irc: add flake reference support

Signed-off-by: NotAShelf <raf@notashelf.dev>
Change-Id: Icc96d297f02d3aad03b0373727d57f316a6a6964

src/irc/evaluator.cpp

@@ -69,6 +69,36 @@ struct Evaluator::Impl {
 
   explicit Impl(EvalState& s) : state(s) {}
 
+  static std::string escape_nix_string(std::string_view value) {
+    std::string escaped;
+    escaped.reserve(value.size());
+
+    for (char ch : value) {
+      switch (ch) {
+      case '\\':
+        escaped += "\\\\";
+        break;
+      case '"':
+        escaped += "\\\"";
+        break;
+      case '\n':
+        escaped += "\\n";
+        break;
+      case '\r':
+        escaped += "\\r";
+        break;
+      case '\t':
+        escaped += "\\t";
+        break;
+      default:
+        escaped.push_back(ch);
+        break;
+      }
+    }
+
+    return escaped;
+  }
+
   IREnvironment* make_env(IREnvironment* parent = nullptr) {
     auto env = new IREnvironment(parent);
     environments.push_back(std::unique_ptr<IREnvironment>(env));
@@ -612,6 +642,27 @@ struct Evaluator::Impl {
       } else {
         state.error<EvalError>("import argument must be a path or string").debugThrow();
       }
+    } else if (auto* n = node->get_if<BuiltinCallNode>()) {
+      std::vector<Value*> args;
+      args.reserve(n->args.size());
+
+      for (const auto& arg_node : n->args) {
+        Value* arg = state.allocValue();
+        eval_node(arg_node, *arg, env);
+        args.push_back(arg);
+      }
+
+      if (n->builtin_name == "getFlake") {
+        if (args.size() != 1) {
+          state.error<EvalError>("getFlake expects exactly one argument").debugThrow();
+        }
+        auto flake_ref = state.forceStringNoCtx(*args[0], noPos, "while evaluating getFlake");
+        std::string expr = "builtins.getFlake \"" + escape_nix_string(flake_ref) + "\"";
+        auto* parsed = state.parseExprFromString(expr, state.rootPath(CanonPath::root));
+        state.eval(parsed, v);
+      } else {
+        state.error<EvalError>("unsupported builtin call: %s", n->builtin_name).debugThrow();
+      }
     } else {
       v.mkNull();
     }

src/irc/ir_gen.cpp

@@ -226,6 +226,14 @@ struct IRGenerator::Impl {
       }
       return std::make_shared<Node>(ListNode(std::move(elements), n->line));
     }
+    if (auto* n = node.get_if<BuiltinCallNode>()) {
+      std::vector<std::shared_ptr<Node>> args;
+      args.reserve(n->args.size());
+      for (const auto& arg : n->args) {
+        args.push_back(convert(arg));
+      }
+      return std::make_shared<Node>(BuiltinCallNode(n->builtin_name, std::move(args), n->line));
+    }
     return std::make_shared<Node>(ConstNullNode{});
   }
 };

src/irc/main.cpp

@@ -1,22 +1,165 @@
 #include "ir_gen.h"
 #include "parser.h"
-#include "resolver.h"
 #include "serializer.h"
+#include <cctype>
 #include <cstring>
+#include <filesystem>
 #include <iostream>
+#include <stdexcept>
 #include <string>
 #include <vector>
 
 namespace nix_irc {
+namespace fs = std::filesystem;
 
 void print_usage(const char* prog) {
-  std::cout << "Usage: " << prog << " [options] <input.nix> [output.nixir]\n"
+  std::cout << "Usage: " << prog << " [options] <input.nix|flake#attr> [output.nixir]\n"
             << "\nOptions:\n"
             << "  -I <path>    Add search path for imports\n"
             << "  --no-imports Disable import resolution\n"
             << "  --help       Show this help\n";
 }
 
