Reorganized the file into two parts. The top section consists of

functions which understand the internal layout of the Groups
structure.  The remaining functions only use the functional interface.
This was necessary as I needed to modify the Groups structure (in a
backward compatible way) to include tensor type tags.  So now instead of

{"groupname", {var1, var2, ...}}

we can now have

{"groupname", {var1, var2,...}, Tags -> {TensorType -> "DD", TensorWeight -> -1/2}}

for example. The rest of Kranc should use ONLY the functions at the
top of this file to manipulate Groups structures. KrancThorn and
CalculationFunction will satisfy this requirement, but I am no longer
maintaining KrancThorns.m, so it won't be able to cope with the
modified group format.

1 files changed, 93 insertions, 16 deletions

diff --git a/Tools/CodeGen/KrancGroups.m b/Tools/CodeGen/KrancGroups.m
index 3daa147..a94a11e 100644
--- a/Tools/CodeGen/KrancGroups.m
+++ b/Tools/CodeGen/KrancGroups.m
@@ -28,8 +28,9 @@ BeginPackage["sym`"];
 EndPackage[];
 
 BeginPackage["KrancGroups`", 
-             {"sym`", "Errors`"}];
+             {"sym`", "Errors`", "MapLookup`"}];
 
+CreateGroup;
 groupsFromGFs::usage = "";
 addrhs::usage = "";
 variablesInGroup::usage = "";
@@ -45,14 +46,84 @@ implementationFromGroupName::usage = "";
 qualifyGroups::usage = "";
 containingGroups::usage = "";
 groupVariables::usage = "";
+GroupTags::usage = "";
+SetGroupVariables;
+VerifyGroup;
+VerifyGroupName;
+SetGroupName;
 
 Begin["`Private`"];
 
+(* The Group structure is of the following form, but the user should
+not assume this. All interaction with Group structures should be
+through this file.  This way, we can modify the underlying
+representation without other code having to be rewritten.
+
+{name, {vars}, extras...}
+
+The extras can be any of the following:
+
+Tags -> {tag1, tag2, ...}
+
+
+
+  *)
+
+(*********************************************************************)
+(* The following functions know about the internal form of a Group
+   structure*)
+(*********************************************************************)
+
+CreateGroup[name_, vars_, extras_] :=
+  Module[{g},
+    VerifyGroupName[name];
+    VerifyList[vars];
+    VerifyList[extras];
+    g = Join[{name, vars}, extras];
+    InfoMessage[Full, "Created group: ", g];
+    Return[g]];
+
+
+VerifyGroup[group_] :=
+  Module[{},
+    If[!ListQ[group] || Length[group] < 2 || !StringQ[group[[1]]] || ! ListQ[group[[2]]],
+      ThrowError["Not a group definition:", group],
+      True]];
+
+VerifyGroupName[groupName_] :=
+  If[!StringQ[groupName],
+    ThrowError["Not a group name:", groupName],
+    True];
+
+
+groupName[g_] := First[g];
+
+groupVariables[group_] :=
+  group[[2]];
+
+GroupTags[g_] :=
+  Module[{extras},
+    extras = Drop[g, 2];
+    lookupDefault[extras, Tags, {}]];
+
+SetGroupName[g_, n_] :=
+  Join[{n}, Drop[g, 1]];
+
+SetGroupVariables[g_, vars_] :=
+  Module[{},
+    Join[{groupName[g], vars}, Drop[g, 2]]];
+
+(*********************************************************************)
+(* The following functions DO NOT KNOW about the internal form of a Group
+   structure*)
+(*********************************************************************)
+
+
 (* Return those group structures which contain any variables in GFs *)
 groupsFromGFs[groups_, GFs_] := Module[{inter, check},
   (* Given a group structure, return those variables from it that are in
      GFs *)
-  inter[y_] :=  Intersection[Last@y, Flatten@GFs];
+  inter[y_] :=  Intersection[groupVariables[y], GFs]; (* The last arg was flattened; why? *)
 
   (* Check whether the group structure y contains any variables in GFs *)
   check[y_] := TrueQ[Length@inter[y] > 0];
@@ -60,24 +131,35 @@ groupsFromGFs[groups_, GFs_] := Module[{inter, check},
   Select[groups, check]
 ];
 
+renameGroup[g_, newName_] :=
+  SetGroupName[g, newName];
+
 addrhs[x_] := ToString[x] <> "rhs";
 
 variablesInGroup[name_, groups_] :=
-  Last[groupFromName[name, groups]];
+  groupVariables[groupFromName[name, groups]];
 
-groupVariables[group_] :=
-  Last[group];
 
 evolvedGroupToRHSGroup[name_, groups_] := 
-  Module[{group = First[Select[groups, groupName[#] === name &]]},
-    {addrhs[name], Map[Symbol[addrhs[ToString[#]]] &, Last[group]]}];
+  Module[{names, group},
+    names = Map[groupName, groups];
+    If[!MemberQ[names, name], ThrowError["evolvedGroupToRHSGroup: Group \"" <> groupName <> "\" not found in groups structure:", groups]];
+
+    group = First[Select[groups, groupName[#] === name &]];
+
+    oldVars = groupVariables[group];
+    newVars = Map[Symbol[addrhs[ToString[#]]] &, oldVars];
+
+    group = SetGroupName[group, addrhs[name]];
+    group = SetGroupVariables[group, newVars];
+    Return[group]];
 
 variablesFromGroups[groupNames_, groups_] := 
   Flatten[Map[variablesInGroup[#, groups] &, groupNames], 1];
 
 groupFromName[name_, groups_] :=
   Module[{gs},
-    gs = Select[groups, First[#] === name &];
+    gs = Select[groups, groupName[#] === name &];
     If[Length[gs] == 0,
        ThrowError["Cannot find group ", name, "in", groups]];
     If[Length[gs] > 1,
@@ -85,11 +167,6 @@ groupFromName[name_, groups_] :=
 
     First[gs]];
 
-groupName[g_] := First[g];
-
-renameGroup[{name_, vars_}, newName_] :=
-  {newName, vars};
-
 qualifyGroupName[name_, defaultImp_] :=
   If[StringMatchQ[name, "*::*"],
      name,
@@ -132,9 +209,9 @@ containingGroups[vars_, groups_] :=
   Module[{allVars},
     allVars = Apply[Join, Map[variablesInGroup, groups]];
     Map[If[!MemberQ[allVars, #],
-           Throw[ToString[#] <> 
-                 " is not a member of any of the following groups: " <> 
-                 ToString[groups]]] &, vars];
+           ThrowError[ToString[#] <> 
+                 " is not a member of any of the following groups: ",
+                 groups]] &, vars];
 
     Union[Map[groupName, Select[groups, Intersection[variablesInGroup[#], vars] != {} &]]]];