Question Prerequisite Skills/Spells

Has anyone come up with a slick way to add in prereqs for spells and skills? I had thought about making a skilltree type setup where players would have to plan their characters out in advance instead of being able to learn everything their class can learn.

Would it be better to add extra fields to the spell/skill assignments in class.c or to add some type of function to guild spec proc in spec_procs.c?

I use a simple prereq system in my MUD but there are a variety of ways of accomplishing it depending on how complex of a system you are trying to achieve.

The simplest way would be to just add an extra field to the spell index and adjust the guildmaster proc to check to see if a skill has a prereq skill and if it's been mastered yet.

In my system I've also added a min_skill_level for the prereqs too which followed a similar design to what I mentioned above.