Give useful names to installed methods

This makes these methods easier to understand when profiling.
We add a name both to the installed method, and the function
which calculates their rank, where present.

lib/oper1.g

@@ -389,7 +389,7 @@ BIND_GLOBAL( "INSTALL_METHOD",
           rank,
           method,
           oreqs,
-          req, reqs, match, j, k, imp, notmatch, lk;
+          req, reqs, match, j, k, imp, notmatch, lk, funcname;
 
     if IsHPCGAP then
         # TODO: once the GAP compiler supports 'atomic', use that
@@ -601,6 +601,27 @@ BIND_GLOBAL( "INSTALL_METHOD",
       fi;
     fi;
 
+    if IS_FUNCTION(method) and IsBound(HasNameFunction) and IsBound(TYPE_FUNCTION) and IsBound(TYPE_FUNCTION_WITH_NAME) and IsBound(TYPE_OPERATION_WITH_NAME) and not VAL_GVAR("HasNameFunction")(method) then
+        funcname := SHALLOW_COPY_OBJ(NAME_FUNC(opr));
+        APPEND_LIST_INTR(funcname, " ");
+        if info <> false then
+            APPEND_LIST_INTR(funcname, info);
+        else
+            APPEND_LIST_INTR(funcname, "method");
+        fi;
+        SET_NAME_FUNC(method, funcname);
+    fi;
+
+    if IS_FUNCTION(rank) and IsBound(HasNameFunction) and IsBound(TYPE_FUNCTION) and IsBound(TYPE_FUNCTION_WITH_NAME) and IsBound(TYPE_OPERATION_WITH_NAME) and not VAL_GVAR("HasNameFunction")(rank) then
+        funcname := "Priority calculation for ";
+        APPEND_LIST_INTR(funcname, NAME_FUNC(opr));
+        if info <> false then
+            APPEND_LIST_INTR(funcname, " ");
+            APPEND_LIST_INTR(funcname, info);
+        fi;
+        SET_NAME_FUNC(rank, funcname);
+    fi;
+
     # Install the method in the operation.
     INSTALL_METHOD_FLAGS( opr, info, rel, flags, rank, method );
 

tst/testinstall/method.tst

@@ -9,4 +9,22 @@ Error, required filters [ "IsInt", "IsRat", "IsCyc", "IsExtAElement",
     , "IsMultiplicativeElementWithInverse", "IsZDFRE", "IsAssociativeElement",
   "IsAdditivelyCommutativeElement", "IsCommutativeElement", "IsCyclotomic" ]
 for 1st argument do not match a declaration of Size
+
+# Check names are set correctly
+gap> cheese := NewOperation("cheese", [IsObject]);
+<Operation "cheese">
+
+# These are in lists as assignments of the form 'f := x -> x' set the name
+# of the function to 'f'
+gap> funcs := [x -> x, x -> x, x -> x];;;
+gap> ranks := [{} -> 10, {} -> 10, {} -> 10];;
+gap> SetNameFunction(funcs[3], "func3");
+gap> SetNameFunction(ranks[3], "rank3");
+gap> InstallMethod(cheese, [IsInt], ranks[1], funcs[1]);
+gap> InstallMethod(cheese, "for a list", [IsList], ranks[2], funcs[2]);
+gap> InstallMethod(cheese, "for a string", [IsString], ranks[3], funcs[3]);
+gap> List(Concatenation(funcs, ranks), NameFunction);
+[ "cheese method", "cheese for a list", "func3", 
+  "Priority calculation for cheese", 
+  "Priority calculation for cheese for a list", "rank3" ]
 gap> STOP_TEST("method.tst", 1);