Re: ES4 draft: array initializer expressions

[Olav Kjær]

I have a (perhaps stupid) question regarding the Array type syntax. What is
the use case for a type like:

[string, double, ...boolean]

I understand the utility of heterogeneous tuples of a fixed size, and of
homogeneous lists of variable size, but I don't really see when I would use
a hybrid like this. What am I missing?

regards
Olav Junker Kjær
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Re: ES4 draft: array initializer expressions

[Jeff Dyer]

'var' and 'const' need to be added to the lookahead set on
ExpressionStatement. That will take care of the ambiguity.

Jd


On 4/15/08 5:08 PM, Waldemar Horwat wrote:

> My comments:
> 
> 
> The grammar is ambiguous.
> 
> var [x, y] = expr;
> 
> is both an assignment expression statement and a destructuring variable
> binding statement.
> 
> 
> How does the "length" property work for structural type literals?  Is it
> always a fixture?
> 
> 
>> If the array initializer is prefixed by |const| or |var| then the array
>> properties created will be created as fixtures; if the prefix is |const|
>> those fixtures will additionally be read-only.
> 
> Am I to read this as stating that the length is also a constant if "const" is
> used?  It's a bit unclear.
> 
> 
> Waldemar
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Re: ES4 draft: array initializer expressions

[Waldemar Horwat]

My comments:


The grammar is ambiguous.

var [x, y] = expr;

is both an assignment expression statement and a destructuring variable binding 
statement.


How does the "length" property work for structural type literals?  Is it always 
a fixture?


> If the array initializer is prefixed by |const| or |var| then the array 
> properties created will be created as fixtures; if the prefix is |const| 
> those fixtures will additionally be read-only.

Am I to read this as stating that the length is also a constant if "const" is 
used?  It's a bit unclear.


Waldemar
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