Skip to main content

Concatenating a string to a class constant in PHP

Today I wanted to concatenate a String value to a Class constant to get some task done. I wrote a line as follows.


class DeadlineNotifications extends AppraisalObject {

         const ROOT_PATH = '/var/www/dev/nus';
         const EMAIL_TEMPLATE_DIR = ROOT_PATH . '/lib/models/performance/emailTemplates/';


Expected value in second constant:
----------------
/var/www/dev/nus/lib/models/performance/emailTemplates/

Actual result:
--------------
Parse error: syntax error, unexpected '.', expecting ',' or ';'


In a way, some one can consider this thing as a bug of PHP. But this is not a bug. You can only initialize class constants with constant values. Here I have passed a statement which has to be evaluated at runtime. But the class constants are defined at compile time which comes earlier.
Labels:

Comments

Post a Comment

Popular posts from this blog

How to create a new module for vtiger...

Recently, I had to create a new module for vtigerCRM for my client in current working place. I did search in many places including the official vtiger sites, but couldn’t find a better documentation for my purpose. The latest vtiger version at that time was 5.0.3. Because I had some experience doing lots of core modifications for this system, I did decide to read the source code and find how to add a new module. Finally, I could create a new module and started the project. So, I thought it will be a good thing to write some thing on my blog about this topic, so that others who want to do this thing can read. Given below is a brief description about how to create a new module for vtiger CRM 5.0.3. Source code of this example module is also available to Download.
Step 01: Creating the module directory and minimum required files.
Create a directory called “newModule” inside your vtiger modules directory, or any other name that you prefer. Now, module index file should be created. Create a…
48 comments
Read more

Common Characteristics of Enterprise Applications

Last week, I was conducting a tech talk about “Architectural Patterns of Enterprise Applications” with our team. The discussion was mainly based on Marin Fowler's famous book “Patterns of Enterprise Application Architecture”. So, I thought, it's good to write something about that in my Blog. Given below are few common characteristics of Enterprise Applications. If any software product has the following characteristics, we can identify it as an Enterprise Application. These ware originally documented by “Martin Fowler”, in his book “Patterns of Enterprise Application Architecture”.

Persistent Data - Enterprise applications usually involve persistent data. The data is persistent because it needs to be around between multiple runs of the program—indeed, it usually needs to persist for several years. Also during this time there will be many changes in the programs that use it.
Lot of Data - There's usually a lot of data, a moderate system will have over 1 GB of data organized in…
Post a Comment
Read more

De Morgan's Laws in Programming

Recently, while I was reviewing some codes, I saw there were some conditional statements that check for the same condition but written in different ways. Most of these statements were written with common sense without using any mathematical analysis, since those are too simple to go for a more formal approach. The two identical conditional statements that has been written in different ways are given below.

01)

if ($comment['deleted'] == '1' || $comment['approved'] == '0') {
                unset($conversationsArray[$key]);
} else {
               ++$count;
}

02)

if ($comment['deleted'] == '0' && $comment['approved'] == '1') {
               ++$count;             
} else {
             unset($conversationsArray[$key]);
}

Obviously, the above lines say that the inverse of the first condition is equals to the second condition and vice versa. That is...

 ($comment['deleted'] == '1' || $comment['ap…
9 comments
Read more