Make error output use *errout* consistently

- PRINT_CURRENT_STATEMENT now takes a stream as additional input.
- Adjust its tests accordingly.
- Make ErrorInner, Where, and WHERE consistently pass "*errout*"
to print functions

lib/error.g

@@ -50,17 +50,17 @@ BIND_GLOBAL("WHERE", function( context, depth, outercontext)
     bottom := GetBottomLVars();
     lastcontext := outercontext;
     while depth > 0  and context <> bottom do
-        PRINT_CURRENT_STATEMENT(context);
-        Print(" called from\n");
+        PRINT_CURRENT_STATEMENT("*errout*", context);
+        PrintTo("*errout*", " called from\n");
         lastcontext := context;
         context := ParentLVars(context);
         depth := depth-1;
     od;
     if depth = 0 then 
-        Print("...  ");
+        PrintTo("*errout*", "...  ");
     else
         f := ContentsLVars(lastcontext).func;
-        Print("<function \"",NAME_FUNC(f)
+        PrintTo("*errout*", "<function \"",NAME_FUNC(f)
               ,"\">( <arguments> )\n called from read-eval loop ");
     fi;
 end);
@@ -75,11 +75,11 @@ BIND_GLOBAL("Where", function(arg)
     fi;
 
     if ErrorLVars = fail or ErrorLVars = GetBottomLVars() then
-        Print("not in any function ");
+        PrintTo("*errout*", "not in any function ");
     else
         WHERE(ParentLVars(ErrorLVars),depth, ErrorLVars);
     fi;
-    Print("at ",INPUT_FILENAME(),":",INPUT_LINENUMBER(),"\n");
+    PrintTo("*errout*", "at ",INPUT_FILENAME(),":",INPUT_LINENUMBER(),"\n");
 end);
 
 OnBreak := Where;
@@ -204,7 +204,7 @@ BIND_GLOBAL("ErrorInner",
     if printThisStatement then 
         if context <> GetBottomLVars() then
             PrintTo("*errout*"," in\n  \c");
-            PRINT_CURRENT_STATEMENT(context);
+            PRINT_CURRENT_STATEMENT("*errout*", context);
             Print("\c");
             PrintTo("*errout*"," called from \n");
         else

src/error.c

@@ -152,8 +152,16 @@ Obj FuncCURRENT_STATEMENT_LOCATION(Obj self, Obj context)
     return retlist;
 }
 
-Obj FuncPRINT_CURRENT_STATEMENT(Obj self, Obj context)
+Obj FuncPRINT_CURRENT_STATEMENT(Obj self, Obj stream, Obj context)
 {
+    /* HACK: we want to redirect output */
+    int openedOutput = 1;
+    if ((IsStringConv(stream) && !OpenOutput(CSTR_STRING(stream))) ||
+        (!IS_STRING(stream) && !OpenOutputStream(stream))) {
+        Pr("Can't open output stream\n", 0L, 0L);
+        openedOutput = 0;
+    }
+
     if (context == STATE(BottomLVars))
         return 0;
 
@@ -186,6 +194,10 @@ Obj FuncPRINT_CURRENT_STATEMENT(Obj self, Obj context)
         Pr(" at %g:%d", (Int)filename, LINE_STAT(call));
     }
     SWITCH_TO_OLD_LVARS(currLVars);
+    /* HACK: close the output again */
+    if (openedOutput) {
+        CloseOutput();
+    }
     return 0;
 }
 
@@ -578,7 +590,7 @@ static StructGVarFunc GVarFuncs[] = {
     GVAR_FUNC(CALL_WITH_CATCH, 2, "func, args"),
     GVAR_FUNC(JUMP_TO_CATCH, 1, "payload"),
 
-    GVAR_FUNC(PRINT_CURRENT_STATEMENT, 1, "context"),
+    GVAR_FUNC(PRINT_CURRENT_STATEMENT, 2, "stream, context"),
     GVAR_FUNC(CURRENT_STATEMENT_LOCATION, 1, "context"),
 
     GVAR_FUNC(SetUserHasQuit, 1, "value"),

tst/testinstall/kernel/gap.tst

@@ -92,9 +92,9 @@ Error, usage: UpEnv( [ <depth> ] )
 #
 gap> CURRENT_STATEMENT_LOCATION(GetCurrentLVars());
 fail
-gap> PRINT_CURRENT_STATEMENT(GetCurrentLVars());
-gap> f:=function() PRINT_CURRENT_STATEMENT(GetCurrentLVars()); Print("\n"); end;; f();
-PRINT_CURRENT_STATEMENT( GetCurrentLVars(  ) ); at stream:1
+gap> PRINT_CURRENT_STATEMENT("*errout*", GetCurrentLVars());
+gap> f:=function() PRINT_CURRENT_STATEMENT("*errout*", GetCurrentLVars()); Print("\n"); end;; f();
+PRINT_CURRENT_STATEMENT( "*errout*", GetCurrentLVars(  ) ); at *stdin*:1
 
 #
 gap> CALL_WITH_CATCH(fail,fail);