OpenEuphoria

1. concept from Io language

• Posted by PL Feb 02, 2009
• 1086 views

Hello, I discovered euphoria sometime ago and find it interesting (specially, due to speed, co-routines, ...)

Concerning co-routines, I found a nice concept in language Io.

Let's give a small example:

V1 := O1 M1 

This line execute method "M1" of object O1 and put result in variable V1. Nothing special ...

V1 := O1 @M1 

Do the same but, - create a "future" (a special object) V1 - create a co-routine to execute the method asynchronously - when method is ended, V1 become an variable and get result of method

During execution of method, - the program can continue - If you try to access V1 (ex: V2 := V1 ...), program block untill M1 is finished. - You can of course check if M1 is finished

@M1 is indeed, sugar for @(M1) where @ is a function that execute a function in a co-routine.

You can for example, do sth like:

V1 := URL with("http://example1.com/") @fetch 
V2 := URL with("http://example2.com/") @fetch 
V3 := URL with("http://example3.com/") @fetch 
. . . 
do sth with V1 , V2 , V3 

They give a nice example: a minimal webserver where each request is executed in a co-routine:

WebRequest := Object clone do( 
    handleSocket := method(aSocket, 
        aSocket streamReadNextChunk 
        request := aSocket readBuffer betweenSeq("GET ", " HTTP") 
        f := File with(request)  
        if(f exists, f streamTo(aSocket), aSocket streamWrite("not found")) 
        aSocket close 
    ) 
) 
 
WebServer := Server clone do( 
    setPort(8000) 
    handleSocket := method(aSocket,  
        WebRequest clone **@**handleSocket(aSocket) 
    ) 
) 
 
WebServer start 

Could that be implemented in euphoria ?

3. Re: concept from Io language

• Posted by PL Feb 03, 2009
• 1038 views

I've seen that euphoria uses co-routine... so functionality is here. What I found interesting in Io was the simplicity: just put @ in front of a procedure/function/method to execute it in a co-routine.

NB: by the way, any blocking IO call in Io, generate automatiquely a yield. So, you put yield in your code ONLY for CPU intensive activity.