edge pairs, use the "polygons" method:
+</p><p>
+<pre>
+out = in.drc((width &lt; 2.0).polygons)
+</pre>
+</p><p>
+The following documentation will list the methods available for DRC expression objects.
+</p>
+<h2-index/>
+<a name="!"/><h2>"!" - Logical not</h2>
+<keyword name="!"/>
+<p>Usage:</p>
+<ul>
+<li><tt>! expression</tt></li>
+</ul>
+<p>
+This operator will evaluate the expression after. If this expression renders
+an empty result, the operator will return the primary shape. Otherwise it will
+return an empty result.
+</p><p>
+This operator can be used together with predicates such a "rectangles" to 
+invert their meaning. For example, this code selects all primary shapes which
+are not rectangles:
+</p><p>
+<pre>
+out = in.drc(! rectangles)
+out = in.drc(! primary.rectangles)   # equivalent
+</pre>
+</p>
+<a name="&amp;"/><h2>"&amp;" - Boolean AND between the results of two expressions</h2>
+<keyword name="&amp;"/>
+<p>Usage:</p>
+<ul>
+<li><tt>expression &amp; expression</tt></li>
+</ul>
+<p>
+The &amp; operator will compute the boolean AND between the results
+of two expressions. The expression types need to be edge or polygon.
+</p><p>
+The following example computes the partial edges where width is less than 
+0.3 micrometers and space is less than 0.2 micrometers:
+</p><p>
+<pre>
+out = in.drc((width &lt; 0.3).edges &amp; (space &lt; 0.2).edges)
+</pre>
+</p>
+<a name="+"/><h2>"+" - Boolean OR between the results of two expressions</h2>
+<keyword name="+"/>
+<p>Usage:</p>
+<ul>
+<li><tt>expression + expression</tt></li>
+</ul>
+<p>
+The + operator will join the results of two expressions.
+</p>
+<a name="-"/><h2>"-" - Boolean NOT between the results of two expressions</h2>
+<keyword name="-"/>
+<p>Usage:</p>
+<ul>
+<li><tt>expression - expression</tt></li>
+</ul>
+<p>
+The - operator will compute the difference between the results
+of two expressions. The NOT operation is defined for polygons,
+edges and polygons subtracted from edges (first argument edge,
+second argument polygon).
+</p><p>
+The following example will produce edge markers where the 
+width of is less then 0.3 micron but not inside polygons on 
+the "waive" layer:
+</p><p>
+<pre>
+out = in.drc((width &lt; 0.3).edges - secondary(waive))
+</pre>
+</p>
+<a name="^"/><h2>"^" - Boolean XOR between the results of two expressions</h2>
+<keyword name="^"/>
+<p>Usage:</p>
+<ul>
+<li><tt>expression - expression</tt></li>
+</ul>
+<p>
+The ^ operator will compute the XOR (symmetric difference) between the results
+of two expressions. The XOR operation is defined for polygons and edges.
+Both expressions must be of the same type.
+</p>
+<a name="angle"/><h2>"angle" - Selects edges based on their angle</h2>
+<keyword name="angle"/>
+<p>Usage:</p>
+<ul>
+<li><tt>expression.angle (in condition)</tt></li>
+</ul>
+<p>
+This operation selects edges by their angle, measured against the horizontal 
+axis in the mathematical sense. 
+</p><p>
+For this measurement edges are considered without their direction and straight lines. 
+A horizontal edge has an angle of zero degree. A vertical one has
+an angle of 90 degee. The angle range is from -90 (exclusive) to 90 degree (inclusive).
+</p><p>
+If the input shapes are not polygons or edge pairs, they are converted to edges 
+before the angle test is made.
+</p><p>
+For example, the following code selects all edges from the primary shape which are 45 degree
+(up) or 135 degree (down). The "+" will join the results:
+</p><p>
+<pre>
+out = in.drc((angle == 45) + (angle == 135)) 
+out = in.drc((primary.angle == 45) + (primary.angle == 135))    # equivalent
+</pre>
+</p><p>
+Note that angle checks usually imply the need to rotation variant formation as cells which
+are placed unrotated and rotated by 90 degree cannot be considered identical. This imposes
+a performance penalty in hierarchical mode. If possible, consider using <a href="/about/drc_ref_drc.xml#rectilinear">DRC#rectilinear</a> for
+example to detect shapes with non-manhattan geometry instead of using angle checks.
