Fix runtime error backtrace printing for function call

parse.leg

@@ -957,22 +957,20 @@ void printBacktrace(oop top)
     fflush(stdout);
     printLocation(top);
     while (CallArray_position(&backtrace) > 0) {
-    struct Call call= CallArray_pop(&backtrace);
-    if (is(Map, call.ast) && Call_proto == map_get(call.ast, __proto___symbol)) {
-        oop name= get(call.function, Function, name);
-        if (null != name) {
-        printf(" in ");
-        if (get(call.function, Function, primitive))
-            printf("primitive ");
-        else
-            printf("function ");
-        println(get(call.function, Function, name));
+        struct Call call= CallArray_pop(&backtrace);
+        if (is(Map, call.ast) && Call_proto == map_get(call.ast, __proto___symbol)) {
+            oop name= get(call.function, Function, name);
+            if (null != name) {
+                printf(" in ");
+                if (get(call.function, Function, primitive)) printf("primitive ");
+                else printf("function ");
+                println(get(call.function, Function, name));
+            }
         }
-    }
-    else {
-        printf("\n");
-    }
-    printLocation(call.ast);
+        else {
+            printf("\n");
+        }
+        printLocation(call.ast);
     }
     printf("\n");
 }
@@ -1353,10 +1351,8 @@ oop eval(oop scope, oop ast)
     case t_Call: {
         oop func = eval(scope, map_get(ast, func_symbol));
         if (!is(Function, func)) {
-            // TODO better error printing
-            // Please search for ISSUE1 in parse.leg
-            printf("cannot call ");
-            println(func);
+            printf("\ncannot call %s\n", printString(func));
+            printBacktrace(ast);
             exit(1);
         }
 
@@ -1413,8 +1409,8 @@ oop eval(oop scope, oop ast)
         oop this = eval(scope, map_get(ast, this_symbol));
         oop func = getVariable(this, map_get(ast, name_symbol));
         if (!is(Function, func)) {
-            printf("cannot invoke ");
-            println(func);
+            printf("\ncannot invoke %s\n", printString(func));
+            printBacktrace(ast);
             exit(1);
         }
 
@@ -1797,22 +1793,14 @@ oop prim_length(oop scope, oop params)
     return null;
 }
 
-// TODO
-// ISSUE1: how can I handle the "cannot invoke " with nice printing the func name and its args
-// it would be really nice to have a toString() function (that would be directly used in print())
-// but it seems that it's really complicated to write a toString() for integer, function and maps...
-// please see the draft line 490 in object.c
-
-// ISSUE2: how can I tackle the 2 fprintf(stderr, "\nbreak/continue oustide of a loop\n") in prim_invoke and prim_apply
-// in this situation it seems that I don't have access to any AST
 oop prim_invoke(oop scope, oop params)
 {
     oop this= null;      if (map_hasIntegerKey(params, 0)) this=  get(params, Map, elements)[0].value;
     oop func= null;      if (map_hasIntegerKey(params, 1)) func=  get(params, Map, elements)[1].value;
     oop args= null;      if (map_hasIntegerKey(params, 2)) args=  get(params, Map, elements)[2].value;
     if (!is(Function, func)) {
-        printf("cannot invoke ");
-        println(func);
+        printf("\ncannot invoke %s\n", printString(func));
+        printBacktrace(mrAST);
         exit(1);
     }
     if (NULL != get(func, Function, primitive)) {
@@ -1852,8 +1840,8 @@ oop prim_invoke(oop scope, oop params)
 oop apply(oop scope, oop func, oop args)
 {
     if (!is(Function, func)) {
-        printf("cannot apply ");
-        println(func);
+        printf("\ncannot apply %s\n", printString(func));
+        printBacktrace(mrAST);
         exit(1);
     }
     if (NULL != get(func, Function, primitive)) {
@@ -1964,8 +1952,7 @@ void readEvalPrint(oop scope, char *fileName)
         case j_continue:
             runtimeError("continue outside of a loop");
         case j_throw:
-            printf("\nunhandled exception: ");
-            println(res);
+            printf("\nunhandled exception: %s\n", printString(res));
             printBacktrace(mrAST);
             exit(1);
     }