The inner workings of DCL is very simple. The most fundamental terms are function, argument and value. All functions returns a string and takes named arguments in the form of a string. Here is a small example to show how it works. The code in this example will print the firstname from the contact card.
<% contact field="firstname" %>
| <% | – Tell the page we are about to run a DCL function |
| Contact | – What is the name of the function |
| Field | – The argument name |
| “firstname” | – The argument value |
| %> | – End DCL function |
Whitespace
Whitespace are non visible characters and may be used at will to make your DCL code cleaner and more readable. If you like you may code DCL like this.
| <% |
| contact |
| field=”firstname” |
| %> |
It is however used more if your DCL code lines becomes excessively long.
Functions
Function starts with “<%” and end with “%>”, a function returns a string which will be printed out in the page or used as an argument to another function. Here we make a link to our website using the user field “website” as an argument to the link function.
<% link url=<% user field="website" %> caption="Link to Website" %>
Strings
A string is a sequence of zero or more characters, in DCL a literal string is written with doublequotes.
"This is a string"
There is exactly one character thats needs to be escaped in a literal string, the doublequote. If you put 2 doublequotes in a row there will be 1 in the resulting string.
"There is only 1 "" in this string"
To concatenate strings we use the “+” character.
"This is a string" + "We add this string"
As functions returns a string you may use a function as an argument to another function (See 3.2), you may even concatenate functions and literal strings. The code below takes firstname and lastname from the contact card, put a space in between them and uppercase it all. Notice how we use whitespace to clean up this code.
<% upper string= <% contact field="firstname" %> + " " + <% contact field="lastname" %> %>