Argument matching

[Lars Hansen]

In strict code ("use strict") the number of passed arguments must match
the number of expected arguments.  This has been agreed upon.

I would expect that if too few arguments are passed to a function with
a typed interface then you get a type error unless the missing parameter
has a type that includes "undefined" (ie no conversion takes place).
Signalling an error "because the function has a typed interface" is
a variant, I guess, but it seems like an orthogonal concern.

I would expect excess arguments to typed functions to be ignored
silently,
as they can be picked up by 'arguments' inside the function.

--lars

> -----Original Message-----
> From: es4-discuss-bounces at mozilla.org 
> [mailto:es4-discuss-bounces at mozilla.org] On Behalf Of Michael O'Brien
> Sent: 9. mai 2008 10:30
> To: es4-discuss Discuss
> Subject: Argument matching
> 
> What should ES4 do when there are too many or too few arguments?
> 
> Seems that the RI will apply different behavior depending on 
> whether the function arguments are typed or not. This is not 
> necessarily unexpected. I just want to nail down the rules as 
> the RI and AS3 behave differently in this regard.
> 
> Consider:
> 
> function fun(a, b) {
> 	print(a);
> 	print(b);
> }
> 
> Calling this with:
> 
> fun(1)			prints
> 	1
> 	undefined
> 
> fun(1,2,3,4)		prints
> 	1
> 	2
> 
> fun(1,undefined)
> 	1
> 	0	
> 
> both work without error.
> 
> But if either arg is typed:
> 
> function fun(a: int, b) {
> 	print(a);
> 	print(b);
> }
> 
> In this case, the following all get TypeErrors
> 
> fun(1)
> fun(1, undefined)
> fun(1,2,3,4)
> 
> Interestingly, ASC will coerce "undefined" to 0 if supplied 
> with the correct number of arguments and they are typed as ints.
> 
> What are the rules for ES4?
> 
> - If you type formal arguments, it seems the caller must 
> supply the correct number and type of actual parameters
> - If you don't type the formal arguments, you can supply too 
> few or too many arguments
> - Should undefined be coerced to 0 if the type is an integer?
> 
> Michael
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