diff --git a/common/jinja/runtime.cpp b/common/jinja/runtime.cpp index f81d98d954..8d8d80b22c 100644 --- a/common/jinja/runtime.cpp +++ b/common/jinja/runtime.cpp @@ -761,9 +761,9 @@ value member_expression::execute_impl(context & ctx) { if (is_stmt(this->property)) { auto s = cast_stmt(this->property); - value start_val = s->start_expr ? s->start_expr->execute(ctx) : mk_val(0); - value stop_val = s->stop_expr ? s->stop_expr->execute(ctx) : mk_val(arr_size); value step_val = s->step_expr ? s->step_expr->execute(ctx) : mk_val(1); + value start_val = s->start_expr ? s->start_expr->execute(ctx) : (step_val->as_int() < 0 ? mk_val(arr_size - 1) : mk_val(0)); + value stop_val = s->stop_expr ? s->stop_expr->execute(ctx) : (step_val->as_int() < 0 ? mk_val(-1) : mk_val(arr_size)); // translate to function call: obj.slice(start, stop, step) JJ_DEBUG("Member expression is a slice: start %s, stop %s, step %s", diff --git a/common/jinja/value.cpp b/common/jinja/value.cpp index 72a12f665c..cd6a36956c 100644 --- a/common/jinja/value.cpp +++ b/common/jinja/value.cpp @@ -90,14 +90,14 @@ static T slice(const T & array, int64_t start, int64_t stop, int64_t step = 1) { stop_val = std::min(stop_val, len); } } else { - start_val = len - 1; + start_val = start; if (start_val < 0) { - start_val = std::max(len + start_val, (int64_t)-1); + start_val = std::max(len + start_val, (int64_t)0); } else { start_val = std::min(start_val, len - 1); } - stop_val = -1; + stop_val = stop; if (stop_val < -1) { stop_val = std::max(len + stop_val, (int64_t)-1); } else { diff --git a/tests/test-jinja.cpp b/tests/test-jinja.cpp index 21250d04c6..7bf6791b0a 100644 --- a/tests/test-jinja.cpp +++ b/tests/test-jinja.cpp @@ -435,6 +435,24 @@ static void test_expressions(testing & t) { "('c', 'b', 'a')" ); + test_template(t, "string slice negative step", + "{{ 'abcdef'[::-2] }}", + json::object(), + "fdb" + ); + + test_template(t, "string slice negative start and step", + "{{ 'abcdef'[-1:1:-1] }}", + json::object(), + "fedc" + ); + + test_template(t, "string slice negative start, stop and step", + "{{ 'abcdef'[-1:-5:-1] }}", + json::object(), + "fedc" + ); + test_template(t, "arithmetic", "{{ (a + b) * c }}", {{"a", 2}, {"b", 3}, {"c", 4}},