+</p><p>
+The "angle" method is available as a plain function or as a method on <a href="#DRC">DRC</a> expressions.
+The plain function is equivalent to "primary.angle".
+</p>
+<a name="area"/><h2>"area" - Selects the primary shape if the area is meeting the condition</h2>
+<keyword name="area"/>
+<p>Usage:</p>
+<ul>
+<li><tt>expression.area (in condition)</tt></li>
+</ul>
+<p>
+This operation is used in conditions to select shapes based on their area.
+It is applicable on polygon expressions. The result will be the input 
+polygons if the area condition is met. 
+</p><p>
+See <a href="#drc">drc</a> for more details about comparison specs.
+</p><p>
+The following example will select all polygons with an area less than 2.0 square micrometers:
+</p><p>
+<pre>
+out = in.drc(area &lt; 2.0)
+out = in.drc(primary.area &lt; 2.0)   # equivalent
+</pre>
+</p><p>
+The area method is available as a plain function or as a method on <a href="#DRC">DRC</a> expressions.
+The plain function is equivalent to "primary.area".
+</p>
+<a name="bbox_height"/><h2>"bbox_height" - Selects the primary shape if its bounding box height is meeting the condition</h2>
+<keyword name="bbox_height"/>
+<p>Usage:</p>
+<ul>
+<li><tt>expression.bbox_height (in condition)</tt></li>
+</ul>
+<p>
+This operation acts similar to <a href="/about/drc_ref_drc.xml#bbox_min">DRC#bbox_min</a>, but takes the height of the shape's 
+bounding box. In general, it's more advisable to use <a href="/about/drc_ref_drc.xml#bbox_min">DRC#bbox_min</a> or <a href="/about/drc_ref_drc.xml#bbox_max">DRC#bbox_max</a>
+because bbox_height implies a certain orientation. This can imply variant formation in 
+hierarchical contexts: cells rotated by 90 degree have to be treated differently from
+ones not rotated. This usually results in a larger computation effort and larger result files.
+</p><p>
+The "bbox_height" method is available as a plain function or as a method on <a href="#DRC">DRC</a> expressions.
+The plain function is equivalent to "primary.bbox_height".
+</p>
+<a name="bbox_max"/><h2>"bbox_max" - Selects the primary shape if its bounding box larger dimension is meeting the condition</h2>
+<keyword name="bbox_max"/>
+<p>Usage:</p>
+<ul>
+<li><tt>expression.bbox_max (in condition)</tt></li>
+</ul>
+<p>
+This operation acts similar to <a href="/about/drc_ref_drc.xml#bbox_min">DRC#bbox_min</a>, but takes the larger dimension of the shape's 
+bounding box.
+</p><p>
+The "bbox_max" method is available as a plain function or as a method on <a href="#DRC">DRC</a> expressions.
+The plain function is equivalent to "primary.bbox_max".
+</p>
+<a name="bbox_min"/><h2>"bbox_min" - Selects the primary shape if its bounding box smaller dimension is meeting the condition</h2>
+<keyword name="bbox_min"/>
+<p>Usage:</p>
+<ul>
+<li><tt>expression.bbox_min (in condition)</tt></li>
+</ul>
+<p>
+This operation is used in conditions to select shapes based on smaller dimension of their bounding boxes.
+It is applicable on polygon expressions. The result will be the input 
+polygons if the bounding box condition is met. 
+</p><p>
+See <a href="#drc">drc</a> for more details about comparison specs.
+</p><p>
+The following example will select all polygons whose bounding box smaller dimension is larger
+than 200 nm:
+</p><p>
+<pre>
+out = in.drc(bbox_min &gt; 200.nm)
+out = in.drc(primary.bbox_min &gt; 200.nm)   # equivalent
+</pre>
+</p><p>
+The "bbox_min" method is available as a plain function or as a method on <a href="#DRC">DRC</a> expressions.
