feat: jinja engine improvements for reka-edge

common/jinja/runtime.cpp

@@ -251,6 +251,22 @@ value binary_expression::execute_impl(context & ctx) {
         return res;
     }
 
+    // Python-style string repetition
+    if (op.value == "*" &&
+            ((is_val<value_string>(left_val) && is_val<value_int>(right_val)) ||
+             (is_val<value_int>(left_val) && is_val<value_string>(right_val)))) {
+        const auto & str = is_val<value_string>(left_val) ? left_val->as_string() : right_val->as_string();
+        const int64_t repeat = is_val<value_int>(right_val) ? right_val->as_int() : left_val->as_int();
+        auto res = mk_val<value_string>();
+        if (repeat <= 0) {
+            return res;
+        }
+        for (int64_t i = 0; i < repeat; ++i) {
+            res->val_str = res->val_str.append(str);
+        }
+        return res;
+    }
+
     // String membership
     if (is_val<value_string>(left_val) && is_val<value_string>(right_val)) {
         // case: "a" in "abc"

common/jinja/value.cpp

@@ -1,4 +1,5 @@
 #include "runtime.h"
+#include "unicode.h"
 #include "value.h"
 
 // for converting from JSON to jinja values
@@ -154,6 +155,83 @@ static value test_compare_fn(const func_args & args) {
     return mk_val<value_bool>(value_compare(args.get_pos(0), args.get_pos(1), op));
 }
 
+static void append_codepoint_as_ascii_json_escape(std::string & out, uint32_t codepoint) {
+    auto append_u16 = [&out](uint32_t value) {
+        char buf[7];
+        snprintf(buf, sizeof(buf), "\\u%04x", static_cast<unsigned int>(value));
+        out += buf;
+    };
+
+    if (codepoint <= 0xFFFF) {
+        append_u16(codepoint);
+        return;
+    }
+
+    codepoint -= 0x10000;
+    append_u16(0xD800 + ((codepoint >> 10) & 0x3FF));
+    append_u16(0xDC00 + (codepoint & 0x3FF));
+}
+
+static std::string json_ensure_ascii_preserving_format(const std::string & json_str) {
+    std::string output;
+    output.reserve(json_str.size());
+
+    bool in_string = false;
+    bool escaped = false;
+
+    for (size_t pos = 0; pos < json_str.size();) {
+        const char ch = json_str[pos];
+        if (!in_string) {
+            output.push_back(ch);
+            if (ch == '"') {
+                in_string = true;
+            }
+            ++pos;
+            continue;
+        }
+
+        if (escaped) {
+            output.push_back(ch);
+            escaped = false;
+            ++pos;
+            continue;
+        }
+
+        if (ch == '\\') {
+            output.push_back(ch);
+            escaped = true;
+            ++pos;
+            continue;
+        }
+
+        if (ch == '"') {
+            output.push_back(ch);
+            in_string = false;
+            ++pos;
+            continue;
+        }
+
+        const unsigned char uch = static_cast<unsigned char>(ch);
+        if (uch < 0x80) {
+            output.push_back(ch);
+            ++pos;
+            continue;
+        }
+
+        auto parsed = common_parse_utf8_codepoint(json_str, pos);
+        if (parsed.status != utf8_parse_result::SUCCESS) {
+            output += "\\ufffd";
+            ++pos;
+            continue;
+        }
+
+        append_codepoint_as_ascii_json_escape(output, parsed.codepoint);
+        pos += parsed.bytes_consumed;
+    }
+
+    return output;
+}
+
 static value tojson(const func_args & args) {
     args.ensure_count(1, 5);
     value val_ascii      = args.get_kwarg_or_pos("ensure_ascii", 1);
@@ -169,16 +247,17 @@ static value tojson(const func_args & args) {
     if (is_val<value_int>(val_indent)) {
         indent = static_cast<int>(val_indent->as_int());
     }
-    if (val_ascii->as_bool()) { // undefined == false
-        throw not_implemented_exception("tojson ensure_ascii=true not implemented");
-    }
     if (val_sort->as_bool()) { // undefined == false
         throw not_implemented_exception("tojson sort_keys=true not implemented");
     }
+    const bool ensure_ascii = val_ascii->as_bool(); // undefined == false
     auto separators = (is_val<value_array>(val_separators) ? val_separators : mk_val<value_array>())->as_array();
     std::string item_sep = separators.size() > 0 ? separators[0]->as_string().str() : (indent < 0 ? ", " : ",");
     std::string key_sep = separators.size() > 1 ? separators[1]->as_string().str() : ": ";
     std::string json_str = value_to_json(args.get_pos(0), indent, item_sep, key_sep);
+    if (ensure_ascii) {
+        json_str = json_ensure_ascii_preserving_format(json_str);
+    }
     return mk_val<value_string>(json_str);
 }
 
