<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:x="urn:schemas-microsoft-com:office:excel" xmlns:p="urn:schemas-microsoft-com:office:powerpoint" xmlns:a="urn:schemas-microsoft-com:office:access" xmlns:dt="uuid:C2F41010-65B3-11d1-A29F-00AA00C14882" xmlns:s="uuid:BDC6E3F0-6DA3-11d1-A2A3-00AA00C14882" xmlns:rs="urn:schemas-microsoft-com:rowset" xmlns:z="#RowsetSchema" xmlns:b="urn:schemas-microsoft-com:office:publisher" xmlns:ss="urn:schemas-microsoft-com:office:spreadsheet" xmlns:c="urn:schemas-microsoft-com:office:component:spreadsheet" xmlns:odc="urn:schemas-microsoft-com:office:odc" xmlns:oa="urn:schemas-microsoft-com:office:activation" xmlns:html="http://www.w3.org/TR/REC-html40" xmlns:q="http://schemas.xmlsoap.org/soap/envelope/" xmlns:rtc="http://microsoft.com/officenet/conferencing" xmlns:D="DAV:" xmlns:Repl="http://schemas.microsoft.com/repl/" xmlns:mt="http://schemas.microsoft.com/sharepoint/soap/meetings/" xmlns:x2="http://schemas.microsoft.com/office/excel/2003/xml" xmlns:ppda="http://www.passport.com/NameSpace.xsd" xmlns:ois="http://schemas.microsoft.com/sharepoint/soap/ois/" xmlns:dir="http://schemas.microsoft.com/sharepoint/soap/directory/" xmlns:ds="http://www.w3.org/2000/09/xmldsig#" xmlns:dsp="http://schemas.microsoft.com/sharepoint/dsp" xmlns:udc="http://schemas.microsoft.com/data/udc" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:sub="http://schemas.microsoft.com/sharepoint/soap/2002/1/alerts/" xmlns:ec="http://www.w3.org/2001/04/xmlenc#" xmlns:sp="http://schemas.microsoft.com/sharepoint/" xmlns:sps="http://schemas.microsoft.com/sharepoint/soap/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:udcs="http://schemas.microsoft.com/data/udc/soap" xmlns:udcxf="http://schemas.microsoft.com/data/udc/xmlfile" xmlns:udcp2p="http://schemas.microsoft.com/data/udc/parttopart" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns:st="" xmlns="http://www.w3.org/TR/REC-html40">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<meta name="Generator" content="Microsoft Word 12 (filtered medium)">
<!--[if !mso]>
<style>
v\:* {behavior:url(#default#VML);}
o\:* {behavior:url(#default#VML);}
w\:* {behavior:url(#default#VML);}
.shape {behavior:url(#default#VML);}
</style>
<![endif]--><style>
<!--
/* Font Definitions */
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
@font-face
{font-family:Tahoma;
panose-1:2 11 6 4 3 5 4 4 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0cm;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Times New Roman","serif";}
span.emailstyle17
{mso-style-name:emailstyle17;}
span.emailstyle171
{mso-style-name:emailstyle171;
font-family:"Calibri","sans-serif";
color:#1F497D;}
span.EmailStyle19
{mso-style-type:personal-reply;
font-family:"Calibri","sans-serif";
color:#1F497D;}
.MsoChpDefault
{mso-style-type:export-only;}
@page Section1
{size:612.0pt 792.0pt;
margin:72.0pt 72.0pt 72.0pt 72.0pt;}
div.Section1
{page:Section1;}
-->
</style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]-->
</head>
<body lang="EN-GB" link="#000000" vlink="#000000">
<div class="Section1">
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D">You may be better asking on the MVEL mailing list for this. My best guess is that it is a combination from the compiler knowing that the result of the + is
being assigned to a string and because all your variables are strings it uses string operations. You’d have to check but I’d also imagine that the expression string1 * string2 probably compiles to something like (String)( (number)string1 * (number)string2
) ie while within the calculation the strings are converted to numbers the result may still be a string.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D">Either way I think the expression is vary ambiguous and putting casts in there don’t make it messy they make it obvious what exactly your wish is.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D">Thomas<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D"><o:p> </o:p></span></p>
<div style="border:none;border-left:solid blue 1.5pt;padding:0cm 0cm 0cm 4.0pt">
<div>
<div style="border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm 0cm 0cm">
<p class="MsoNormal"><b><span lang="EN-US" style="font-size:10.0pt;font-family:
"Tahoma","sans-serif"">From:</span></b><span lang="EN-US" style="font-size:10.0pt;
font-family:"Tahoma","sans-serif""> rules-users-bounces@lists.jboss.org [mailto:rules-users-bounces@lists.jboss.org]
<b>On Behalf Of </b>Kinshuk Adhikary<br>
<b>Sent:</b> 21 December 2009 10:12<br>
<b>To:</b> Rules Users List<br>
<b>Subject:</b> Re: [rules-users] Re-sending : Unexpected MVEL plus operatorbehavior(string-to-double), in consequence block<o:p></o:p></span></p>
</div>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
<table class="MsoNormalTable" border="0" cellspacing="0" cellpadding="0">
<tbody>
<tr>
<td valign="top" style="padding:0cm 0cm 0cm 0cm">
<p class="MsoNormal">Hi,<br>
<br>
It does work if cast, but the logic of the + operator is what I am trying to get at.<br>
<br>
1. Having converted them (as you said, multiplication will try to convert and it does), they ought to be now numbers. So the + operator should not concatenate, should just add the numbers.<br>
<br>
Actually leaving messy casts all around is what is "not nice" about it.<br>
<br>
Regards and thanks<br>
<br>
Kinshuk<br>
<br>
--- On <b>Mon, 12/21/09, Swindells, Thomas <i><TSwindells@nds.com></i></b> wrote:<o:p></o:p></p>
<p class="MsoNormal" style="margin-bottom:12.0pt"><br>
From: Swindells, Thomas <TSwindells@nds.com><br>
Subject: Re: [rules-users] Re-sending : Unexpected MVEL plus operator behavior(string-to-double), in consequence block<br>
To: "Rules Users List" <rules-users@lists.jboss.org><br>
Date: Monday, December 21, 2009, 2:54 PM<o:p></o:p></p>
<div id="yiv618864867">
<div>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;color:#1F497D">My gut instinct would say that this is possibly correct.</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;color:#1F497D">I’ve not looked at the mvel code but if all your types are strings then it makes sense for it to pick the most type specific operator
first. Multiplication only works on numbers so it attempts to convert them but the + operator is defined on strings and therefore is a closer match for strings as you are assigning the result to a string.</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;color:#1F497D">I haven’t tried it but you could liberally sprinkling in brackets and type casts to get what you want, eg:</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;margin-bottom:12.0pt">t.out = (double)(t.in2*t.in3) + (double)(t.in3*t.in4) + (double)(t.in2*t.in4);<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;color:#1F497D">Thomas</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;color:#1F497D"> </span><o:p></o:p></p>
<div style="border:none;border-left:solid windowtext 1.5pt;padding:0cm 0cm 0cm 4.0pt;
border-color:-moz-use-text-color -moz-use-text-color -moz-use-text-color blue">
<div>
<div style="border:none;border-top:solid windowtext 1.0pt;padding:3.0pt 0cm 0cm 0cm;
border-color:-moz-use-text-color -moz-use-text-color">
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><b><span lang="EN-US" style="font-size:10.0pt">From:</span></b><span lang="EN-US" style="font-size:10.0pt"> rules-users-bounces@lists.jboss.org [mailto:rules-users-bounces@lists.jboss.org]
<b>On Behalf Of </b>Kinshuk Adhikary<br>
<b>Sent:</b> 21 December 2009 02:48<br>
<b>To:</b> rules-users@lists.jboss.org<br>
<b>Subject:</b> [rules-users] Re-sending : Unexpected MVEL plus operator behavior(string-to-double), in consequence block</span><o:p></o:p></p>
</div>
</div>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
<table class="MsoNormalTable" border="0" cellspacing="0" cellpadding="0">
<tbody>
<tr>
<td valign="top" style="padding:0cm 0cm 0cm 0cm">
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:
auto">
Using<br>
drools 5.1<br>
mvel 2-2.0.14<br>
<br>
In consequence (then) block : (dialect strict or not does not make a difference)<br>
<br>
Trying to sum up some numbers after a multiplication operation. For example :<br>
<br>
t.out = t.in2*t.in3 + t.in3*t.in4 + t.in2*t.in4;<br>
<br>
(the object t has all its attributes of the type String), all the t.in parameters are actually numbers-as-strings.<br>
<br>
So the multiplication is going on fine, as expected, but the addition (+) sign, is concatenating instead of adding.<br>
<br>
So the for inputs "1", "2" and "3", the result looks something like : 2.06.03.0 (i.e concetenated) instead of the expected 11.0.<br>