+The plain function is equivalent to "primary.bbox_min".
+</p>
+<a name="bbox_width"/><h2>"bbox_width" - Selects the primary shape if its bounding box width is meeting the condition</h2>
+<keyword name="bbox_width"/>
+<p>Usage:</p>
+<ul>
+<li><tt>expression.bbox_width (in condition)</tt></li>
+</ul>
+<p>
+This operation acts similar to <a href="/about/drc_ref_drc.xml#bbox_min">DRC#bbox_min</a>, but takes the width of the shape's 
+bounding box. In general, it's more advisable to use <a href="/about/drc_ref_drc.xml#bbox_min">DRC#bbox_min</a> or <a href="/about/drc_ref_drc.xml#bbox_max">DRC#bbox_max</a>
+because bbox_width implies a certain orientation. This can imply variant formation in 
+hierarchical contexts: cells rotated by 90 degree have to be treated differently from
+ones not rotated. This usually results in a larger computation effort and larger result files.
+</p><p>
+The "bbox_width" method is available as a plain function or as a method on <a href="#DRC">DRC</a> expressions.
+The plain function is equivalent to "primary.bbox_width".
+</p>
+<a name="centers"/><h2>"centers" - Returns the part at the center of each edge of the input</h2>
+<keyword name="centers"/>
+<p>Usage:</p>
+<ul>
+<li><tt>expression.centers(length)</tt></li>
+<li><tt>expression.end_segments(length, fraction)</tt></li>
+</ul>
+<p>
+This method acts on edge expressions and delivers a specific part of each edge.
+See <a href="/about/drc_ref_layer.xml#centers">layer#centers</a> for details about this functionality.
+</p>
+<a name="corners (in condition)"/><h2>"corners (in condition)" - Applies smoothing</h2>
+<keyword name="corners (in condition)"/>
+<p>Usage:</p>
+<ul>
+<li><tt>expression.corners</tt></li>
+<li><tt>expression.corners(as_dots)</tt></li>
+<li><tt>expression.corners(as_boxes)</tt></li>
+</ul>
+<p>
+This operation acts on polygons and selects the corners of the polygons.
+It can be put into a condition to select corners by their angles. The angle of
+a corner is positive for a turn to the left if walking a polygon counterclockwise
+and negative for the turn to the right. Angles take values between -180 and 180 degree.
+</p><p>
+When using "as_dots" for the argument, the operation will return single-point edges at
+the selected corners. With "as_boxes" (the default), small (2x2 DBU) rectangles will be
+produced at each selected corner.
+</p><p>
+The following example selects all corners:
+</p><p>
+<pre>
+out = in.drc(corners)
+out = in.drc(primary.corners)    # equivalent
+</pre>
+</p><p>
+The following example selects all inner corners:
+</p><p>
+<pre>
+out = in.drc(corners &lt; 0)
+out = in.drc(primary.corners &lt; 0)    # equivalent
+</pre>
+</p><p>
+The "corners" method is available as a plain function or as a method on <a href="#DRC">DRC</a> expressions.
+The plain function is equivalent to "primary.corners".
+</p>
+<a name="count"/><h2>"count" - Selects a expression result based on the number of (local) shapes</h2>
+<keyword name="count"/>
+<p>Usage:</p>
+<ul>
+<li><tt>expression.count (in condition)</tt></li>
+</ul>
+<p>
+This operation is used in conditions to select expression results based on their
+count. "count" is used as a method on a expression. It will evaluate the expression locally
+and return the original result if the shape count in the result is matching the condition.
+</p><p>
+See <a href="#drc">drc</a> for more details about comparison specs.
+</p><p>
+Note that the expression is evaluated locally: for each primary shape, the expression is
+evaluated and the count of the resulting edge, edge pair or polygon set is taken.
+As the primary input will always have a single item (the local shape), using "count" on
+primary does not really make sense. It can be used on derived expressions however.
+</p><p>
+The following example selects triangles:
+</p><p>
+<pre>
+out = in.drc(if_any(corners.count == 3))
+</pre>
+</p><p>
+Note "if_any" which selects the primary shape if the argument evaluates to a non-empty
+result. Without "if_any" three corners are returned for each triangle.
