Variable length list of parameters in oScript

Hi,In oScript, there are a couple of functions such as CAPI.Exec, Str.Format, which have a variable length list of optional parameters.We sometimes need to wrap these functions up in our own functions. However, I don't really know how to pass through these optional parameters. For example, I would like to write a function like this (pseudo code)function MyFunc( arg1, arg2, optionalargs = ... )...CAPI.Exec(connect, statement, optionalargs)...endSo could anyone explain to me- How to set up a function with variable length optional parameters like MyFunc above.- How to pass those parameters through (say, move them up the stack).I even tried thisList customparams = {a1, a2, a3}CAPI.Exec( connect, statement, @customparams )But Builder rejected to compile that.Thanks,Thanh

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Hans Stoop

Message from Hans Stoop <hstoop@opentext.com> via eLink

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One way I see you can do this is by having the optional parameters passed in a parameters as a list. And then based on the length of the list call the functiond with the right number of parameters.

The othe roption is to specify a large list of optional parameters to your function and give them the default value of UNDEFINED.

By determining the last non-UNDEFINED value you know how many parameters are passed and you can make the correct call depending on the number of parameters.

Both these methods has the limitations that there is a predefined maximum to the number of parameters.

To be really flexible you can use the method to pass the parameters in the list and then generate the code with the correct number fo parameters and execute that function.

Hans

________________________________________________________________________________________________________
Hans Stoop
Senior Consultant, Global Services

Open Text
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From: eLink Discussion: Development Discussion [mailto:development@elinkkc.opentext.com]
Sent: Friday, September 25, 2009 12:18 PM
To: eLink Recipient
Subject: Variable length list of parameters in oScript

Variable length list of parameters in oScript

Posted by thanh.ho@mottmac.com (Ho, Thanh) on 2009/09/25 06:13

Hi,

In oScript, there are a couple of functions such as CAPI.Exec, Str.Format, which have a variable length list of optional parameters.

We sometimes need to wrap these functions up in our own functions. However, I don't really know how to pass through these optional parameters. For example, I would like to write a function like this (pseudo code)

function MyFunc( arg1, arg2, optionalargs = ... )
...
CAPI.Exec(connect, statement, optionalargs)
...

end

So could anyone explain to me
- How to set up a function with variable length optional parameters like MyFunc above.
- How to pass those parameters through (say, move them up the stack).

I even tried this

List customparams = {a1, a2, a3}
CAPI.Exec( connect, statement, @customparams )
But Builder rejected to compile that.

Thanks,
Thanh

Thanh_Ho

Thanks Hans,I did think about these solutions but the tricky bit is that each length of the list would require a dedicated function call. For example I ought to write (pseudo code)...if( length == 2 ) then capi.exec( c, s, arg1, arg2 )else if (length == 3) thencapi.exec( c, s, arg1, arg2, arg3 )...endYou mention about generating the code and run that code at run-time. Is that possible? Could you explain it to me with more details?Thanks,Thanh

Hans Stoop

Message from Hans Stoop <hstoop@opentext.com> via eLink

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Maybe this coding example will help. It probably won't compile, but will give you an impression how to do it.

funcScript = Str.Format('Function Dynamic sqlExec(CAPICONNECT cConnect, String s, List Parms)%1', Str.EOL() )
funcScript += Str.Format('return CAPI.Exec( cConnect, s, ' )
sep1 = SQLSpec.sep[1]
sep2 = ''
i = 1
for fieldSpec in keyFieldSpecs
  values[i] = keyValues.(fieldSpec.column)

  sqlString += Str.Format( SQLSpec.format, i, sep1, fieldSpec.column )
  funcScript += Str.Format( '%2Parms[%1]', i, sep2 )
  i += 1
  sep1 = SQLSpec.sep[2]
  sep2 = ', '
end
sqlString += sqlSpec.commandEnd
funcScript += Str.Format( ')%1end', Str.EOL())
.sqlExec = Compiler.MakeScript(funcScript)
if IsError(.sqlExec) || Type(.sqlExec) != ScriptType
  ok = false
  retVal.message = Str.Format([MY_ERROR.InternalCompileErrorUnableToCompileScript12], Str.EOL(), funcScript)
end