<br>
What is going worng How does the + operator decide to do concat instead of doing addition.<br>
<br>
Any documentation on this + operator logic ?<br>
<br>
Note : The above works fine when I use MVEL without Drools.<br>
<br>
Thanks <o:p></o:p></p>
</td>
</tr>
</tbody>
</table>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:10.0pt"> </span><o:p></o:p></p>
</div>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
<div class="MsoNormal" align="center" style="text-align:center">
<hr size="2" width="100%" align="center">
</div>
<p class="MsoNormal" style="margin-bottom:12.0pt"><span style="font-size:7.5pt;
font-family:"Arial","sans-serif";color:gray"><br>
**************************************************************************************<br>
This message is confidential and intended only for the addressee. If you have received this message in error, please immediately notify the postmaster@nds.com and delete it from your system as well as any copies. The content of e-mails as well as traffic data
may be monitored by NDS for employment and security purposes. To protect the environment please do not print this e-mail unless necessary.<br>
<br>
NDS Limited. Registered Office: One London Road, Staines, Middlesex, TW18 4EX, United Kingdom. A company registered in England and Wales. Registered no. 3080780. VAT no. GB 603 8808 40-00<br>
**************************************************************************************</span><o:p></o:p></p>
<div class="MsoNormal" align="center" style="text-align:center">
<hr size="2" width="100%" align="center">
</div>
<p class="MsoNormal"><span style="font-size:7.5pt;font-family:"Arial","sans-serif";
color:gray">This message is confidential and intended only for the addressee. If you have received this message in error, please immediately notify the postmaster@nds.com
and delete it from your system as well as any copies. The content of e-mails as well as traffic data may be monitored by NDS for employment and security purposes.<br>
To protect the environment please do not print this e-mail unless necessary.<br>
<br>
An NDS Group Limited company. www.nds.com</span><o:p></o:p></p>
</div>
<p class="MsoNormal" style="margin-bottom:12.0pt"><br>
-----Inline Attachment Follows-----<o:p></o:p></p>
<div>
<p class="MsoNormal">_______________________________________________<br>
rules-users mailing list<br>
<a href="/mc/compose?to=rules-users@lists.jboss.org"><u><span style="color:blue">rules-users@lists.jboss.org</span></u></a><br>
<a href="https://lists.jboss.org/mailman/listinfo/rules-users" target="_blank"><u><span style="color:blue">https://lists.jboss.org/mailman/listinfo/rules-users</span></u></a><o:p></o:p></p>
</div>
</td>
</tr>
</tbody>
</table>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Calibri","sans-serif""><o:p> </o:p></span></p>
</div>
</div>
<br>
<hr>
<font face="Arial" color="Gray" size="1"><br>
**************************************************************************************<br>
This message is confidential and intended only for the addressee. If you have received this message in error, please immediately notify the postmaster@nds.com and delete it from your system as well as any copies. The content of e-mails as well as traffic data
may be monitored by NDS for employment and security purposes. To protect the environment please do not print this e-mail unless necessary.<br>
<br>
NDS Limited. Registered Office: One London Road, Staines, Middlesex, TW18 4EX, United Kingdom. A company registered in England and Wales. Registered no. 3080780. VAT no. GB 603 8808 40-00<br>
**************************************************************************************<br>
</font><br>
<hr>
<font face="Arial" color="Gray" size="1">This message is confidential and intended only for the addressee. If you have received this message in error, please immediately notify the postmaster@nds.com and delete it from your system as well as any copies. The
content of e-mails as well as traffic data may be monitored by NDS for employment and security purposes.<br>
To protect the environment please do not print this e-mail unless necessary.<br>
<br>
An NDS Group Limited company. www.nds.com<br>
</font>
</body>
</html>