+</p>
+<a name="edges"/><h2>"edges" - Converts the input shapes into edges</h2>
+<keyword name="edges"/>
+<p>Usage:</p>
+<ul>
+<li><tt>expression.edges</tt></li>
+</ul>
+<p>
+Polygons will be separated into edges forming their contours. Edge pairs will be 
+decomposed into individual edges.
+</p><p>
+Contrary most other operations, "edges" does not have a plain function equivalent
+as this is reserved for the function generating an edges layer.
+To generate the edges of the primary shapes, use "primary" explicit as the source
+for the edges:
+</p><p>
+<pre>
+out = in.drc(primary.edges)
+</pre>
+</p>
+<a name="end_segments"/><h2>"end_segments" - Returns the part at the end of each edge of the input</h2>
+<keyword name="end_segments"/>
+<p>Usage:</p>
+<ul>
+<li><tt>expression.end_segments(length)</tt></li>
+<li><tt>expression.end_segments(length, fraction)</tt></li>
+</ul>
+<p>
+This method acts on edge expressions and delivers a specific part of each edge.
+See <a href="/about/drc_ref_layer.xml#end_segments">layer#end_segments</a> for details about this functionality.
+</p>
+<a name="extended"/><h2>"extended" - Returns polygons describing an area along the edges of the input</h2>
+<keyword name="extended"/>
+<p>Usage:</p>
+<ul>
+<li><tt>expression.extended([:begin =&gt; b,] [:end =&gt; e,] [:out =&gt; o,] [:in =&gt; i], [:joined =&gt; true])</tt></li>
+<li><tt>expression.extended(b, e, o, i)</tt></li>
+</ul>
+<p>
+This method acts on edge expressions.
+It will create a polygon for each edge
+tracing the edge with certain offsets to the edge. "o" is the offset applied to the 
+outer side of the edge, "i" is the offset applied to the inner side of the edge.
+"b" is the offset applied at the beginning and "e" is the offset applied at the end.
+</p>
+<a name="extended_in"/><h2>"extended_in" - Returns polygons describing an area along the edges of the input</h2>
+<keyword name="extended_in"/>
+<p>Usage:</p>
+<ul>
+<li><tt>expression.extended_in(d)</tt></li>
+</ul>
+<p>
+This method acts on edge expressions. Polygons are generated for 
+each edge describing the edge drawn with a certain width extending into
+the "inside" (the right side when looking from start to end).
+This method is basically equivalent to the <a href="#extended">extended</a> method:
+"extended(0, 0, 0, dist)".
+A version extending to the outside is <a href="#extended_out">extended_out</a>.
+</p>
+<a name="extended_out"/><h2>"extended_out" - Returns polygons describing an area along the edges of the input</h2>
+<keyword name="extended_out"/>
+<p>Usage:</p>
+<ul>
+<li><tt>expression.extended_out(d)</tt></li>
+</ul>
+<p>
+This method acts on edge expressions. Polygons are generated for 
+each edge describing the edge drawn with a certain width extending into
+the "outside" (the left side when looking from start to end).
+This method is basically equivalent to the <a href="#extended">extended</a> method:
+"extended(0, 0, dist, 0)".
+A version extending to the inside is <a href="#extended_in">extended_in</a>.
+</p>
+<a name="extent_refs"/><h2>"extent_refs" - Returns partial references to the boundings boxes of the polygons</h2>
+<keyword name="extent_refs"/>
+<p>Usage:</p>
+<ul>
+<li><tt>expression.extent_refs([ options ])</tt></li>
+</ul>
+<p>
+The extent_refs operation acts on polygons and has the same effect than <a href="/about/drc_ref_layer.xml#extent_refs">Layer#extent_refs</a>.
+It takes the same arguments. It is available as a method on <a href="#DRC">DRC</a> expressions or
+as plain function, in which case it acts on the primary shapes.
