diff --git a/src/include/parser.h b/src/include/parser.h
index 708f3c3..2ad30fd 100644
--- a/src/include/parser.h
+++ b/src/include/parser.h
@@ -3,17 +3,23 @@
 
 #include "token.h"
 #include "ast.h"
+#include "stack.h"
 
 typedef struct {
     size_t tokenc;      // Number of tokens in tokenv;
     Token* ctoken;      // The current token.
     Token** tokenv;     // Token vector.
     AST* ast;           // Abstract syntax tree.
+    Stack* ops;
+    Stack* nums;
 } Parser;
 
 Parser* parser_init(size_t tokenc, Token** tokenv);
 void parser_destroy(Parser* parser);
 
+// Increment parser->ctoken.
 void parser_inc(Parser* parser);
+// Step forward 1 token and add to stacks.
+void parser_step(Parser* parser);
 
 #endif
diff --git a/src/parser.c b/src/parser.c
index fa6b0e1..f61daf1 100644
--- a/src/parser.c
+++ b/src/parser.c
@@ -1,3 +1,4 @@
+#include "include/stack.h"
 #include "include/util.h"
 #include "include/parser.h"
 
@@ -8,6 +9,8 @@ Parser* parser_init(size_t tokenc, Token** tokenv) {
     parser->ctoken = *tokenv;
     parser->tokenv = tokenv;
     parser->ast = NULL;
+    parser->ops = stack_init();
+    parser->nums = stack_init();
 
     return parser;
 }
@@ -19,6 +22,9 @@ void parser_destroy(Parser* parser) {
     for (int i = 0; i < parser->tokenc; i++) token_destroy(parser->tokenv[i]);
 
     ast_destroy(parser->ast);
+
+    stack_destroy(parser->ops);
+    stack_destroy(parser->nums);
 }