node_context::lookup returns optional instead of (unsigned) -1

dsharlet · Jan 1, 2024 · eec082e · eec082e
1 parent 592e917
commit eec082e
Show file tree

Hide file tree

Showing 3 changed files with 13 additions and 12 deletions.
diff --git a/src/expr.cc b/src/expr.cc
@@ -13,26 +13,26 @@ std::string node_context::name(symbol_id i) const {
 }
 
 symbol_id node_context::insert(const std::string& name) {
-  symbol_id id = lookup(name);
-  if (id == -1) {
+  std::optional<symbol_id> id = lookup(name);
+  if (!id) {
     id = id_to_name.size();
     id_to_name.push_back(name);
   }
-  return id;
+  return *id;
 }
 symbol_id node_context::insert_unique(const std::string& prefix) {
   symbol_id id = id_to_name.size();
   id_to_name.push_back(prefix + std::to_string(id));
   return id;
 }
-symbol_id node_context::lookup(const std::string& name) const {
+std::optional<symbol_id> node_context::lookup(const std::string& name) const {
   // TODO: At some point we might need a better data structure than doing this linear search.
   for (symbol_id i = 0; i < id_to_name.size(); ++i) {
     if (id_to_name[i] == name) {
       return i;
     }
   }
-  return -1;
+  return {};
 }
 
 template <typename T>

diff --git a/src/expr.h b/src/expr.h
@@ -11,6 +11,7 @@
 #include <span>
 #include <string>
 #include <vector>
+#include <optional>
 
 namespace slinky {
 
@@ -28,7 +29,7 @@ class node_context {
   // Get or insert a new symbol_id for a name.
   symbol_id insert(const std::string& name);
   symbol_id insert_unique(const std::string& prefix = "_");
-  symbol_id lookup(const std::string& name) const;
+  std::optional<symbol_id> lookup(const std::string& name) const;
 };
 
 enum class node_type {

diff --git a/test/evaluate.cc b/test/evaluate.cc
@@ -9,10 +9,10 @@ using namespace slinky;
 
 TEST(evaluate_arithmetic) {
   node_context ctx;
-  expr x = make_variable(ctx, "x");
+  var x(ctx, "x");
 
   eval_context context;
-  context[ctx.lookup("x")] = 4;
+  context[x] = 4;
 
   ASSERT_EQ(evaluate(x + 5, context), 9);
   ASSERT_EQ(evaluate(x - 3, context), 1);
@@ -37,7 +37,7 @@ TEST(evaluate_arithmetic) {
 
 TEST(evaluate_call) {
   node_context ctx;
-  expr x = make_variable(ctx, "x");
+  var x(ctx, "x");
   std::vector<index_t> calls;
   stmt c = call_func::make(
       [&](std::span<const index_t> scalars, std::span<raw_buffer*> buffers) -> index_t {
@@ -47,7 +47,7 @@ TEST(evaluate_call) {
       {x}, {}, nullptr);
 
   eval_context context;
-  context[ctx.lookup("x")] = 2;
+  context[x] = 2;
 
   int result = evaluate(c, context);
   ASSERT_EQ(result, 0);
@@ -57,7 +57,7 @@ TEST(evaluate_call) {
 
 TEST(evaluate_loop) {
   node_context ctx;
-  expr x = make_variable(ctx, "x");
+  var x(ctx, "x");
   std::vector<index_t> calls;
   stmt c = call_func::make(
       [&](std::span<const index_t> scalars, std::span<raw_buffer*> buffers) -> index_t {
@@ -66,7 +66,7 @@ TEST(evaluate_loop) {
       },
       {x}, {}, nullptr);
 
-  stmt l = loop::make(ctx.lookup("x"), range(2, 12), c);
+  stmt l = loop::make(x.name(), range(2, 12), c);
 
   int result = evaluate(l);
   ASSERT_EQ(result, 0);