//Execute the script

if ok
  res = .sqlExec(cConnect, sqlString, values)
  if IsNotError(res)
   retVal.recs = res
   end
  end
end

________________________________________________________________________________________________________
Hans Stoop
Senior Consultant, Global Services

From: eLink Discussion: Development Discussion [mailto:development@elinkkc.opentext.com]
Sent: Friday, September 25, 2009 1:24 PM
To: eLink Recipient
Subject: Thanks Hans,

Thanks Hans,		Posted by thanh.ho@mottmac.com (Ho, Thanh) on 2009/09/25 07:20
In reply to: RE Variable length list of parameters in oScript		Posted by hstoop (Stoop, Hans) on 2009/09/25 06:32

Thanks Hans,

I did think about these solutions but the tricky bit is that each length of the list would require a dedicated function call. For example I ought to write (pseudo code)

...
if( length == 2 ) then
capi.exec( c, s, arg1, arg2 )
else if (length == 3) then
capi.exec( c, s, arg1, arg2, arg3 )
...
end

You mention about generating the code and run that code at run-time. Is that possible? Could you explain it to me with more details?

Thanks,
Thanh

Thanh_Ho

Thanks Hans, I'll try.

John W. Simon, Jr.

Thanh Ho, would you mind posting your findings. I am curious to know what you learned during this exercise...

Thanh_Ho

Sorry John. A bit late reply.The idea Hans gave is that he created a string containing the code, which was a script. Then, he compiled that code at run time. Since he did it at run time, he was be able to progammatically create the script code. Then, he ran that compiled code. The trouble with oScript is that you need to compile the code (although it's a script language), you can't run it without compiling. It seems to be to much work for us so I had to choose the other way round. Below is a modified version of our codefunction Dynamic _FunctionName(LLconnect, sqlStatement, otherParams, sqlParams = Undefined)......if( IsUndefined( sqlParams ))......sqlParams = {}...end...if( type(sqlParams) != listType )......sqlParams = { sqlParams }...end......Dynamic execResult......switch( Length( sqlParams ) )......case 0.........execResult = CAPI.Exec( LLconnect, sqlStatement)......end......case 1.........execResult = CAPI.Exec( LLconnect, sqlStatement, sqlParams[1] )......end......case 2.........execResult = CAPI.Exec( LLconnect, sqlStatement, sqlParams[1], sqlParams[2])......end......case 3.........execResult = CAPI.Exec( LLconnect, sqlStatement, sqlParams[1], sqlParams[2], sqlParams[3])......end......case 4.........execResult = CAPI.Exec( LLconnect, sqlStatement, sqlParams[1], sqlParams[2], sqlParams[3], sqlParams[4] )......end......case 5.........execResult = CAPI.Exec( LLconnect, sqlStatement, sqlParams[1], sqlParams[2], sqlParams[3], sqlParams[4], sqlParams[5])......end......case 6.........execResult = CAPI.Exec( LLconnect, sqlStatement, sqlParams[1], sqlParams[2], sqlParams[3], sqlParams[4], sqlParams[5], sqlParams[6] )......end......default.........return errorMsg......end...endblah blahendThen you can call._FunctionName(connect, sql, otherParams)._FunctionName(connect, sql, otherParams, sqlParam1)._FunctionName(connect, sql, otherParams, {sqlParam1, sqlParam2} )(Note the list of params)In C, moving param list up the stack used to be quite a norm due to structure of call stack, though no longer be popular. Sadly, oScript is a bit higher level at this and the use of variable length param list makes stacking difficult. I would be much happier if CAPI.Exec required a list type.

Kyle_Swidrovich

Message from Kyle Swidrovich <kswidrov@opentext.com> via eLink

eLink

I believe CAPI.ExecN does accept a list,in a sense.

