1 files changed, 94 insertions, 0 deletions
diff --git a/third_party/nix/src/libexpr/primops/fromTOML.cc b/third_party/nix/src/libexpr/primops/fromTOML.cc
new file mode 100644
index 000000000000..e3d2a4940769
--- /dev/null
+++ b/third_party/nix/src/libexpr/primops/fromTOML.cc
@@ -0,0 +1,94 @@
+#include "cpptoml/cpptoml.h"
+#include "libexpr/eval-inline.hh"
+#include "libexpr/primops.hh"
+
+namespace nix {
+
+static void prim_fromTOML(EvalState& state, const Pos& pos, Value** args,
+                          Value& v) {
+  using namespace cpptoml;
+
+  auto toml = state.forceStringNoCtx(*args[0], pos);
+
+  std::istringstream tomlStream(toml);
+
+  std::function<void(Value&, std::shared_ptr<base>)> visit;
+
+  visit = [&](Value& v, std::shared_ptr<base> t) {
+    if (auto t2 = t->as_table()) {
+      size_t size = 0;
+      for (auto& i : *t2) {
+        (void)i;
+        size++;
+      }
+
+      state.mkAttrs(v, size);
+
+      for (auto& i : *t2) {
+        auto& v2 = *state.allocAttr(v, state.symbols.Create(i.first));
+
+        if (auto i2 = i.second->as_table_array()) {
+          size_t size2 = i2->get().size();
+          state.mkList(v2, size2);
+          for (size_t j = 0; j < size2; ++j) {
+            visit(*((*v2.list)[j] = state.allocValue()), i2->get()[j]);
+          }
+        } else {
+          visit(v2, i.second);
+        }
+      }
+    }
+
+    else if (auto t2 = t->as_array()) {
+      size_t size = t2->get().size();
+
+      state.mkList(v, size);
+
+      for (size_t i = 0; i < size; ++i) {
+        visit(*((*v.list)[i] = state.allocValue()), t2->get()[i]);
+      }
+    }
+
+    // Handle cases like 'a = [[{ a = true }]]', which IMHO should be
+    // parsed as a array containing an array containing a table,
+    // but instead are parsed as an array containing a table array
+    // containing a table.
+    else if (auto t2 = t->as_table_array()) {
+      size_t size = t2->get().size();
+
+      state.mkList(v, size);
+
+      for (size_t j = 0; j < size; ++j) {
+        visit(*((*v.list)[j] = state.allocValue()), t2->get()[j]);
+      }
+    }
+
+    else if (t->is_value()) {
+      if (auto val = t->as<int64_t>()) {
+        mkInt(v, val->get());
+      } else if (auto val = t->as<NixFloat>()) {
+        mkFloat(v, val->get());
+      } else if (auto val = t->as<bool>()) {
+        mkBool(v, val->get());
+      } else if (auto val = t->as<std::string>()) {
+        mkString(v, val->get());
+      } else {
+        throw EvalError("unsupported value type in TOML");
+      }
+    }
+
+    else {
+      abort();
+    }
+  };
+
+  try {
+    visit(v, parser(tomlStream).parse());
+  } catch (std::runtime_error& e) {
+    throw EvalError("while parsing a TOML string at %s: %s", pos, e.what());
+  }
+}
+
+static RegisterPrimOp r("fromTOML", 1, prim_fromTOML);
+
+}  // namespace nix