SEXP attribute_hidden do_sysbrowser(/*const*/ Expression* call, const BuiltInFunction* op, RObject* n_) { int n; n = asInteger(n_); if(n < 1 ) error(_("number of contexts must be positive")); switch (op->variant()) { case 1: /* text */ case 2: /* condition */ { if (n > int(Browser::numberActive())) { if (n == 1) Rf_error(_("no browser context to query")); else Rf_error(_("not that many calls to browser are active")); } Browser* browser = Browser::fromOutermost(Browser::numberActive() - n); return op->variant() == 1 ? browser->text() : browser->condition(); } break; case 3: /* turn on debugging n levels up */ { if (Browser::numberActive() == 0) Rf_error(_("no browser context to query")); Browser* browser = Browser::fromOutermost(Browser::numberActive() - 1); ClosureContext* cptr = ClosureContext::innermost(browser->context()); while (cptr && n > 1) { n--; cptr = ClosureContext::innermost(cptr->nextOut()); } if (!cptr) error(_("not that many functions on the call stack")); else { SET_RDEBUG(cptr->workingEnvironment(), TRUE); } } break; } return nullptr; }