Here is a snippet from$LLIAPI.CacheUtil._Write:

// initialize the recarray

RecArray ra =RecArray.Create( { 'ObjectID', 'SegmentID', 'SegmentBlob', 'ObjectDate' } )

// create array of values toinsert

for i = 1 to objectSize bysegmentSize

RecArray.AddRecord(ra, { objectID, segmentID += 1, objectBlob[ i : i + segmentSize - 1 ],objectDate } )

end

// insert the values

s = 'insert into LLCachevalues (:A1,:A2,:A3,:A4)'

r = CAPI.ExecN( connection, s,ra )

Although this allows for multiple rows ofvalues, one could simply have a single record with X number of columns, eachcontaining a bind variable value.

_________________________________________

Kyle Swidrovich

Principal Search / SDK Product Specialist
Livelink Escalations Support Team
Open Text Corporation

275 Frank Tompa Dr.
Waterloo, ON, CANADA

Phone : +1-800-540-7292
Online: http://support.opentext.com
_________________________________________

From: eLinkDiscussion: Development Discussion [mailto:development@elinkkc.opentext.com]
Sent: Tuesday, October 06, 200911:02 AM
To: eLink Recipient
Subject: Sorry John. A bit latereply.

Sorry John. A bit late reply.		Posted by thanh.ho@mottmac.com (Ho, Thanh) on 2009/10/06 10:58
In reply to: re - post results		Posted by conocoadmin (Simon, John) on 2009/09/28 13:22

Sorry John. A bit late reply.

The idea Hans gave is that he created a string containing the code, which was a script. Then, he compiled that code at run time. Since he did it at run time, he was be able to progammatically create the script code. Then, he ran that compiled code. The trouble with oScript is that you need to compile the code (although it's a script language), you can't run it without compiling. It seems to be to much work for us so I had to choose the other way round. Below is a modified version of our code
function Dynamic _FunctionName(LLconnect, sqlStatement, otherParams, sqlParams = Undefined)
...
...if( IsUndefined( sqlParams ))
......sqlParams = {}
...end
...if( type(sqlParams) != listType )
......sqlParams = { sqlParams }
...end
...
...Dynamic execResult
...
...switch( Length( sqlParams ) )
......case 0
.........execResult = CAPI.Exec( LLconnect, sqlStatement)
......end
......case 1
.........execResult = CAPI.Exec( LLconnect, sqlStatement, sqlParams[1] )
......end
......case 2
.........execResult = CAPI.Exec( LLconnect, sqlStatement, sqlParams[1], sqlParams[2])
......end
......case 3
.........execResult = CAPI.Exec( LLconnect, sqlStatement, sqlParams[1], sqlParams[2], sqlParams[3])
......end
......case 4
.........execResult = CAPI.Exec( LLconnect, sqlStatement, sqlParams[1], sqlParams[2], sqlParams[3], sqlParams[4] )
......end
......case 5
.........execResult = CAPI.Exec( LLconnect, sqlStatement, sqlParams[1], sqlParams[2], sqlParams[3], sqlParams[4], sqlParams[5])
......end
......case 6
.........execResult = CAPI.Exec( LLconnect, sqlStatement, sqlParams[1], sqlParams[2], sqlParams[3], sqlParams[4], sqlParams[5], sqlParams[6] )
......end
......default
.........return errorMsg
......end
...end

blah blah

end

Then you can call
._FunctionName(connect, sql, otherParams)
._FunctionName(connect, sql, otherParams, sqlParam1)
._FunctionName(connect, sql, otherParams, {sqlParam1, sqlParam2} )
(Note the list of params)

In C, moving param list up the stack used to be quite a norm due to structure of call stack, though no longer be popular. Sadly, oScript is a bit higher level at this and the use of variable length param list makes stacking difficult. I would be much happier if CAPI.Exec required a list type.

John W. Simon, Jr.

Thanks for posting your solution.