topic-42425

Posts: 1772

Joined: Thu Sep 05, 2019 05:32 AM

special Codeblock Syntax under Fivewin
Posted: Mon Nov 07, 2022 07:16 AM

hi,

i saw in some Code Syntax like this

 <||
    local oRect := oDlg:  GetCliRect  (  )
       oBar:  nWidth := oRect:  nWidth
       oLbx:  nWidth := oRect:  nWidth -   210
    RETURN   NIL
 >

where can i read "more" about this Syntax

in above Sample you need to pass oLbx as Parameter but how using that Syntax :?:

---

here a Sample how i pass Parameter to Codeblock

Code (fw): Select all Collapse

#include "FiveWin.ch"
PROCEDURE MAIN
LOCAL a := 1
LOCAL b := "a"
LOCAL cBlock, bBlock
   // you can per-build Codeblock as String
   cBlock := "{|a,b| DoTest(a,b)}"

   bBlock := &(cBlock)
   Eval(bBlock,a,b)

return

Code (fw): Select all Collapse

FUNCTION DoTest(a,b)
? a, VALTYPE(a)
? b, VALTYPE(b)
RETURN 0

as you can see i include Parameter between "|" (Pipe) Sign of Codeblock and pass them at EVAL()

greeting,

Jimmy

hmpaquito

Posts: 1515

Joined: Thu Oct 30, 2008 02:37 PM

Re: special Codeblock Syntax under Fivewin
Posted: Mon Nov 07, 2022 08:11 AM

Hi Mr. Jimmy,

They are named extended codeblocks
https://vivaclipper.wordpress.com/tag/codeblock/

This (extra) syntax too is correct for harbour:

Code (fw): Select all Collapse

{|| 
      a:= 1
      b:= 2
      c:= 3 
 }

Regards

hua

Posts: 1096

Joined: Fri Oct 28, 2005 02:27 AM

Re: special Codeblock Syntax under Fivewin
Posted: Mon Nov 07, 2022 10:02 AM

This is xHarbour style of extended codeblock

Code (fw): Select all Collapse

<|oLbx|
    local oRect := oDlg:  GetCliRect  (  )
       oBar:  nWidth := oRect:  nWidth
       oLbx:  nWidth := oRect:  nWidth -   210
    RETURN   NIL
 >

Harbour style

Code (fw): Select all Collapse

{|oLbx|
    local oRect := oDlg:  GetCliRect  (  )
       oBar:  nWidth := oRect:  nWidth
       oLbx:  nWidth := oRect:  nWidth -   210
    RETURN   NIL
 }

Just remember that extended codeblock must have RETURN

http://harbouradvisor.blogspot.com/2011/09/extended-codeblocks.html

FWH 11.08/FWH 19.12

BCC5.82/BCC7.3

xHarbour/Harbour

hmpaquito

Posts: 1515

Joined: Thu Oct 30, 2008 02:37 PM

Re: special Codeblock Syntax under Fivewin
Posted: Mon Nov 07, 2022 10:39 AM

Hi Hua,

Just remember that extended codeblock must have RETURN

It's not required return clause. Return clause it's neccessary only for return value

Code (fw): Select all Collapse

// Not neccessary return value. Only code. Implicity return value is NIL
x:= {||
         a:= 1
         b:= 2
         c:= 3 
      }

// Return value
y:= {||
         a:= 1
         b:= 2
         c:= 3 
         return b 
      }

Regards

Jimmy

Posts: 1772

Joined: Thu Sep 05, 2019 05:32 AM

Re: special Codeblock Syntax under Fivewin
Posted: Mon Nov 07, 2022 11:56 AM

hi,

thx all for Answer

hmpaquito wrote:It's not required return clause. Return clause it's neccessary only for return value

ah, that was what have confuse me

greeting,

Jimmy

cnavarro

Posts: 6755

Joined: Wed Feb 15, 2012 08:25 PM

Re: special Codeblock Syntax under Fivewin
Posted: Mon Nov 07, 2022 02:27 PM

Dear Jimmy
This syntax for codeblock, RETURN is required

Code (fw): Select all Collapse

   local bBlock
   bBlock  := <|| 
                  local a := 1
                  local b := 2
                  local c := 3
                  Return nil
               >

Cristobal Navarro

Hay dos tipos de personas: las que te hacen perder el tiempo y las que te hacen perder la noción del tiempo

El secreto de la felicidad no está en hacer lo que te gusta, sino en que te guste lo que haces

hmpaquito

Posts: 1515

Joined: Thu Oct 30, 2008 02:37 PM

Re: special Codeblock Syntax under Fivewin
Posted: Mon Nov 07, 2022 03:59 PM

Estimado Cristóbal,

La siguiente, sin return, es una sintaxis válida, que dará NIL como resultado de la operación Eval( bBlock )

Code (fw): Select all Collapse

 local bBlock
   bBlock  := <||
                  local a := 1
                  local b := 2
                  local c := 3
               >

Atte.

cnavarro

Posts: 6755

Joined: Wed Feb 15, 2012 08:25 PM

Re: special Codeblock Syntax under Fivewin
Posted: Mon Nov 07, 2022 08:40 PM

Estimadísimo Paquito
Yo es que soy un poco perfeccionista y como al no tener RETURN me da el siguiente mensaje ( tengo los warnings activados ) y como sabemos un codeblock es tratado internamente como si fuese una FUNCTION Anonymous

D:\FWH\FWHTEAM\SAMPLES\testtoast.prg(17) Warning W0007 Function '{||...}' does not end with RETURN statement
Compilation Errors
Link Error

Cristobal Navarro

Hay dos tipos de personas: las que te hacen perder el tiempo y las que te hacen perder la noción del tiempo

El secreto de la felicidad no está en hacer lo que te gusta, sino en que te guste lo que haces

hmpaquito

Posts: 1515

Joined: Thu Oct 30, 2008 02:37 PM

Re: special Codeblock Syntax under Fivewin
Posted: Mon Nov 07, 2022 09:06 PM

Hola Cristóbal,

Pues sí. Debe ser como tu dices: Los warning mandan y definen la sintaxis correcta.

Así en "stricto sensu" hay que poner un return en los extended codeblocks

Gracias por la aclaración

nageswaragunupudi

Posts: 10733

Joined: Sun Nov 19, 2006 05:22 AM

Re: special Codeblock Syntax under Fivewin
Posted: Tue Nov 08, 2022 02:27 AM

It's not required return clause. Return clause it's neccessary only for return value

"Return" is not required with xHarbour.
"Return" is required with Harbour.

So it is always safe to use return <someval> or return nil.
Our program should with both with Harbour and xHarbour.

It is always a good idea to keep our programs compatible with both Harbour and xHarbour and this is a must for us the FWteam.
It is safe to use this template:

Code (fw): Select all Collapse

< |params,..|
  // code
  return any
>

xHarbour:
Angular brackets is the right syntax for xHarbour and the return statement does not hurt xHarbour

Harbour:
Fivewin.ch translates the angular brackets ( < .. > ) to curly braces ( {..} ) when using Harbour and we also comply with the requirement of return statement.

Adantage of the extended codeblock syntax is that, we can use local variables and use commands like a normal program.

Regards

G. N. Rao.

Hyderabad, India

hmpaquito

Posts: 1515

Joined: Thu Oct 30, 2008 02:37 PM

Re: special Codeblock Syntax under Fivewin
Posted: Tue Nov 08, 2022 08:31 AM

Thank you very much Mr. Rao for your extense y comprensive explication

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