+</p>
+<a name="extents"/><h2>"extents" - Returns the bounding box of each input object</h2>
+<keyword name="extents"/>
+<p>Usage:</p>
+<ul>
+<li><tt>expression.extents([ enlargement ])</tt></li>
+</ul>
+<p>
+This method provides the same functionality as <a href="/about/drc_ref_layer.xml#extents">Layer#extents</a> and takes the same
+arguments. It returns the bounding boxes of the input objects. It acts on edge
+edge pair and polygon expressions.
+</p><p>
+The "extents" method is available as a plain function or as a method on <a href="#DRC">DRC</a> expressions.
+The plain function is equivalent to "primary.extents".
+</p>
+<a name="first_edges"/><h2>"first_edges" - Returns the first edges of edge pairs</h2>
+<keyword name="first_edges"/>
+<p>Usage:</p>
+<ul>
+<li><tt>expression.extents([ enlargement ])</tt></li>
+</ul>
+<p>
+This method acts on edge pair expressions and returns the first edges of the
+edge pairs delivered by the expression.
+</p>
+<a name="holes"/><h2>"holes" - Selects all holes from the input polygons</h2>
+<keyword name="holes"/>
+<p>Usage:</p>
+<ul>
+<li><tt>expression.holes</tt></li>
+</ul>
+<p>
+This operation can be used as a plain function in which case it acts on primary
+shapes or can be used as method on another DRC expression.
+The following example selects all holes with an area larger than 2 square micrometers:
+</p><p>
+<pre>
+out = in.drc(holes.area &gt; 2.um)
+out = in.drc(primary.holes.area &gt; 2.um)   # equivalent
+</pre>
+</p>
+<a name="hulls"/><h2>"hulls" - Selects all hulls from the input polygons</h2>
+<keyword name="hulls"/>
+<p>Usage:</p>
+<ul>
+<li><tt>expression.hulls</tt></li>
+</ul>
+<p>
+The hulls are the outer contours of the input polygons. By selecting hulls only,
+all holes will be closed.
+</p><p>
+This operation can be used as a plain function in which case it acts on primary
+shapes or can be used as method on another DRC expression.
+The following example closes all holes:
+</p><p>
+<pre>
+out = in.drc(hulls)
+out = in.drc(primary.hulls)   # equivalent
+</pre>
+</p>
+<a name="length"/><h2>"length" - Selects edges based on their length</h2>
+<keyword name="length"/>
+<p>Usage:</p>
+<ul>
+<li><tt>expression.length (in condition)</tt></li>
+</ul>
+<p>
+This operation will select those edges which are meeting the length
+criterion. Non-edge shapes (polygons, edge pairs) will be converted to edges before.
+</p><p>
+For example, this code selects all edges from the primary shape which are longer or
+equal than 1 micrometer:
+</p><p>
+<pre>
+out = in.drc(length &gt;= 1.um) 
+out = in.drc(primary.length &gt;= 1.um)   # equivalent
+</pre>
+</p><p>
+The "length" method is available as a plain function or as a method on <a href="#DRC">DRC</a> expressions.
+The plain function is equivalent to "primary.length".
+</p>
+<a name="merged"/><h2>"merged" - Returns the merged input polygons, optionally selecting multi-overlap</h2>
+<keyword name="merged"/>
+<p>Usage:</p>
+<ul>
+<li><tt>expression.merged</tt></li>
+<li><tt>expression.merged(min_count)</tt></li>
+</ul>
+<p>
+This operation will act on polygons. Without a min_count argument, the merged
+polygons will be returned.
+</p><p>
+With a min_count argument, the result will include only those parts where more
+than the given number of polygons overlap. As the primary input is merged already,
+it will always contribute as one.
+</p><p>
+The "merged" method is available as a plain function or as a method on <a href="#DRC">DRC</a> expressions.
+The plain function is equivalent to "primary.merged".
+</p>
+<a name="middle"/><h2>"middle" - Returns the centers of polygon bounding boxes</h2>
+<keyword name="middle"/>
+<p>Usage:</p>
+<ul>
+<li><tt>expression.middle([ options ])</tt></li>
+</ul>
+<p>
+The middle operation acts on polygons and has the same effect than <a href="/about/drc_ref_layer.xml#middle">Layer#middle</a>.
