fix(lexer): get_token => peek_token and pop_token

src/lexer/lexer.h

@@ -3,10 +3,19 @@
 
 #include <sys/types.h>
 
-/* @return: char*, the next token
+/*
+ * @brief: returns the next (newly allocated) token without consuming it.
+ *         if end of input is reached, returns EOF.
  *
  */
-char *get_token(void);
+char *peek_token(void);
+
+/*
+ * @brief: returns the next (newly allocated) token and consumes it.
+ *         if end of input is reached, returns EOF.
+ *
+ */
+char *pop_token(void);
 
 /*
  * @warning: NOT IMPLEMENTED.