Add parser for tokens->ast conversion

1 files changed, 84 insertions, 0 deletions

diff --git a/src/parser.h b/src/parser.h
new file mode 100755
index 0000000..ee5febe
--- /dev/null
+++ b/src/parser.h
@@ -0,0 +1,84 @@
+#ifndef BDL_PARSER_H
+#define BDL_PARSER_H
+
+#include "lexer.h"
+
+typedef enum ObjectType {
+    OBJ_TYPE_NIL,
+    OBJ_TYPE_TRUE,
+    OBJ_TYPE_FALSE,
+    OBJ_TYPE_FIXNUM,
+    OBJ_TYPE_SYMBOL,
+    OBJ_TYPE_STRING,
+    OBJ_TYPE_PAIR,
+} ObjectType;
+
+typedef struct Object {
+    ObjectType type;
+    union {
+        // OBJ_TYPE_FIXNUM
+        ssize_t fixnum;
+
+        // OBJ_TYPE_STRING
+        // OBJ_TYPE_SYMBOL
+        char *text;
+
+        // OBJ_TYPE_PAIR
+        struct {
+            struct Object *car;
+            struct Object *cdr;
+        };
+    };
+
+    size_t line;
+    size_t col;
+} Object;
+
+typedef struct Parser {
+    Token *tokens;
+    size_t current;
+} Parser;
+
+typedef Object* Root;
+
+// Mimics the functionality in the Scanner functions, but for tokens.
+Token next_token(Parser *parser);
+Token previous_token(Parser *parser);
+Token rewind_token(Parser *parser);
+Token peek_token(const Parser *parser);
+bool has_next_token(const Parser *parser);
+
+// Parsing operations.
+Object * parse_tree(Parser *parser, Errors *errors);
+Object * parse_symbol(Token tok);
+Object * parse_string(Token tok);
+Object * parse_bool(Token tok);
+Object * parse_fixnum(Token tok);
+Object * parse_list(Parser *parser, Errors *errors);
+Root * parse(Token *tokens, Errors *errors);
+
+// Object operations.
+void object_display(Object *obj);
+
+// Manage resources.
+Object * object_alloc(Token tok, ObjectType type);
+void object_free(Object *node);
+void free_roots(Root *roots);
+
+//
+// Helper macros.
+//
+
+// Type checking.
+#define IS_NIL(VAL)    ((VAL)->type == OBJ_TYPE_NIL)
+#define IS_TRUE(VAL)   ((VAL)->type != OBJ_TYPE_FALSE)
+#define IS_FALSE(VAL)  ((VAL)->type == OBJ_TYPE_FALSE)
+#define IS_FIXNUM(VAL) ((VAL)->type == OBJ_TYPE_FIXNUM)
+#define IS_STRING(VAL) ((VAL)->type == OBJ_TYPE_STRING)
+#define IS_SYMBOL(VAL) ((VAL)->type == OBJ_TYPE_SYMBOL)
+#define IS_PAIR(VAL)   ((VAL)->type == OBJ_TYPE_PAIR)
+
+// Debug.
+#define OBJ_PRINT(OBJ) object_display(OBJ); printf("\n");
+
+#endif // BDL_PARSER_H