From fafcfd487e02037944dde80d8cdcac8aee028f31 Mon Sep 17 00:00:00 2001
From: Ulf GRIESMANN <ulfgri@gmail.com>
Date: Sat, 5 Nov 2016 11:58:04 -0400
Subject: [PATCH] improved indexing

---
 Basic/@gds_element/private/get_element_data.c |  6 ++--
 Basic/@gds_library/subsref.m                  | 35 ++++++++++++++++--
 Basic/@gds_structure/subsref.m                | 36 +++++++++++++++++--
 Basic/gdsii_version.m                         |  2 +-
 ChangeLog                                     |  9 +++++
 5 files changed, 80 insertions(+), 8 deletions(-)

diff --git a/Basic/@gds_element/private/get_element_data.c b/Basic/@gds_element/private/get_element_data.c
index 54f79d2..ee8c6e4 100644
--- a/Basic/@gds_element/private/get_element_data.c
+++ b/Basic/@gds_element/private/get_element_data.c
@@ -129,7 +129,7 @@ static mxArray*
 get_layer(element_t *pe)
 {
    if (pe->kind == GDS_SREF || pe->kind == GDS_AREF)
-      mexErrMsgTxt("get_element_data :  element as no layer property");
+      return empty_matrix();
    else
       return mxCreateDoubleScalar((double)pe->layer);
 
@@ -143,7 +143,7 @@ static mxArray*
 get_dtype(element_t *pe)
 {
    if (pe->kind == GDS_SREF || pe->kind == GDS_AREF)
-      mexErrMsgTxt("get_element_data :  element as no [data|text|box|node] type property");
+      return empty_matrix();
    else
       return mxCreateDoubleScalar((double)pe->dtype);
 
@@ -266,7 +266,7 @@ get_sname(element_t *pe)
    if (pe->kind == GDS_SREF || pe->kind == GDS_AREF)
       return mxCreateString(pe->sname);
    else
-      mexErrMsgTxt("get_element_data :  element as no sname property");
+      return empty_matrix();
 
    return NULL; /* make compiler happy */
 }
diff --git a/Basic/@gds_library/subsref.m b/Basic/@gds_library/subsref.m
index db8c511..849c7ae 100644
--- a/Basic/@gds_library/subsref.m
+++ b/Basic/@gds_library/subsref.m
@@ -10,11 +10,16 @@
 
 % Ulf Griesmann, NIST, June 2011
 
-    switch ins.type
+    % convert cs-lists --> cell arrays
+    itype = {ins.type};
+    isubs = flatten({ins.subs});
+    
+    % first indexing operator
+    switch itype{1}
  
       case '()'
         
-        idx = ins.subs{:};
+        idx = isubs{1};
         
         if ischar(idx) && idx == ':'
             gstrs = glib.st(1:end);
@@ -39,5 +44,31 @@
         error('gds_library.subsref :  invalid indexing type.');
         
     end
+
+    % pass additional structure indexing to structure subsref method
+    if length(itype) > 1
+        sins.type = itype{2};
+        sins.subs = isubs{2};
+        if iscell(gstrs)
+            gstrs = cellfun(@(x)subsref(x, sins), gstrs, 'Un',0); 
+        else
+            gstrs = subsref(gstrs, sins); 
+        end
+    end
+    
+    % flatten a cell array
+    function fca = flatten(ca)
+        
+        fca = cell(size(ca));
+    
+        for k = 1:length(ca)
+            if iscell(ca{k})
+                ct = ca{k};
+                fca{k} = ct{1};
+            else
+                fca(k) = ca(k);
+            end
+        end    
+    end
   
 end  
diff --git a/Basic/@gds_structure/subsref.m b/Basic/@gds_structure/subsref.m
index 8e79746..b047d1f 100644
--- a/Basic/@gds_structure/subsref.m
+++ b/Basic/@gds_structure/subsref.m
@@ -12,11 +12,17 @@
 
 % Ulf Griesmann, NIST, June 2011
 
-    switch ins.type
+    % convert cs-lists --> cell arrays
+    itype = {ins.type};
+    isubs = flatten({ins.subs});
+    
+    % first indexing operator
+    switch itype{1}
  
       case '()'
         
-        idx = ins.subs{:};
+        idx = isubs{1};
+
         if ischar(idx) && idx == ':'
             gelp = gstruct.el(1:end);
         elseif length(idx) == 1 
@@ -38,4 +44,30 @@
         
     end
   
+    % pass additional element indexing to element subsref method
+    if length(itype) > 1
+        eins.type = itype{2};
+        eins.subs = isubs{2};
+        if iscell(gelp)
+            gelp = cellfun(@(x)subsref(x, eins), gelp, 'Un',0); 
+        else
+            gelp = subsref(gelp, eins); 
+        end
+    end
+    
+    % flatten a cell array
+    function fca = flatten(ca)
+        
+        fca = cell(size(ca));
+    
+        for k = 1:length(ca)
+            if iscell(ca{k})
+                ct = ca{k};
+                fca{k} = ct{1};
+            else
+                fca(k) = ca(k);
+            end
+        end    
+    end
+    
 end  
diff --git a/Basic/gdsii_version.m b/Basic/gdsii_version.m
index ec9dc76..4788bc1 100644
--- a/Basic/gdsii_version.m
+++ b/Basic/gdsii_version.m
@@ -17,7 +17,7 @@
 
     % toolbox version and version date
     tb_version = '136';
-    tb_date = '2016-October-24';
+    tb_date = '2016-November-04';
     ltb_ver = [tb_version, '  (', tb_date, ')'];
     if exist('OCTAVE_VERSION')
         interpreter = 'Octave';
diff --git a/ChangeLog b/ChangeLog
index 437b51f..6258f11 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2016-November-05
+- version 137
+- return [] in 'get_element_data' if an element does not have a requested 
+  property instead of throwing an error.
+- improved 'subsref' methods for gds_library and gds_structure objects that
+  enable more complex indexing operations. E.g. it is now possible to
+  write S(10).xy to get the xy record of the 10th element in a
+  structure without having to copy the element first.
+
 2016-October-24
 - version 136
 - finally squashed bug in gdsio::now