+static bool is_flake_reference(const std::string& input) {
+  return input.find('#') != std::string::npos;
+}
+
+static std::string sanitize_output_stem(const std::string& input) {
+  std::string stem;
+  stem.reserve(input.size());
+
+  for (char ch : input) {
+    if (std::isalnum(static_cast<unsigned char>(ch))) {
+      stem.push_back(ch);
+    } else if (stem.empty() || stem.back() != '-') {
+      stem.push_back('-');
+    }
+  }
+
+  while (!stem.empty() && stem.back() == '-') {
+    stem.pop_back();
+  }
+
+  return stem.empty() ? "bundle" : stem;
+}
+
+static std::string default_output_path_for(const std::string& input) {
+  if (!is_flake_reference(input)) {
+    return input + "ir";
+  }
+
+  return sanitize_output_stem(input) + ".nixir";
+}
+
+static std::string normalize_local_flake_path(const std::string& raw_path) {
+  fs::path path = raw_path.empty() ? fs::current_path() : fs::path(raw_path);
+  fs::path absolute = path.is_absolute() ? path : fs::absolute(path);
+  fs::path normalized = absolute.lexically_normal();
+
+  if (!fs::exists(normalized)) {
+    throw std::runtime_error("Flake path does not exist: " + normalized.string());
+  }
+
+  if (fs::is_directory(normalized) && !fs::exists(normalized / "flake.nix")) {
+    throw std::runtime_error("Flake directory does not contain flake.nix: " + normalized.string());
+  }
+
+  return normalized.string();
+}
+
+static std::string normalize_flake_ref_source(const std::string& ref) {
+  if (ref.empty()) {
+    return normalize_local_flake_path(".");
+  }
+
+  if (ref.rfind("path:", 0) == 0) {
+    return "path:" + normalize_local_flake_path(ref.substr(5));
+  }
+
+  if (ref[0] == '.' || ref[0] == '/') {
+    return normalize_local_flake_path(ref);
+  }
+
+  if (fs::exists(ref)) {
+    return normalize_local_flake_path(ref);
+  }
+
+  return ref;
+}
+
+static std::vector<std::string> parse_flake_attr_path(const std::string& raw_attr_path) {
+  if (raw_attr_path.empty()) {
+    throw std::runtime_error("Flake reference is missing an attribute path after '#'");
+  }
+
+  std::vector<std::string> segments;
+  std::string current;
+  bool in_quotes = false;
+  bool escaping = false;
+
+  for (char ch : raw_attr_path) {
+    if (escaping) {
+      current.push_back(ch);
+      escaping = false;
+      continue;
+    }
+
+    if (in_quotes) {
+      if (ch == '\\') {
+        escaping = true;
+      } else if (ch == '"') {
+        in_quotes = false;
+      } else {
+        current.push_back(ch);
+      }
+      continue;
+    }
+
+    if (ch == '"') {
+      in_quotes = true;
+    } else if (ch == '.') {
+      if (current.empty()) {
+        throw std::runtime_error("Flake attribute path contains an empty segment");
+      }
+      segments.push_back(current);
+      current.clear();
+    } else {
+      current.push_back(ch);
+    }
+  }
+
+  if (escaping || in_quotes) {
+    throw std::runtime_error("Unterminated quoted segment in flake attribute path");
+  }
+
+  if (current.empty()) {
+    throw std::runtime_error("Flake attribute path contains an empty segment");
+  }
+
+  segments.push_back(current);
+  return segments;
+}
+
+static std::shared_ptr<Node> build_flake_ref_ast(const std::string& input) {
+  size_t hash_pos = input.find('#');
+  if (hash_pos == std::string::npos) {
+    throw std::runtime_error("Not a flake reference: " + input);
+  }
+
+  std::string flake_source = normalize_flake_ref_source(input.substr(0, hash_pos));
+  auto attr_path = parse_flake_attr_path(input.substr(hash_pos + 1));
+
+  auto expr = std::make_shared<Node>(BuiltinCallNode(
+      "getFlake",
+      std::vector<std::shared_ptr<Node>>{std::make_shared<Node>(ConstStringNode(flake_source))}));
+
+  for (const auto& attr : attr_path) {
+    expr = std::make_shared<Node>(SelectNode(expr, std::make_shared<Node>(ConstStringNode(attr))));
+  }
+
+  return expr;
+}
+
 int run_compile(int argc, char** argv) {
   std::string input_file;
   std::string output_file;
@@ -57,20 +200,24 @@ int run_compile(int argc, char** argv) {
   }
 
   if (output_file.empty()) {
-    output_file = input_file + "ir";
+    output_file = default_output_path_for(input_file);
   }
 
   try {
     Parser parser;
-    Resolver resolver;
+    (void) search_paths;
+    (void) resolve_imports;
 
-    for (const auto& path : search_paths) {
-      resolver.add_search_path(path);
+    std::shared_ptr<Node> ast;
+
+    if (is_flake_reference(input_file)) {
+      std::cout << "Compiling flake reference: " << input_file << "\n";
+      ast = build_flake_ref_ast(input_file);
+    } else {
+      std::cout << "Parsing: " << input_file << "\n";
+      ast = parser.parse_file(input_file);
     }
 
-    std::cout << "Parsing: " << input_file << "\n";
-    auto ast = parser.parse_file(input_file);
-
     if (!ast) {
       std::cerr << "Error: Failed to parse input\n";
       return 1;

src/irc/serializer.cpp

@@ -78,6 +78,8 @@ struct Serializer::Impl {
       return NodeType::LAMBDA_PATTERN;
     if (node.holds<StringInterpolationNode>())
       return NodeType::STRING_INTERPOLATION;
+    if (node.holds<BuiltinCallNode>())
+      return NodeType::BUILTIN_CALL;
     return NodeType::ERROR;
   }
 
@@ -250,6 +252,13 @@ struct Serializer::Impl {
             write_node(*part.expr);
         }
       }
+    } else if (auto* n = node.get_if<BuiltinCallNode>()) {
+      write_string(n->builtin_name);
+      write_u32(n->args.size());
+      for (const auto& arg : n->args) {
+        if (arg)
+          write_node(*arg);
+      }
     }
   }
 };
@@ -366,6 +375,17 @@ struct Deserializer::Impl {
       std::string val = read_string();
       return std::make_shared<Node>(ConstLookupPathNode(val, line));
     }
+    case NodeType::BUILTIN_CALL: {
+      std::string builtin_name = read_string();
+      uint32_t num_args = read_u32();
+      std::vector<std::shared_ptr<Node>> args;
+      args.reserve(num_args);
+      for (uint32_t i = 0; i < num_args; i++) {
+        args.push_back(read_node());
+      }
+      return std::make_shared<Node>(
+          BuiltinCallNode(std::move(builtin_name), std::move(args), line));
+    }
     case NodeType::VAR: {
       uint32_t index = read_u32();
       return std::make_shared<Node>(VarNode(index, "", line));