bshell: add ast node definitions

bshell/ast/int.c

@@ -0,0 +1,14 @@
+#include "../parse/token.h"
+#include "ast.h"
+
+static void to_string(const struct ast_node *node, fx_bstr *out)
+{
+	struct int_ast_node *i = (struct int_ast_node *)node;
+	fx_bstr_write_fmt(out, NULL, "%lld", i->n_value->tok_int);
+}
+
+struct ast_node_definition int_ast_node = {
+	.def_id = AST_INT,
+	.def_node_size = sizeof(struct int_ast_node),
+	.def_to_string = to_string,
+};