From 6c1414b915f927fc6b83a192a9ff8345da64be82 Mon Sep 17 00:00:00 2001
From: James Mitchell <jdm3@st-andrews.ac.uk>
Date: Tue, 29 Sep 2026 10:20:10 +0100
Subject: [PATCH 1/2] Resolve Issue 75

---
 gap/dot.gi               | 21 ++++++++++++++++++++-
 tst/dot.tst              | 12 +++++++++++-
 tst/examples/structs.tst | 20 ++++++++++----------
 3 files changed, 41 insertions(+), 12 deletions(-)

diff --git a/gap/dot.gi b/gap/dot.gi
index 384dd07..d266e0a 100644
--- a/gap/dot.gi
+++ b/gap/dot.gi
@@ -256,10 +256,29 @@ InstallMethod(GraphvizSetAttr,
 "for a graphviz node or edge, object, and object",
 [IsGraphvizNodeOrEdge, IsObject, IsObject],
 function(x, name, value)
-  GraphvizAttrs(x)[String(name)] := String(value);
+  name  := String(name);
+  value := String(value);
+  NormalizeWhitespace(name);
+  NormalizeWhitespace(value);
+  GraphvizAttrs(x)[name] := value;
   return x;
 end);
 
+InstallMethod(GraphvizSetAttr,
+"for a graphviz node or edge, and string",
+[IsGraphvizNodeOrEdge, IsString],
+function(x, str)
+  local attr;
+
+  attr := SplitString(str, "=");
+  if Length(attr) <> 2 then
+    ErrorFormatted("expected a string of the form \"attribute_name=value\", ",
+                   "but the input string {} does not contain \"=\"", str);
+  fi;
+
+  return GraphvizSetAttr(x, attr[1], attr[2]);
+end);
+
 InstallMethod(GraphvizSetAttr,
 "for a graphviz object with subobjects, object, and object",
 [IsGraphvizGraphDigraphOrContext, IsObject, IsObject],
diff --git a/tst/dot.tst b/tst/dot.tst
index 6fa19fe..fa57de9 100644
--- a/tst/dot.tst
+++ b/tst/dot.tst
@@ -8,7 +8,7 @@
 #############################################################################
 ##
 
-#@local a, b, color, e, g, gv, label, n, shape, G, D
+#@local a, b, color, e, g, gv, label, n, shape, G, D, innode, f
 gap> START_TEST("graphviz package: dot.tst");
 gap> LoadPackage("GraphvizForGAP", false);;
 
@@ -229,5 +229,15 @@ gap> GraphvizNodes(g); AsString(g);
 rec( a := <graphviz node "a">, b := <graphviz node "b"> )
 "//dot\ndigraph unexpected {\n\ta\n\tb\n\ta -> b\n\tb -> a\n}\n"
 
