Make tree node handle names visible in context user fields

spec/propane_spec.rb

@@ -2113,6 +2113,38 @@ EOF
         end
       end
 
+      # Rust is excluded since a Rust tree node handle borrows the context, so
+      # storing one in a context field would make the context self-referential.
+      if %w[c cpp d].include?(language)
+        it "allows a tree node handle type in a context user field" do
+          write_grammar <<EOF
+tree;
+ptype int;
+context_user_fields <<
+    Item first_item;
+    int have_first;
+>>
+drop /\\s+/;
+token a /a/ << $$ = 7; >>
+Item -> a;
+Items -> ;
+Items -> Items Item <<
+    if (${context.have_first} == 0)
+    {
+        ${context.first_item} = $2;
+        ${context.have_first} = 1;
+    }
+>>
+Start -> Items;
+EOF
+          run_propane(language: language)
+          compile("spec/test_context_field_handle.#{language}", language: language)
+          results = run_test(language: language)
+          expect(results.stderr).to eq ""
+          expect(results.status).to eq 0
+        end
+      end
+
       if language == "rust"
         it "marks user code sections with their grammar file and line number" do
           write_grammar <<EOF

spec/test_context_field_handle.c

@@ -0,0 +1,39 @@
+#include "testparser.h"
+#include <assert.h>
+#include <string.h>
+#include "testutils.h"
+
+int main()
+{
+    char input[128];
+    size_t i;
+    p_context_t * context;
+    Token token;
+
+    /* Enough tokens that the tree node arena is reallocated during the parse. */
+    memset(input, 0, sizeof(input));
+    for (i = 0u; i < 40u; i++)
+    {
+        input[i] = 'a';
+    }
+
+    context = p_context_new((uint8_t const *)input, strlen(input));
+    assert_eq(P_SUCCESS, p_parse(context));
+
+    /* The handle was stored in a context user field during the parse, before
+     * the remaining nodes were created. It still refers to the same node. */
+    assert_eq(1u, context->have_first);
+    assert(p_node_valid(context->first_item));
+    token = p_Item_pToken1(context->first_item);
+    assert(p_node_valid(token));
+    assert_eq(TOKEN_a, p_Token_token(token));
+    assert_eq(7u, p_Token_pvalue(token));
+
+    /* The stored handle refers to the first Item, which starts at column 1. */
+    assert_eq(1u, p_node_position(context->first_item).row);
+    assert_eq(1u, p_node_position(context->first_item).col);
+
+    p_context_delete(context);
+
+    return 0;
+}

spec/test_context_field_handle.cpp

@@ -0,0 +1,36 @@
+#include "testparser.h"
+#include <cassert>
+#include <cstring>
+#include "testutils.h"
+
+int main()
+{
+    char input[128];
+
+    /* Enough tokens that the tree node arena is reallocated during the parse. */
+    memset(input, 0, sizeof(input));
+    for (size_t i = 0u; i < 40u; i++)
+    {
+        input[i] = 'a';
+    }
+
+    p_context_t * context = p_context_new((uint8_t const *)input, strlen(input));
+    assert_eq(P_SUCCESS, p_parse(context));
+
+    /* The handle was stored in a context user field during the parse, before
+     * the remaining nodes were created. It still refers to the same node. */
+    assert_eq(1u, context->have_first);
+    assert(context->first_item.valid());
+    Token token = context->first_item.pToken1();
+    assert(token.valid());
+    assert_eq(TOKEN_a, token.token());
+    assert_eq(7u, token.pvalue());
+
+    /* The stored handle refers to the first Item, which starts at column 1. */
+    assert_eq(1u, context->first_item.position().row);
+    assert_eq(1u, context->first_item.position().col);
+
+    p_context_delete(context);
+
+    return 0;
+}

spec/test_context_field_handle.d

@@ -0,0 +1,35 @@
+import testparser;
+import testutils;
+
+int main()
+{
+    return 0;
+}
+
+unittest
+{
+    /* Enough tokens that the tree node array is reallocated during the parse. */
+    string input;
+    foreach (i; 0 .. 40)
+    {
+        input ~= "a";
+    }
+
+    p_context_t * context = p_context_new(input);
+    assert_eq(P_SUCCESS, p_parse(context));
+
+    /* The handle was stored in a context user field during the parse, before
+     * the remaining nodes were created. It still refers to the same node. */
+    assert_eq(1, context.have_first);
+    assert(context.first_item.valid);
+    Token token = context.first_item.pToken1;
+    assert(token.valid);
+    assert_eq(TOKEN_a, token.token);
+    assert_eq(7, token.pvalue);
+
+    /* The stored handle refers to the first Item, which starts at column 1. */
+    assert_eq(1u, context.first_item.position.row);
+    assert_eq(1u, context.first_item.position.col);
+
+    p_context_delete(context);
+}