if

Conditionals Flow Control

The if statement allows for conditional processing of code blocks. In case the given expression evaluates to false, an optional else block is processed instead.

<@ if @{ variable } > 5 @>
  ...
<@ else @>
  ...
<@ end @>

Expressions

Automad understands two types of expressions. You can either test whether a variable has a value, or compare two operands. Operands can be variables, strings or numbers.

<# Test if a variable has a value. #>
<@ if @{ variable } @>
  ...
<@ end @>

<# Compare a variable to the string 'Test'. #>
<@ if @{ variable } = 'Test' @>
  ...
<@ end @>

<# Test whether a variable is greater than 5. #>
<@ if @{ variable } > 5 @>
  ...
<@ end @>

A variable is considered empty in case it is not defined or its value is either 0, false or an empty string.

Comparison Operators

The following operators can be used to compare two operands:

=
Equality — true if both operands have the same value.
!=
Inequality — true if both operands are not equal.
>
Greater than — true if the left operand is greater than the right one.
>=
Greater or equal — true if the left operand is greater than or equal to the right one.
<
Smaller than — true if the left operand is smaller than the right one.
<=
Smaller or equal — true if the left operand is smaller than or equal to the right one.

Logical Operators

The following operators can be used to negate or combine expressions:

!
Negates a variable test — true if a variable is empty.
not
An alias for !.
and
Combines two expressions — true if both expressions evaluate to true.
or
Combines two expressions — true if at least one of them evaluates to true.

Multiple expressions can also be chained to one combined expression:

<@ if not @{ variable1 } and @{ variable2 } = 'Test' or @{ variable3 } > 5 @>
  ...
<@ end @>

Examples

Testing whether a variable is not empty:

<@ if @{ variable } @>
  ...
<@ end @>

To invert the test above, use the ! or not operators:

<# Using "not" #>
<@ if not @{ variable } @>
  ...
<@ end @>
<# Or alternatively "!" #>
<@ if !@{ variable } @>
  ...
<@ end @>

Testing values with a default:

<@ if @{ variable | def (1) } >= 5 @>
  ...
<@ end @>

Combining expressions in order to test a range:

<@ if @{ variable } >= 5 and @{ variable } < 10 @>
  ...
<@ end @>

Filters can also be used in expressions. The following example is taken from the Standard Lite theme and only includes a table of contents in case the template name contains _toc:

<@ if @{ template | match ('/_toc/') } @>
  <@ toc.php @>
<@ end @>
foreach with
Control Structures
As in other languages, control structures are statements that dynamically determine the flow of rendering based on the evaluation of content and variables. Automad knows four different control structures: for, foreach, if and with. In contrast to function calls, control structures always wrap a block of code and can therefore also be nested.
for
The for loop iterates a range of integer values. Within the code block of the loop, the current value is represented by the :i runtime variable.
foreach
The foreach loop iterates collections and lists of files. Depending on the type of list, Automad provides different runtime variables within the code block of the loop to refer to the current item. The :i variable always contains the index of the current iteration.
with
The with statement processes a block of code within the context of a given page or file. When using the URL of a page or one of the keywords prev and next as argument, the context changes to that page. When using a file path, the related runtime variables can be used and images can be resized or cropped directly. In case there is no matching page or file, an optional else block is processed instead.