Training cost is always 1

[mattgodbolt]

Probably a hangover: https://github.com/mattgodbolt/xania/blob/main/src/act_move.cpp#L1067-L1212

Am refactoring that code now; so the cost is going to be made into ... a constant for now. CC @snellers in case you think costs need tweaking (easy to change if so!)

[mattgodbolt]

Sort of devalues the class's prime attribute a tiny bit? But probably not enough to worry about.

[snellers]

It's been a long time since I considered this one, so a few rambling thoughts...

My memory of how train worked may be hazy, but I always remember it costing 1 to train everything. My guess is that at some point, somebody was envisioning that eventually:

1. the stat that's the class's "primary" stat might cost nothing
2. or, the stats that aren't the class "primary" would cost more, 2 or 3 perhaps.
3. or a variation on that: certain things might cost more to train for players at a higher level, and/or make the cost of scaling certain stats like hp or mana scale up.
4. or maybe certain trainers would be more expensive than others based location, alignment or something like that.

Changing it to behave like 2 would impact how expert players would plan long term for their use of trains for the gain command. A long time ago we added the gain feature where you could blow trains to learn an out-of-class skill/spell group. This was pretty empowering, and gave players a longer term objective by making them think about how to optimize their spending, and incentivised getting +Wis items as early as possible to maximise trains gained each level too.

Doubling the (non-primary stat) training costs would probably put some gains out of reach, unless we also reworked the "trains gained at level time" calculation, or the costs of learning/gaining things, and those costs also apply at character creation time. So it'd have a ripple effect.

Option 3 would have less impact, I think. e.g. to discourage from pumping trains endlessly into the hp stat, the cost of it could increase slightly after you've done this a certain number of times. This would only make sense if there were players gaining an "unbalanced" advantage by min-maxing on hp, though. And of course right now there's no data to support that ;-)

Option 4 would only make sense if it was actually hard to get to a trainer, or where there was a reputation/faction system. I guess having an alignment penalty sort of makes sense.