+# Issue 75
+gap> f := GraphvizDigraph("blah");
+<graphviz digraph "blah" with 0 nodes and 0 edges>
+gap> GraphvizSetAttr(f, "rankdir", "min");
+<graphviz digraph "blah" with 0 nodes and 0 edges>
+gap> innode := GraphvizAddNode(f, "in");
+<graphviz node "in">
+gap> GraphvizSetAttr(innode, "shape= \"none\"");
+<graphviz node "in">
+
 #
 gap> STOP_TEST("graphviz package: dot.tst", 0);
diff --git a/tst/examples/structs.tst b/tst/examples/structs.tst
index 2d6492d..3429ad6 100644
--- a/tst/examples/structs.tst
+++ b/tst/examples/structs.tst
@@ -65,16 +65,16 @@ gap> GraphvizAddEdge(s, "struct1:f2", "struct3:here");
 #
 gap> AsString(s);
 "//dot\ndigraph structs {\n\tnode [shape=\"plaintext\"] \n\tstruct1 [label=<<T\
-ABLE BORDER=\"0\" CELLBORDER=\"1\" CELLSPACING=\"0\">\n<TR>\n<TD>left</TD>\n<T\
-D PORT=\"f1\">middle</TD><TD PORT=\"f2\">right</TD>\n</TR>\n</TABLE>>]\n\tstru\
-ct2 [label=<<TABLE BORDER=\"0\" CELLBORDER=\"1\" CELLSPACING=\"0\">\n<TR>\n<TD\
- PORT=\"f0\">one</TD>\n<TD>two</TD>\n</TR>\n</TABLE>>]\n\tstruct3 [label=<<TAB\
-LE BORDER=\"0\" CELLBORDER=\"1\" CELLSPACING=\"0\" CELLPADDING=\"4\">\n<TR>\n<\
-TD ROWSPAN=\"3\">hello<BR/>world</TD>\n<TD COLSPAN=\"3\">b</TD>\n<TD ROWSPAN=\
-\"3\">g</TD>\n<TD ROWSPAN=\"3\">h</TD>\n</TR>\n<TR>\n<TD>c</TD>\n<TD PORT=\"he\
-re\">d</TD>\n<TD>e</TD>\n</TR>\n<TR>\n<TD COLSPAN=\"3\">f</TD>\n</TR>\n</TABLE\
->>]\n\tstruct1:f1\n\tstruct2:f0\n\tstruct1:f1 -> struct2:f0\n\tstruct1:f2\n\ts\
-truct3:here\n\tstruct1:f2 -> struct3:here\n}\n"
+ABLE BORDER=\"0\" CELLBORDER=\"1\" CELLSPACING=\"0\"> <TR> <TD>left</TD> <TD P\
+ORT=\"f1\">middle</TD><TD PORT=\"f2\">right</TD> </TR> </TABLE>>]\n\tstruct2 [\
+label=<<TABLE BORDER=\"0\" CELLBORDER=\"1\" CELLSPACING=\"0\"> <TR> <TD PORT=\
+\"f0\">one</TD> <TD>two</TD> </TR> </TABLE>>]\n\tstruct3 [label=<<TABLE BORDER\
+=\"0\" CELLBORDER=\"1\" CELLSPACING=\"0\" CELLPADDING=\"4\"> <TR> <TD ROWSPAN=\
+\"3\">hello<BR/>world</TD> <TD COLSPAN=\"3\">b</TD> <TD ROWSPAN=\"3\">g</TD> <\
+TD ROWSPAN=\"3\">h</TD> </TR> <TR> <TD>c</TD> <TD PORT=\"here\">d</TD> <TD>e</\
+TD> </TR> <TR> <TD COLSPAN=\"3\">f</TD> </TR> </TABLE>>]\n\tstruct1:f1\n\tstru\
+ct2:f0\n\tstruct1:f1 -> struct2:f0\n\tstruct1:f2\n\tstruct3:here\n\tstruct1:f2\
+ -> struct3:here\n}\n"
 
 #
 gap> STOP_TEST("graphviz package: examples/structs.tst");

From 29e83fec4a9b282ff03f117a04fd8d2e0f12bd86 Mon Sep 17 00:00:00 2001
From: James Mitchell <jdm3@st-andrews.ac.uk>
Date: Tue, 29 Sep 2026 10:34:59 +0100
Subject: [PATCH 2/2] Increase line length to 100

---
 .gaplint.yml  | 1 +
 PackageInfo.g | 2 +-
 gap/dot.gd    | 3 ++-
 3 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/.gaplint.yml b/.gaplint.yml
index a6e81f9..649e05c 100644
--- a/.gaplint.yml
+++ b/.gaplint.yml
@@ -1,2 +1,3 @@
 disable:
   - align-assignments
+columns: 100
diff --git a/PackageInfo.g b/PackageInfo.g
index 8c67a2a..e380876 100644
--- a/PackageInfo.g
+++ b/PackageInfo.g
@@ -45,7 +45,7 @@ Persons := [
 Status := "dev",
 
 SourceRepository := rec(Type := "git",
-                        URL  := "https://github.com/gap-packages/GraphvizForGAP"),
+                        URL := "https://github.com/gap-packages/GraphvizForGAP"),
 IssueTrackerURL := Concatenation(~.SourceRepository.URL, "/issues"),
 PackageWWWHome  := "https://gap-packages.github.io/GraphvizForGAP/",
 
diff --git a/gap/dot.gd b/gap/dot.gd
index c09bee8..0f0e43a 100644
--- a/gap/dot.gd
+++ b/gap/dot.gd
@@ -403,7 +403,8 @@ DeclareOperation("GraphvizSetName",
 #! @Returns a &GAPGraphviz; node object
 #! @Description Adds a node to the graph.
 #! If a node with the same name is already present the operation fails.
-#! What constitute a valid <A>node</A> name is found at https://graphviz.org/doc/info/lang.html
+#! What constitute a valid <A>node</A> name is found at
+#! https://graphviz.org/doc/info/lang.html
 #! @BeginExampleSession
 #! @EndExampleSession
 DeclareOperation("GraphvizAddNode",