cli: Add AST pretty-printing option (--ast-dump)

Parsing can be a complex process, and it's not always easy to get a
clear picture of what's happening with the AST.  This commit adds a new
feature to the CLI that allows us to pretty-print the AST (outputs to
stdout), making it easier to visualize the tree structure and understand
how the parser is working.

The new --ast-dump option generates a human-readable representation of
the AST, including node types, values, and child relationships. This
information can be invaluable for debugging and understanding the
parser's behavior.

Signed-off-by: Johnny Richard <johnny@johnnyrichard.com>
Reviewed-by: Carlos Maniero <carlos@maniero.me>

1 files changed, 41 insertions, 0 deletions

diff --git a/src/ast_pretty_printer.h b/src/ast_pretty_printer.h
new file mode 100644
index 0000000..d7e36b7
--- /dev/null
+++ b/src/ast_pretty_printer.h
@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2023 Johnny Richard
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+#ifndef AST_PRETTY_PRINTER_H
+#define AST_PRETTY_PRINTER_H
+
+#include "ast.h"
+
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+
+typedef struct ast_pretty_printer_t
+{
+  uint64_t indentation_fmt;
+  uint64_t indentation_lst_children;
+  uint32_t indentation_level;
+  bool last_children;
+  FILE *stream;
+} ast_pretty_printer_t;
+
+void
+ast_pretty_printer_init(ast_pretty_printer_t *printer, FILE *stream);
+
+void
+ast_pretty_printer_print_ast(ast_pretty_printer_t *printer, ast_node_t *ast);
+
+#endif /* AST_PRETTY_PRINTER_H */