This morning I was working on a small project to modify the layout of the attributes on a product page template, and it occurred to me that others might find this little trick about writing conditionals where you need to match a multitude of variables useful.

In this particular project, I needed conditionals for two purposes: one in one location of the template to check to see if the attribute template code was either the word “Length” or the word “Width” and the second in a separate location to check to see if the template code was either “LengthFraction” or “WidthFraction.”

Since I was trying to match the code against a list of variables, I could have written my conditional like so:

<mvt:if expr="l.settings:attribute:template_code IN 'LengthFraction, WidthFraction'">

Anyone else see a problem with this though? The above conditional, which checks to see if the content of the template code variable exists in either the words LengthFraction or WidthFraction will return true not only if the template code is actually LengthFraction or WidthFraction, but also if the template code is merely Length or Width.

So, we need to be a little more specific. Since I was only trying to match one of two different variables, I could have written my conditional like this instead:

<mvt:if expr="((l.settings:attribute:template_code EQ 'LengthFraction') OR (l.settings:attribute:template_code EQ 'WidthFraction'))">

That’s fine when you only have a couple of variables to test against, but if you have several codes you want to match up, there’s a much cleaner and easier way. By making use of Store Morph Technology’s (SMT) concatenating feature, you can use the IN expression to check against a list of several codes, without the risk of inexact matches.

Here’s the code:

<mvt:if expr="'|'$l.settings:attribute:template:code$'|' IN '|Length|Width|'">

And here’s how it works.

The very first element in the conditional is a string (enclosed by single quotes) consisting of a pipe character, aka | . Next to the string is a $ sign. In many scripting languages the $ sign is used to indicate a variable, but in SMT, the $ sign is a concatenator. That is, it takes whatever string or variable is in front of it, and joins it to whatever string or variable is after it.

The next element in our conditional is the SMT variable we are wanting to test, in this case, the attribute template code. It’s followed by another $ sign and another string consisting of a pipe character. The result is that the first part of our conditional expression consists of the template code surrounded by pipes: |Length| |LengthFraction| |Width| |WidthFraction| etc.

The second element in the conditional is a string, consisting of a list of the codes we want to match. The list begins and ends with a pipe character, and the codes in the list are also separated with pipe characters.

What this means is that if the conditional tries to match |Length| to |LengthFraction| it will now return false, since there isn’t an exact character to character match — although the |Length part of the first element is found in |LengthFraction| the pipe at the end of |Length| does not appear in that same position in |LengthFraction| and so the conditional will return false.

So there you have it. A complex conditional made short and sweet.

When Miva Merchant released MM5, they revolutionized the way the software worked “out of the box” and opened a whole new world of customization to ecommerce store owners. Using Store Morph Technology (SMT), store owners could completely and…well, I was going to say easily customize their stores to suit their needs, but the truth is that at first glance, SMT isn’t in fact all that easy.

One of the common complaints from new developers of MM sites, is the lack of documentation about SMT and how it works. The new owners of Miva Merchant are working hard to remedy the documentation void, but in the meantime, here’s a mini primer on SMT and some examples of the things you can do with it.

You’ll see SMT in MM’s page templates in a variety of different forms.

Variables

There are two types of variables in SMT: local variables, specific to the page you’re on, and global variables, which are available sitewide. The best way to find out what variables are available on a given page is to download the free Store Helper Module from Latu.net.

Variables are displayed on MM pages in a variety of ways. Note that variables always begin with an ampersand (&) and end with a semicolon (;).

&mvt:product:code;
&mvte:product:code;
&mvta:product:code;

Variables that begin with &mvte are “entity encoded.” This means that any characters they contain will be displayed on the page in their exact form — they will not be interpreted by the browser.

Variables that begin with &mvta are “attribute encoded.” This means that any characters they contain will be converted to the correct format for use in a link.

Tags

SMT tags look similar to XHTML tags in that they are surrounded by < >, they include name / value pairs, with the values surrounded by double quotes, and all SMT tags must be closed, either by using a trailing slash, or with a separate closing tag.

Items

SMT tags may call in specific page items. These tags start with mvt:item, and use name=”xyz” to identify which page item is being called. They may also include parameters that more specifically identify the content to be called in. They are frequently self closing, but may have a separate closing tag depending on their form.

<mvt:item name="html_profile" />

<mvt:item name="fonts" param="body_font" />
Some content here
</mvt:item>

Loops and arrays

SMT tags may be used to loop through an array, and display specific data associated with that array. Common uses for these tags include such things as displaying the products in a category or search result, listing all of the products in the basket, or listing available shipping methods. All loops must be closed with a separate closing tag after you’ve worked with the content you’re pulling from the array.

<mvt:foreach iterator="product" array="products">
Some stuff about each of the items in this array
</mvt:foreach>

Conditionals

Finally, SMT tags may be used to create conditionals. This is far and away one of the most useful aspects of SMT, and is the building block of the store owner’s ability to customize his or her store (at least in my opinion!). Writing conditionals is probably worthy of a post all its own, but here are some basics.

All conditionals start with mvt:if and contain an expression to test for. A very basic conditional might look like this. This conditional checks to see if the product code is equal to the string 12345, and if it is, displays some text. Note that the string is enclosed in single quotes.

<mvt:if expr="l.settings:product:code EQ '12345'">
Display some text.
</mvt:if>

Conditionals can also be set up to do one thing if the condition is true, and another thing if it is false.

<mvt:if expr="l.settings:product:code EQ '12345'">
Display some text.
<mvt:else>
Display some other text.
</mvt:if>

Or even…

<mvt:if expr="l.settings:product:code EQ '12345'">
Display some text.
<mvt:elseif expr="l.settings:product:code EQ '45678'">
Display some other text.
<mvt:else>
Display yet some other text.
</mvt:if>

Expressions can be combined to create extremely specific situations to test against. For instance, if you want to display some text only if the product code is 12345 and the customer is logged in, you would write your conditional something like this:

<mvt:if expr="((l.settings:product:code EQ '12345') AND (g.Basket:Cust_id))">
Display some text
</mvt:if>

You can also easily test for a match in a single string or a series of strings, by using CIN or IN. CIN is case insensitive; IN is case sensitive. The strings to test against are enclosed in single quotes, and if there is more than one, they are separated by commas or some other delimiter such as a pipe. The conditional below will return true if the product code is 12345 or 45678 or 67890.

<mvt:if expr="l.settings:product:code IN '12345,45678,67890'">
Display some text.
</mvt:if>

Note that the conditional above will also return true if the product code is 1234567, 012345, or 98712356789. It checks merely to see if the content of the first variable is included in the second. If you need to look for an exact match, you would be better to use a conditional like the following.

<mvt:if expr="((l.settings:product:code EQ '12345') OR (l.settings:product:code EQ '45678') OR (l.settings:product:code EQ '67890'))">
Display some text.
</mvt:if>

Once you get the hang of them, you’ll wonder how you ever did without the power of conditionals to control your shopper’s experience on your site. Below are some of the most common conditional operators, along with what they do.

Comments

Finally, one of the most useful, and underused in my opinion, features of SMT is the comment feature. By carefully commenting your work, you make it so much easier on yourself or another developer when it comes time to try to make updates or changes to existing customizations. SMT comments take the following form. They are not parsed by the server, and won’t appear in your html source code.

<mvt:comment>
Here is an explanation of what this section of code is going to do.
</mvt:comment>