add replace function (#306)

Co-authored-by: Felix Maier <fm41@mailbox.org>

README.md

@@ -212,6 +212,9 @@ render("Hello {{ upper(neighbour) }}!", data); // "Hello PETER!"
 render("Hello {{ lower(neighbour) }}!", data); // "Hello peter!"
 render("Hello {{ capitalize(neighbour) }}!", data); // "Hello Peter!"
 
+// Replace characters in a string
+render("{{ replace(neighbour, \"e\", \"3\")}}", data); // "P3t3r"
+
 // Range function, useful for loops
 render("{% for i in range(4) %}{{ loop.index1 }}{% endfor %}", data); // "1234"
 render("{% for i in range(3) %}{{ at(guests, i) }} {% endfor %}", data); // "Jeff Tom Patrick "

include/inja/function_storage.hpp

@@ -63,6 +63,7 @@ public:
     Min,
     Odd,
     Range,
+    Replace,
     Round,
     Sort,
     Upper,
@@ -106,6 +107,7 @@ private:
       {std::make_pair("min", 1), FunctionData {Operation::Min}},
       {std::make_pair("odd", 1), FunctionData {Operation::Odd}},
       {std::make_pair("range", 1), FunctionData {Operation::Range}},
+      {std::make_pair("replace", 3), FunctionData {Operation::Replace}},
       {std::make_pair("round", 2), FunctionData {Operation::Round}},
       {std::make_pair("sort", 1), FunctionData {Operation::Sort}},
       {std::make_pair("upper", 1), FunctionData {Operation::Upper}},

include/inja/renderer.hpp

@@ -414,6 +414,12 @@ class Renderer : public NodeVisitor {
       std::iota(result.begin(), result.end(), 0);
       make_result(std::move(result));
     } break;
+    case Op::Replace: {
+      const auto args = get_arguments<3>(node);
+      auto result = args[0]->get<std::string>();
+      replace_substring(result, args[1]->get<std::string>(), args[2]->get<std::string>());
+      make_result(std::move(result));
+    } break;
     case Op::Round: {
       const auto args = get_arguments<2>(node);
       const auto precision = args[1]->get<const json::number_integer_t>();

single_include/inja/inja.hpp

@@ -170,6 +170,7 @@ public:
     Min,
     Odd,
     Range,
+    Replace,
     Round,
     Sort,
     Upper,
@@ -213,6 +214,7 @@ private:
       {std::make_pair("min", 1), FunctionData {Operation::Min}},
       {std::make_pair("odd", 1), FunctionData {Operation::Odd}},
       {std::make_pair("range", 1), FunctionData {Operation::Range}},
+      {std::make_pair("replace", 3), FunctionData {Operation::Replace}},
       {std::make_pair("round", 2), FunctionData {Operation::Round}},
       {std::make_pair("sort", 1), FunctionData {Operation::Sort}},
       {std::make_pair("upper", 1), FunctionData {Operation::Upper}},
@@ -2521,6 +2523,12 @@ class Renderer : public NodeVisitor {
       std::iota(result.begin(), result.end(), 0);
       make_result(std::move(result));
     } break;
+    case Op::Replace: {
+      const auto args = get_arguments<3>(node);
+      auto result = args[0]->get<std::string>();
+      replace_substring(result, args[1]->get<std::string>(), args[2]->get<std::string>());
+      make_result(std::move(result));
+    } break;
     case Op::Round: {
       const auto args = get_arguments<2>(node);
       const auto precision = args[1]->get<const json::number_integer_t>();

test/test-functions.cpp

@@ -108,6 +108,11 @@ TEST_CASE("functions") {
     // [json.exception.type_error.302] type must be array, but is number" );
   }
 
+  SUBCASE("replace") {
+    CHECK(env.render("{{ replace(name, \"e\", \"3\") }}", data) == "P3t3r");
+    CHECK(env.render("{{ replace(city, \" \", \"_\") }}", data) == "New_York");
+  }
+
   SUBCASE("round") {
     CHECK(env.render("{{ round(4, 0) }}", data) == "4");
     CHECK(env.render("{{ round(temperature, 2) }}", data) == "25.68");