Expression closures - use-cases for shortcut lambda syntax (blocks)

Igor Bukanov igor at
Fri Mar 16 16:45:25 PDT 2007

On 16/03/07, Vassily Gavrilyak <gavrilyak at> wrote:
> Next about readability. My primary concern IS exactly readability, I never
> mind typing additional characters.
> But  I want to clearly show the intent in my code. I want to see word
> 'function' when it means exactly function.
> And I want to read 'block'  when it means block.
> so
> function someFunction(){               // this is a FUNCTION
>   using(File("hello". "r"), (\ file){     // this is a block that uses file.
>        process(file);
>   }) // file will be closed here.
> }

You do not need function closure here in ES4, use generators instead
(that already works in SpiderMonkey since Firefox 2.0):

for (file in autoFile("hello", "r")) {

where autoFile is a generator:

function autoFile(name, mode)
    File f = new File(name, mode)
    try {
        yield f;
    } finally {

That is, using idiom from C# is already available in JS with
generators so it can not be used as an argument for (\) expression.

Regards, Igor

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