1 files changed, 98 insertions, 0 deletions
diff --git a/prism/internal/static_literals.h b/prism/internal/static_literals.h
new file mode 100644
index 0000000000..d59002ac0a
--- /dev/null
+++ b/prism/internal/static_literals.h
@@ -0,0 +1,98 @@
+#ifndef PRISM_INTERNAL_STATIC_LITERALS_H
+#define PRISM_INTERNAL_STATIC_LITERALS_H
+
+#include "prism/ast.h"
+#include "prism/buffer.h"
+#include "prism/line_offset_list.h"
+
+/*
+ * An internal hash table for a set of nodes.
+ */
+typedef struct {
+    /* The array of nodes in the hash table. */
+    pm_node_t **nodes;
+
+    /* The size of the hash table. */
+    uint32_t size;
+
+    /* The space that has been allocated in the hash table. */
+    uint32_t capacity;
+} pm_node_hash_t;
+
+/*
+ * Certain sets of nodes (hash keys and when clauses) check for duplicate nodes
+ * to alert the user of potential issues. To do this, we keep a set of the nodes
+ * that have been seen so far, and compare whenever we find a new node.
+ *
+ * We bucket the nodes based on their type to minimize the number of comparisons
+ * that need to be performed.
+ */
+typedef struct {
+    /*
+     * This is the set of IntegerNode and SourceLineNode instances.
+     */
+    pm_node_hash_t integer_nodes;
+
+    /*
+     * This is the set of FloatNode instances.
+     */
+    pm_node_hash_t float_nodes;
+
+    /*
+     * This is the set of RationalNode and ImaginaryNode instances.
+     */
+    pm_node_hash_t number_nodes;
+
+    /*
+     * This is the set of StringNode and SourceFileNode instances.
+     */
+    pm_node_hash_t string_nodes;
+
+    /*
+     * This is the set of RegularExpressionNode instances.
+     */
+    pm_node_hash_t regexp_nodes;
+
+    /*
+     * This is the set of SymbolNode instances.
+     */
+    pm_node_hash_t symbol_nodes;
+
+    /*
+     * A pointer to the last TrueNode instance that was inserted, or NULL.
+     */
+    pm_node_t *true_node;
+
+    /*
+     * A pointer to the last FalseNode instance that was inserted, or NULL.
+     */
+    pm_node_t *false_node;
+
+    /*
+     * A pointer to the last NilNode instance that was inserted, or NULL.
+     */
+    pm_node_t *nil_node;
+
+    /*
+     * A pointer to the last SourceEncodingNode instance that was inserted, or
+     * NULL.
+     */
+    pm_node_t *source_encoding_node;
+} pm_static_literals_t;
+
+/*
+ * Add a node to the set of static literals.
+ */
+pm_node_t * pm_static_literals_add(const pm_line_offset_list_t *line_offsets, const uint8_t *start, int32_t start_line, pm_static_literals_t *literals, pm_node_t *node, bool replace);
+
+/*
+ * Free the internal memory associated with the given static literals set.
+ */
+void pm_static_literals_free(pm_static_literals_t *literals);
+
+/*
+ * Create a string-based representation of the given static literal.
+ */
+void pm_static_literal_inspect(pm_buffer_t *buffer, const pm_line_offset_list_t *line_offsets, const uint8_t *start, int32_t start_line, const char *encoding_name, const pm_node_t *node);
+
+#endif