A description can be placed anywhere within a block to describe that block's purpose. In the case of declarations of variables-like objects, a description must be placed on the line directly beneath the declaration line. A variable-like object refers to variables, arguments and components. A description made up of two parts, a basic and a detail part.

### Basic Part

The basic part of a description being with !> and is used to give a brief outline of what the block is used for. This description is used as the subtitle on the block's documentation page, as well as the description displayed within lists. Note, a variable-like object can only contain a basic description part.

### Detail Part

Doctran will treat any line beginning with !>> as a detailed description component. The detailed part of a description is only seen within the blocks documentation page. Detailed descriptions can contain HTML or markdown. Note that section headings are given by <h2> tags in html or the ## in markdown as the level one heading is used for the object's name and type. Doctran will automatically make the content between each level two heading foldable.

If required, a description maybe split onto multiple lines by starting the next line with !> or !>> for basic and detailed components respectively.

### Example

An example of some valid descriptions are shown below.

type Vector_1d
!> A basic description.
!> Another line may be included and must be directly below the previous line.
!>> A detailed description.
!>> The same applies for a multi-line detailed descriptions.

real x_1
!> A basic description of a variable. This must be directly below the declaration.
end type


## Named Descriptions

Named descriptions allow the description of variable-like objects, where several of them are declared on a single line. Any line with the form !> NAME - DESCRIPTION, where NAME is a string of alpha numeric characters, will be interpreted by Doctran as a named description. As with all Fortran names the NAME specified is not case sensitive.

### Example

An example of some valid named descriptions are shown below.

type Vector_2d
real x_1, x_2
!> x_1 - A real variable holding the value of the vector in the x direction.
!> x_2 - A real variable holding the value of the vector in the y direction.
end type


## Alternative Commenting

Named descriptions allow for more flexibility when specifying your descriptions. Doctran will search within a block and also its parent block for names matching the description's name. This allows for a different style of commenting to be used as shown in the example below.

!> Vector_2d - A type containing two real components, representing the two degrees of freedom.
!>> Mathematically this type represents the following:
!>> $\vec{x} = \left(\begin{array}{c} x_1 \\ x_2 \end{array} \right)$
type Vector_2d
!> x_1 - A real variable holding the value of the vector in the x direction.
!> x_2 - A real variable holding the value of the vector in the y direction.
real x_1, x_2
end type