WIP

src/stats.c

@@ -260,7 +260,7 @@ UInt            ExecIfElif (
     for ( i = 1; i <= nr; i++ ) {
 
         /* if the condition evaluates to 'true', execute the branch body   */
-        SET_BRK_CURR_STAT( stat );
+//         SET_BRK_CURR_STAT( stat );
         cond = ADDR_STAT(stat)[2*(i-1)];
         if ( EVAL_BOOL_EXPR( cond ) != False ) {
 
@@ -291,7 +291,7 @@ UInt            ExecIfElifElse (
     for ( i = 1; i <= nr; i++ ) {
 
         /* if the condition evaluates to 'true', execute the branch body   */
-        SET_BRK_CURR_STAT( stat );
+        // SET_BRK_CURR_STAT( stat );
         cond = ADDR_STAT(stat)[2*(i-1)];
         if ( EVAL_BOOL_EXPR( cond ) != False ) {
 
@@ -368,7 +368,6 @@ static ALWAYS_INLINE UInt ExecForHelper(Stat stat, UInt nr)
     }
 
     /* evaluate the list                                                   */
-    SET_BRK_CURR_STAT( stat );
     list = EVAL_EXPR( ADDR_STAT(stat)[1] );
 
     /* get the body                                                        */
@@ -512,7 +511,6 @@ static ALWAYS_INLINE UInt ExecForRangeHelper(Stat stat, UInt nr)
     lvar = LVAR_REFLVAR( ADDR_STAT(stat)[0] );
 
     /* evaluate the range                                                  */
-    SET_BRK_CURR_STAT( stat );
     VisitStatIfHooked(ADDR_STAT(stat)[1]);
     elm = EVAL_EXPR( ADDR_EXPR( ADDR_STAT(stat)[1] )[0] );
     while ( ! IS_INTOBJ(elm) ) {
@@ -682,8 +680,12 @@ static ALWAYS_INLINE UInt ExecWhileHelper(Stat stat, UInt nr)
     if (nr >= 3)
         body3 = ADDR_STAT(stat)[3];
 
+    // HACK: point current "statement" at the condition expression, so
+    // that if there is an error in it, it resp. its location is printed,
+    // not the whole loop statement.
+    SET_BRK_CALL_TO(cond);
+
     /* while the condition evaluates to 'true', execute the body           */
-    SET_BRK_CURR_STAT( stat );
     while ( EVAL_BOOL_EXPR( cond ) != False ) {
 
 #if !defined(HAVE_SIGNAL)
@@ -700,8 +702,10 @@ static ALWAYS_INLINE UInt ExecWhileHelper(Stat stat, UInt nr)
         if (nr >= 3)
             EXEC_STAT_IN_LOOP(body3);
 
-        SET_BRK_CURR_STAT( stat );
-
+        // HACK: point current "statement" at the condition expression, so
+        // that if there is an error in it, it resp. its location is printed,
+        // not the whole loop statement.
+        SET_BRK_CALL_TO(cond);
     }
 
     /* return 0 (to indicate that no leave-statement was executed)         */
@@ -759,7 +763,6 @@ static ALWAYS_INLINE UInt ExecRepeatHelper(Stat stat, UInt nr)
         body3 = ADDR_STAT(stat)[3];
 
     /* execute the body until the condition evaluates to 'true'            */
-    SET_BRK_CURR_STAT( stat );
     do {
 
 #if !defined(HAVE_SIGNAL)
@@ -776,7 +779,10 @@ static ALWAYS_INLINE UInt ExecRepeatHelper(Stat stat, UInt nr)
         if (nr >= 3)
             EXEC_STAT_IN_LOOP(body3);
 
-        SET_BRK_CURR_STAT( stat );
+        // HACK: point current "statement" at the condition expression, so
+        // that if there is an error in it, it resp. its location is printed,
+        // not the whole loop statement.
+        SET_BRK_CALL_TO(cond);
 
     } while ( EVAL_BOOL_EXPR( cond ) == False );
 
