diff options
| -rw-r--r-- | doc/concepts/expressions.md | 3 | ||||
| -rw-r--r-- | src/buildtool/build_engine/expression/evaluator.cpp | 11 | ||||
| -rw-r--r-- | test/buildtool/build_engine/expression/expression.test.cpp | 15 |
3 files changed, 29 insertions, 0 deletions
diff --git a/doc/concepts/expressions.md b/doc/concepts/expressions.md index c66de8bc..dcd567af 100644 --- a/doc/concepts/expressions.md +++ b/doc/concepts/expressions.md @@ -253,6 +253,9 @@ those) argument(s) to obtain the final result. a map with the members of the list as keys, and all values being `true`. +- `"reverse"` The argument has to be a list. The result is a new list + with the entries in reverse order. + - `"++"` The argument has to be a list of lists. The result is the concatenation of those lists. diff --git a/src/buildtool/build_engine/expression/evaluator.cpp b/src/buildtool/build_engine/expression/evaluator.cpp index 431792e8..1d207b3b 100644 --- a/src/buildtool/build_engine/expression/evaluator.cpp +++ b/src/buildtool/build_engine/expression/evaluator.cpp @@ -185,6 +185,16 @@ auto Set(ExpressionPtr const& expr) -> ExpressionPtr { return ExpressionPtr{Expression::map_t{result}}; } +auto Reverse(ExpressionPtr const& expr) -> ExpressionPtr { + if (not expr->IsList()) { + throw Evaluator::EvaluationError{fmt::format( + "reverse expects list but instead got: {}.", expr->ToString())}; + } + auto reverse_result = Expression::list_t(expr->List()); + std::reverse(reverse_result.begin(), reverse_result.end()); + return ExpressionPtr{reverse_result}; +} + auto NubRight(ExpressionPtr const& expr) -> ExpressionPtr { if (not expr->IsList()) { throw Evaluator::EvaluationError{fmt::format( @@ -957,6 +967,7 @@ auto const kBuiltInFunctions = {"keys", UnaryExpr(Keys)}, {"enumerate", UnaryExpr(Enumerate)}, {"set", UnaryExpr(Set)}, + {"reverse", UnaryExpr(Reverse)}, {"values", UnaryExpr(Values)}, {"lookup", LookupExpr}, {"empty_map", EmptyMapExpr}, diff --git a/test/buildtool/build_engine/expression/expression.test.cpp b/test/buildtool/build_engine/expression/expression.test.cpp index 7f3df7c5..242c0f4a 100644 --- a/test/buildtool/build_engine/expression/expression.test.cpp +++ b/test/buildtool/build_engine/expression/expression.test.cpp @@ -942,6 +942,21 @@ TEST_CASE("Expression Evaluation", "[expression]") { // NOLINT )"_json)); } + SECTION("reverse expression") { + auto expr = Expression::FromJson(R"( + { "type": "reverse" + , "$1": ["foo", "bar", "baz"] + } + )"_json); + REQUIRE(expr); + + auto result = expr.Evaluate(env, fcts); + REQUIRE(result); + CHECK(result == Expression::FromJson(R"( + ["baz", "bar", "foo"] + )"_json)); + } + SECTION("keys expression") { auto expr = Expression::FromJson(R"( { "type": "keys" |