This is more of a design opinion poll than a question.
I have a PC that is going to be learning a new skill during the course of a game, which means I will be making an action available later on. Let’s say the PC is learning how to dance.
What I am trying to decide is how to handle a player typing ‘dance’ just for fun prior to the player learning this skill. I’m not sure allowing the default message of “That’s not a verb I recognise” is the right approach because the parser will eventually recognize the verb and that may be misleading. On the other hand, a custom message may give away that ‘dance’ might be usable later on and that would give away part of a puzzle that the player should be able to figure out in a different way. Or maybe I shouldn’t worry about how the player gets to the solution as long as they do.
Anyone else ever run into this design problem and, if so, how did you address it?
You should definitely have a custom message from the start. If I tried a verb and got a standard parser error or an ineffective standard library response (“You jump on the spot”), I’d be unlikely to ever try that verb again. If I got stuck, gave up, and then found out later that I was supposed to use the verb all along, just at a different time - well, that’s the sort of thing that gets me calling down fire from heaven to punish the author’s mendacity.
The message should give a reason that the action is inappropriate at the moment without implying that it will never be appropriate. Unfortunately, you've never learned to dance might work, or something vague like This isn't the time or the place. If you’re worried that this will give something away, add similar messages (not identical ones - again, nothing that could be mistaken for a parser error or standard library response) for other commands that the player might try on a whim (SWIM, FLY, etc.).
A doubtfully relevant side note: like surprisingly many IF design problems, this was first addressed in Adventure. The method used there is quite interesting, though you might want to make the clues a teensy bit less obscure if you try something similar.
In Crowther’s unfinished original Adventure, BLAST yielded Blasting requires dynamite. This wasn’t the only response that referred perhaps deceptively to non-existent objects. DIG was another of Crowther’s: Digging without a shovel is quite impractical. The worst one of all was added by Woods in his completed version: when you try to feed the bird, It's not hungry (it's merely pinin' for the fjords). Besides, you have no bird seed., which is both the game’s funniest one-liner and its most misguided deceptive clue.
However, Woods also expanded Crowther’s brief comment on BLAST into an endgame puzzle. In Woods’ game, players were expected to vent their feelings occasionally, so there’s a response to FUCK: Watch it! The curious player, naturally, will then try other expletives to see if anything sticks. SHIT and DAMN, it turns out, are not recognized, but BLAST is, and that’s how the topic of dynamite is first brought up. I suspect that’s how players were meant to be clued in that BLAST is part of the parser’s limited vocabulary.
Then in the endgame, you come across a mysterious “rod with a rusty mark on the end,” a marked contrast to the previous rod with a rusty star, along with a hint (if you happen to find it) that reads: There is something strange about this place, such that one of the words I’ve always known now has a new effect. With some lateral thinking, the player might intuit that they now possess the required “dynamite” - or, more likely, they might simply try every verb in turn, but hopefully they at least remember that BLAST is a possibility.