@@ -460,6 +539,10 @@ const func_builtins & value_int_t::get_builtins() const {
             int64_t val = args.get_pos(0)->as_int();
             return mk_val<value_int>(val < 0 ? -val : val);
         }},
+        {"int", [](const func_args & args) -> value {
+            args.ensure_vals<value_int>();
+            return mk_val<value_int>(args.get_pos(0)->as_int());
+        }},
         {"float", [](const func_args & args) -> value {
             args.ensure_vals<value_int>();
             double val = static_cast<double>(args.get_pos(0)->as_int());

tests/test-jinja.cpp

@@ -447,6 +447,18 @@ static void test_expressions(testing & t) {
         "hello world"
     );
 
+    test_template(t, "string repetition",
+        "{{ 'ab' * 3 }}",
+        json::object(),
+        "ababab"
+    );
+
+    test_template(t, "reversed string repetition",
+        "{{ 3 * 'ab' }}",
+        json::object(),
+        "ababab"
+    );
+
     test_template(t, "ternary",
         "{{ 'yes' if cond else 'no' }}",
         {{"cond", true}},
@@ -693,6 +705,39 @@ static void test_filters(testing & t) {
         "\"\\u2713\""
     );
 
+    test_template(t, "tojson ensure_ascii=true nested object",
+        "{{ data|tojson(ensure_ascii=true) }}",
+        {{"data", {
+            {"text", "\u2713"},
+            {"items", json::array({"é", {{"snowman", "☃"}}})}
+        }}},
+        "{\"text\": \"\\u2713\", \"items\": [\"\\u00e9\", {\"snowman\": \"\\u2603\"}]}"
+    );
+
+    test_template(t, "tojson ensure_ascii=true indent=2",
+        "{{ data|tojson(ensure_ascii=true, indent=2) }}",
+        {{"data", {
+            {"text", "\u2713"},
+            {"nested", {{"accent", "é"}}}
+        }}},
+        "{\n  \"text\": \"\\u2713\",\n  \"nested\": {\n    \"accent\": \"\\u00e9\"\n  }\n}"
+    );
+
+    test_template(t, "tojson ensure_ascii=true preserves existing escapes",
+        "{{ data|tojson(ensure_ascii=true) }}",
+        {{"data", {
+            {"emoji", "😀"},
+            {"line", "a\nb"}
+        }}},
+        "{\"emoji\": \"\\ud83d\\ude00\", \"line\": \"a\\nb\"}"
+    );
+
+    test_template(t, "tojson ensure_ascii=true with invalid utf-8",
+        "{{ data|tojson(ensure_ascii=true) }}",
+        {{"data", std::string("hello\xfe\xffworld")}},
+        "\"hello\\ufffd\\ufffdworld\""
+    );
+
     test_template(t, "tojson sort_keys=true",
         "{{ data|tojson(sort_keys=true) }}",
         {{"data", {{"b", 2}, {"a", 1}}}},
@@ -771,6 +816,12 @@ static void test_filters(testing & t) {
         "hello"
     );
 
+    test_template(t, "int filter on integer is identity",
+        "{{ value|int }}",
+        {{"value", 7}},
+        "7"
+    );
+
     test_template(t, "none to string",
         "{{ x|string }}",
         {{"x", nullptr}},