diff options
Diffstat (limited to 'src/buildtool/build_engine/expression/evaluator.cpp')
| -rw-r--r-- | src/buildtool/build_engine/expression/evaluator.cpp | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/src/buildtool/build_engine/expression/evaluator.cpp b/src/buildtool/build_engine/expression/evaluator.cpp index e2b3819d..350afa4e 100644 --- a/src/buildtool/build_engine/expression/evaluator.cpp +++ b/src/buildtool/build_engine/expression/evaluator.cpp @@ -279,6 +279,35 @@ auto NubRight(ExpressionPtr const& expr) -> ExpressionPtr { return ExpressionPtr{reverse_result}; } +auto NubLeft(ExpressionPtr const& expr) -> ExpressionPtr { + if (not expr->IsList()) { + throw Evaluator::EvaluationError{fmt::format( + "nub_left expects list but instead got: {}.", expr->ToString())}; + } + if (not expr->IsCacheable()) { + throw Evaluator::EvaluationError{ + fmt::format("Implicit comparison by passing name-containing value " + "to nub_left: {}", + expr->ToString())}; + } + // short-cut evaluation for efficiency + if (expr->List().empty()) { + return expr; + } + auto const& list = expr->List(); + auto result = Expression::list_t{}; + result.reserve(list.size()); + auto seen = std::unordered_set<ExpressionPtr>{}; + seen.reserve(list.size()); + std::for_each(list.begin(), list.end(), [&](auto const& l) { + if (not seen.contains(l)) { + result.push_back(l); + seen.insert(l); + } + }); + return ExpressionPtr{result}; +} + auto Range(ExpressionPtr const& expr) -> ExpressionPtr { std::size_t len = 0; if (expr->IsNumber() && expr->Number() > 0.0) { @@ -1263,6 +1292,7 @@ auto const kBuiltInFunctions = {"+", UnaryExpr(Addition)}, {"*", UnaryExpr(Multiplication)}, {"nub_right", UnaryExpr(NubRight)}, + {"nub_left", UnaryExpr(NubLeft)}, {"range", UnaryExpr(Range)}, {"change_ending", ChangeEndingExpr}, {"basename", UnaryExpr(BaseName)}, |