Fwd: Multidata Indicator (ie. McClellan Oscillator) EL Syntax

[SaulFFeld@xxxxxxx]

Mr Benjamin Blanco, Easy Language Specialist, from Omega Research replied to
my query. I am forwarding his answer to the list. I understand why his
prescription does clean up the code involved. 

Thank you to all that did, or had in mind to try to reply to me. Also thanks
to William Brower who the other day (Jan 30: "Unidentified subject"), had
addressed a whole family of EL syntaxl situations related to the problem here.

Thanks & congratulations to Omega Research & to Mr Blanco for the quality &
promptness of their reply; excellent!

  -Saul 

PS for Mr Blanco:  I will include my name, customer ID, block number and
telephone number on any future correspondence.
-----------------
Forwarded Message: 
Subj:	 Re:Multidata Indicator (ie. McClellan Oscillator) EL Syntax 
Date:	98-02-10 20:11:58 EST
From:	easylang@xxxxxxxxxxxxxxxxx
To:	SaulFFeld@xxxxxxx

980210BB

Mr. Feldman (FELDSAUL00),

    XAverage is a recursive function that requires an explicit price
parameter. 
Thus, the price parameter cannot be a variable or an array.  By the same
token,
if the price is using multiple data streams then the function must know
(explicitly) which data stream it will reference.

    You are able to work around this by making the XAverage price parameter an
input.  Since the input value is resolved first, the function is not confused
as
in the first paragraph.  For example:
Input: Price(Close of data1 - Close of data2);

Plot1(XAverage(Price,19) - XAverage(Price,39),"McClellan");

    Please include you name, customer ID, block number and telephone number on
any future correspondence.


Regards,

Benjamin Blanco
Easy Language Specialist
Omega Research Inc

____________________Reply Separator____________________
Subject:    Multidata Indicator (ie. McClellan Oscillator) EL Syntax Pro
Author: MIME:SaulFFeld@xxxxxxx
Date:       2/9/98 2:46 PM

Both TS 3.5 & 4 show the following EL code Syntax for the McClellan
Oscillator, applicable to stock market data: 

---------------------------------------------------------
Plot1(XAverage(Close of data1 - Close of data2,19) OF DATA1 - XAverage(Close
of data1 - Close of data2,39) OF DATA1,"McClellan");   [[1]]
--------------------------------------------------------

where using the Signal nomenclature, 
data1 could represent daily issues advancing, say as given by Symbol $ADV, and
data2 could represent daily issues declining, $DECL. 

The data for each Symbol can be placed in a Multidata Chart, 
on which the Indicator can be applied & it seems to work.

The syntax for the Exponential Average Function 
(page 270 of EL TS 4 Manual) is:
--------------------------------------------------
        Xaverage(Price,Length).      [[2]]
----------------------------------------------------

Since [[2]] is correct, & it is used in [[1]], 
[ where "Price" is replaced by "Close of data1 - Close of data2" ] 
why is the "OF DATA1" used TWICE in [[1]] instead of NOT AT ALL? 

I tried to delete those two "OF DATA1"s & the expression would not verify, 
it would highlight the "Xaverage" in the code, 
while giving following the error message:
GRAMMAR ERROR: Unresolvable Data Number.
If I add anything , like "OF DATA 35" & "OF DATA47" it does verify.

Nevertheless, the right values are being calculated by [[1]].

Is there some special undocumented Easy Language issue here because of
multidata streams?

May be I missed it, but does anyone know what is going on?

Whoever helps, thank you for it.

  -Saul
---------------------------------------------------------