Starting with the lexer, i'm starting to comprehend better what pratt parsing is and how to apply it. For now just declaring basic structure and functions

include/parser.h

@@ -0,0 +1,14 @@
+#include "lexer.h"
+
+typedef struct {
+    ASTNode *head;
+} AST;
+
+typedef enum {
+    PARSER_NUD, // Null Denotation
+    PARSER_LED, // Left Denotation
+} ParserState;
+
+size_t node_lbp(Operator op);
+size_t node_rbp(Operator op);
+AST parse(ASTNodeArray arr);