wrong number of arguments (T3.1)

Authoring TADS
1

en_us.t defines a ‘drink’ verb, but it requires an object (‘drink wine’). The bare command ‘drink’, entered during a game, causes a run-time error – “wrong number of arguments”.

The line in en_us.t that the error pops up on is in the code for modify TAction, in the announceDefaultObject method. The line is:

local nm = obj.getAnnouncementDistinguisher().theName(obj);

What may or may not be relevant is that my own code adds a new DrinkFrom action and a new DrinkItFrom action. Somehow the parser is stumbling over this stuff. I don’t think it’s relevant, because when I replace the grammar for my new actions with gibberish and then type ‘drink’ in the game, the same error pops up.

How would I fix the code so as to get a standard “What do you want to drink?” query from the parser?

2

I can’t reproduce the problem. An empty game responds with “What do you want to drink?” when I enter “drink”.

3

If you could fire this up in the debugger, when you get to this point, see what obj.getAnnouncementDistinguisher() gives you. I’m guessing that’s the culprit - that object probably doesn’t have a theName() defined, thus the argument mismatch (undefined → implicitly zero arguments vs one argument fromthe caller).

(To look at this in the debugger, just run it in Workbench and trigger the error - the debugger will stop at the point where the error is triggered. Type ‘obj.getAnnouncementDistinguisher()’ into the watch window to evaluate that.)

4

I wish I was sure what “the debugger” is. I opened the Watch Expressions window and copied that string into the Expression field, but all I get for Value is “(error: wrong number of arguments”, and we knew that already.

Interestingly, if I start with the default introductory game, I don’t get this error in response to ‘drink’, but I do get it in response to ‘sit’.

In my own game, I get it in response to either ‘drink’ or ‘sit’ – and I’ve commented out all of my custom stuff relating to the command ‘drink’, leaving only the library code.

The one thing I did to the library code was hack en_us.t to add ‘sip’ as a fourth synonym. The code appears error-free:

VerbRule(Drink) ('drink' | 'quaff' | 'imbibe' | 'sip') dobjList : DrinkAction verbPhrase = 'drink/drinking (what)' ;

The library code for the ‘sit’ command is only a tiny bit more complex; it includes the bare command ‘sit’ with no object as SitAction. As that command does trigger the error, I can only guess that we’re seeing a library bug here.

I’m happy to help test it further, but I’m not really a tyro at using the debugging tools. Here’s the stack trace (or whatever it’s called) in the interpreter after I shift-F11 to get out of the error:

5

Here’s the top of the Call Stack (in Workbench) when I type ‘sit’ in a default game, triggering the run-time error:

6

Unrelated to the problem at hand, but I guess you’d like to know that you don’t need to hack the base files for this (it gets messy and causes problems when you upgrade to a new TADS version.) You can simply use a “modify” statement to change the syntax of existing verbs:

modify VerbRule(Drink) ('drink' | 'quaff' | 'imbibe' | 'sip') dobjList : // Empty - keeps the default action. ;

7

I could be totally wrong, because this stuff is well outside my comfort zone, but I think I see where the bug is, and how to fix it.

In en_us.t, the modify TAction block has the announceDefaultObject method. The second line in this method is:

local nm = obj.getAnnouncementDistinguisher().theName(obj);

But when I look up getAnnouncementDistinguisher() in the LRM, I see that it’s supposed to be called with an argument – (lst). This does seem to be a bug in en_us.t. And indeed, when I change the line to this:

local nm = obj.getAnnouncementDistinguisher([]).theName(obj);

…the run-time error vanishes with the morning dew. How sweet! Whether this fix may have side effects, I’ll leave for wise minds to say.

8

That is indeed the problem - that ‘modify TAction’ was some old code that I missed. Instead of an empty list, the actual argument should be gActor.scopeList():

local nm = obj.getAnnouncementDistinguisher(gActor.scopeList()).theName(obj);