+It takes the same arguments. It is available as a method on <a href="#DRC">DRC</a> expressions or
+as plain function, in which case it acts on the primary shapes.
+</p>
+<a name="odd_polygons"/><h2>"odd_polygons" - Selects all polygons which are non-orientable</h2>
+<keyword name="odd_polygons"/>
+<p>Usage:</p>
+<ul>
+<li><tt>expression.odd_polygons</tt></li>
+</ul>
+<p>
+Non-orientable polygons are for example "8"-shape polygons. Such polygons are
+usually considered harmful as their definition of covered area is depending on the
+wrap count rule in place.
+</p><p>
+This operation can be used as a plain function in which case it acts on primary
+shapes or can be used as method on another DRC expression.
+</p>
+<a name="perimeter"/><h2>"perimeter" - Selects the primary shape if the perimeter is meeting the condition</h2>
+<keyword name="perimeter"/>
+<p>Usage:</p>
+<ul>
+<li><tt>expression.perimeter (in condition)</tt></li>
+</ul>
+<p>
+This operation is used in conditions to select shapes based on their perimeter.
+It is applicable on polygon expressions. The result will be the input 
+polygons if the perimeter condition is met. 
+</p><p>
+See <a href="#drc">drc</a> for more details about comparison specs.
+</p><p>
+The following example will select all polygons with a perimeter less than 10 micrometers:
+</p><p>
+<pre>
+out = in.drc(perimeter &lt; 10.0)
+out = in.drc(primary.perimeter &lt; 10.0)   # equivalent
+</pre>
+</p><p>
+The perimeter method is available as a plain function or as a method on <a href="#DRC">DRC</a> expressions.
+The plain function is equivalent to "primary.perimeter".
+</p>
+<a name="polygons"/><h2>"polygons" - Converts the input shapes into polygons</h2>
+<keyword name="polygons"/>
+<p>Usage:</p>
+<ul>
+<li><tt>expression.polygons([ enlargement ])</tt></li>
+</ul>
+<p>
+Generates polygons from the input shapes. Polygons stay polygons. Edges and edge pairs
+are converted to polygons. For this, the enlargement parameter will specify the 
+edge thickness or augmentation applied to edge pairs. With the default enlargement
+of zero edges will not be converted to valid polygons and degenerated edge pairs
+will not become valid polygons as well.
+</p><p>
+Contrary most other operations, "polygons" does not have a plain function equivalent
+as this is reserved for the function generating a polygon layer.
+</p><p>
+This method is useful for generating polygons from DRC violation markers as shown in
+the following example:
+</p><p>
+<pre>
+out = in.drc((width &lt; 0.5.um).polygons)
+</pre>
+</p>
+<a name="rectangles"/><h2>"rectangles" - Selects all polygons which are rectangles</h2>
+<keyword name="rectangles"/>
+<p>Usage:</p>
+<ul>
+<li><tt>expression.rectangles</tt></li>
+</ul>
+<p>
+This operation can be used as a plain function in which case it acts on primary
+shapes or can be used as method on another DRC expression.
+The following example selects all rectangles:
+</p><p>
+<pre>
+out = in.drc(rectangles)
+out = in.drc(primary.rectangles)    # equivalent
+</pre>
+</p>
+<a name="rectilinear"/><h2>"rectilinear" - Selects all polygons which are rectilinear</h2>
+<keyword name="rectilinear"/>
+<p>Usage:</p>
+<ul>
+<li><tt>expression.rectilinear</tt></li>
+</ul>
+<p>
+Rectilinear polygons only have vertical and horizontal edges. Such polygons are also
+called manhattan polygons.
+</p><p>
+This operation can be used as a plain function in which case it acts on primary
+shapes or can be used as method on another DRC expression.
+The following example selects all manhattan polygons:
+</p><p>
+<pre>
+out = in.drc(rectilinear)
+out = in.drc(primary.rectilinear)    # equivalent
+</pre>
+</p>
+<a name="rounded_corners"/><h2>"rounded_corners" - Applies corner rounding</h2>
+<keyword name="rounded_corners"/>
+<p>Usage:</p>
+<ul>
+<li><tt>expression.rounded_corners(inner, outer, n)</tt></li>
+</ul>
+<p>
+This operation acts on polygons and applies corner rounding the the given inner
+and outer corner radius and the number of points n per full circle. See <a href="/about/drc_ref_layer.xml#rounded_corners">Layer#rounded_corners</a> for more details.
