====Substitutable Strings====

Many parts of the [[capture:welcome|Capture]] system allow you to replace text with the value of an //attribute// within your capture.

These will take any text in curly braces (between the '{' and '}' symbols), search for an attribute that matches that name, and replace the whole thing with the value of that attribute.

For instance, the following expression...

<code>
{Machine.Speed} > {Machine.Max Speed}
</code>

will become...

<code>
20 > 45
</code>

...when the value of 'Machine.Speed' is 20 and 'Max Speed' is 45.

Expressions generally follow PHP syntax.

===Concatenating Strings===

If you want to combine multiple strings together, use the //period// (.) symbol instead of the more traditional //plus// (+) symbol. Plus is only used for **numeric** addition.

For example, if we wanted to create a single attribute combining the //style//, //flavour// and //size// of the cupcake we are baking, the expression would be...

<code php>
{Product.Style}.'/'.{Product.Size}.'/'.{Product.Flavour}
</code>

...which would result in values such as 'Plain Large Banana' and 'Gluten-Free Mini Chocolate'.

===Equality===

Use double-equals ( == ) to check for values being equal.

===Functions===

You can call PHP functions in calculations.

These include...

**abs**(//amount//) - Returns the absolute value of the number \\
**round**(//amount//,//places//) - Rounds the value to the given number of decimal places \\
**sqrt**(//amount//) - Returns the square root of the result \\

A number of functions are prohibited for security reasons. These include...

**eval**, **system**, **passthru**, **exec**, **file_get_contents**, **open**, **readfile** etc.