@@ -931,7 +937,10 @@ UInt ExecAssert2Args (
           "you may 'return true;' or 'return false;'");
         }
         if ( decision == False ) {
-            SET_BRK_CURR_STAT( stat );
+            // make sure the error back trace prints again at the statement,
+            // not any subexpression
+            SET_BRK_CALL_TO( stat );
+
             ErrorReturnVoid( "Assertion failure", 0L, 0L, "you may 'return;'");
         }
 
@@ -971,6 +980,7 @@ UInt ExecAssert3Args (
         if ( decision == False ) {
             message = EVAL_EXPR(ADDR_STAT( stat )[2]);
             if ( message != (Obj) 0 ) {
+                SET_BRK_CALL_TO( stat );
                 if (IS_STRING_REP( message ))
                     PrintString1( message );
                 else

tst/test-error/backtrace.g

@@ -0,0 +1,20 @@
+f := function() 
+  local l;
+  l := 0 * [1..6];
+  l[[1..3]] := 1;
+end;
+f();
+Where();
+quit;
+
+
+f:=function() if true = 1/0 then return 1; fi; return 2; end;;
+f();
+Where();
+quit;
+
+
+f:=function() if 1 then return 1; fi; return 2; end;;
+f();
+Where();
+quit;

tst/test-error/backtrace.g.out

@@ -0,0 +1,32 @@
+gap> f := function() 
+>   local l;
+>   l := 0 * [1..6];
+>   l[[1..3]] := 1;
+> end;
+function(  ) ... end
+gap> f();
+Error, no method found! For debugging hints type ?Recovery from NoMethodFound
+Error, no 1st choice method found for `[]:=' on 3 arguments at GAPROOT/lib/methsel2.g:250 called from
+l[[ 1 .. 3 ]] := 1; at *stdin*:5 called from
+<function "f">( <arguments> )
+ called from read-eval loop at *stdin*:7
+type 'quit;' to quit to outer loop
+brk> Where();
+l[[ 1 .. 3 ]] := 1; at *stdin*:5 called from
+<function "f">( <arguments> )
+ called from read-eval loop at *errin*:1
+brk> quit;
+gap> 
+gap> 
+gap> f:=function() if true = 1/0 then return 1; fi; return 2; end;;
+gap> f();
+Error, Rational operations: <divisor> must not be zero in
+  1 / 0 at *stdin*:9 called from 
+<function "f">( <arguments> )
+ called from read-eval loop at *stdin*:10
+you can replace <divisor> via 'return <divisor>;'
+brk> Where();
+<function "f">( <arguments> )
+ called from read-eval loop at *errin*:1
+brk> quit;
+gap> QUIT;

tst/test-error/bad-array-int-0.g.out

@@ -7,7 +7,7 @@ function(  ) ... end
 gap> f();
 Error, no method found! For debugging hints type ?Recovery from NoMethodFound
 Error, no 1st choice method found for `[]' on 2 arguments at GAPROOT/lib/methsel2.g:250 called from
-l[0] at *stdin*:5 called from
+return l[0]; at *stdin*:5 called from
 <function "f">( <arguments> )
  called from read-eval loop at *stdin*:7
 type 'quit;' to quit to outer loop

tst/test-error/bad-array-int-1.g.out

@@ -4,7 +4,7 @@ gap> f := function()
 function(  ) ... end
 gap> f();
 Error, List Element: <list> must be a list (not a integer) in
-  1[1] at *stdin*:3 called from 
+  return 1[1]; at *stdin*:3 called from 
 <function "f">( <arguments> )
  called from read-eval loop at *stdin*:5
 you can replace <list> via 'return <list>;'

tst/test-error/bad-array-string.g.out

@@ -5,7 +5,7 @@ function(  ) ... end
 gap> f();
 Error, no method found! For debugging hints type ?Recovery from NoMethodFound
 Error, no 1st choice method found for `[]' on 2 arguments at GAPROOT/lib/methsel2.g:250 called from
-1["abc"] at *stdin*:3 called from
+return 1["abc"]; at *stdin*:3 called from
 <function "f">( <arguments> )
  called from read-eval loop at *stdin*:5
 type 'quit;' to quit to outer loop