+</p><p>
+The "rounded_corners" method is available as a plain function or as a method on <a href="#DRC">DRC</a> expressions.
+The plain function is equivalent to "primary.rounded_corners".
+</p>
+<a name="second_edges"/><h2>"second_edges" - Returns the second edges of edge pairs</h2>
+<keyword name="second_edges"/>
+<p>Usage:</p>
+<ul>
+<li><tt>expression.extents([ enlargement ])</tt></li>
+</ul>
+<p>
+This method acts on edge pair expressions and returns the second edges of the
+edge pairs delivered by the expression.
+</p>
+<a name="sized"/><h2>"sized" - Returns the sized version of the input</h2>
+<keyword name="sized"/>
+<p>Usage:</p>
+<ul>
+<li><tt>expression.sized(d [, mode])</tt></li>
+<li><tt>expression.sized(dx, dy [, mode]))</tt></li>
+</ul>
+<p>
+This method provides the same functionality as <a href="/about/drc_ref_layer.xml#sized">Layer#sized</a> and takes the same
+arguments. It acts on polygon expressions.
+</p><p>
+The "sized" method is available as a plain function or as a method on <a href="#DRC">DRC</a> expressions.
+The plain function is equivalent to "primary.sized".
+</p>
+<a name="smoothed"/><h2>"smoothed" - Applies smoothing</h2>
+<keyword name="smoothed"/>
+<p>Usage:</p>
+<ul>
+<li><tt>expression.smoothed(d)</tt></li>
+</ul>
+<p>
+This operation acts on polygons and applies polygon smoothing with the tolerance d. See <a href="/about/drc_ref_layer.xml#smoothed">Layer#smoothed</a> for more details.
+</p><p>
+The "smoothed" method is available as a plain function or as a method on <a href="#DRC">DRC</a> expressions.
+The plain function is equivalent to "primary.smoothed".
+</p>
+<a name="start_segments"/><h2>"start_segments" - Returns the part at the beginning of each edge of the input</h2>
+<keyword name="start_segments"/>
+<p>Usage:</p>
+<ul>
+<li><tt>expression.start_segments(length)</tt></li>
+<li><tt>expression.start_segments(length, fraction)</tt></li>
+</ul>
+<p>
+This method acts on edge expressions and delivers a specific part of each edge.
+See <a href="/about/drc_ref_layer.xml#start_segments">layer#start_segments</a> for details about this functionality.
+</p>
+<a name="|"/><h2>"|" - Boolean OR between the results of two expressions</h2>
+<keyword name="|"/>
+<p>Usage:</p>
+<ul>
+<li><tt>expression | expression</tt></li>
+</ul>
+<p>
+The | operator will compute the boolean OR between the results of 
+two expressions. '+' is basically a synonym. Both expressions
+must render the same type.
+</p>
+</doc>

testdata/drc/drcGenericTests_12.drc

@@ -0,0 +1,30 @@
+
+source $drc_test_source
+target $drc_test_target
+
+if $drc_test_deep
+  deep
+  threads(0) # easier to debug
+end
+
+l1 = input(1, 0)
+l2 = input(2, 0)
+l3 = input(3, 0)
+
+l1.output(1, 0)
+l2.output(2, 0)
+l3.output(3, 0)
+
+# edge predicates
+
+l1.drc(length > 5.0).output(100, 0)
+l1.drc(2.0 < length <= 5.0).output(101, 0)
+l1.drc(length <= 2.0).output(102, 0)
+l1.drc(length == 2.0).output(103, 0)
+
+l1.drc(angle == 0.0).output(110, 0)
+l1.drc(angle < 0.0).output(111, 0)
+l1.drc(angle > 0.0).output(112, 0)
+l1.drc(angle == 90).output(113, 0)
+l1.drc((angle == 0.0) + (angle == 90)).output(114, 0)
+