Text.Interpolation.Nyan

Flexible interpolation quoter.

>>> import Text.Interpolation.Nyan
>>> let what = "nyan" in [int||Let's #{what}!|]
"Let's nyan!"

This package comes as an attempt to satisfy numerious needs of a production-scale code.

For the full tutorial, see Text.Interpolation.Nyan.Tutorial. And further goes the basic introduction.

Use of Buildable. By default

Values are interpolated via Buildable typeclass as it is more efficient and dedicated to human-readable errors.

Using Show is still available as:

>>> [int||Shown value: #s{value}|]

The produced text is also polymorphic by default and can be Text, lazy Text, String, Builder or other type.

Multiline text

By default, the interpolator strips indentation, one leading newline, and spaces before |]:

>>> :{
  [int||
    List:
      - a
      - b
   |]
:}
"List:\n  - a\n  - b\n"

When necessary, this behaviour can be fine-tuned with switches.

Switches

The section after int stands for the switches set.

For instance, to enable spaces trimming:

>>> [int|s| No extra spaces here |]
"No extra spaces here"

To fix the return type to be Text:

>>> [int|t|My text|]

To preview the resulting text at compilation stage, pass ! switch:

>>> [int|s!| My text: #{value}   |]
Reports "My text: ..."

This is reported as a build error, and substitutions are not performed. Put ! twice to also see all the invisible characters.

There are much more switches supported. To quicky ask for a help on switches on the go, put ? switch into the interpolator:

>>> [int|?||]
Fails with the help on switches

Customization

This interpolator allows for a variety of tunning, therefore such a name for the library.

• Aside from Buildable and Show support, one can define their own so-called rendering modes.
• The existing rendering modes can be hidden or grouped into modesets. For instance, there is a modeset Text.Interpolation.Nyan.RModes.Show with Show taken as the default rendering mode; it is used as the basic modeset in Text.Interpolation.Nyan.Show module.
• The set of switches enabled by default is also customizable.

Generally, once the user gets comfortable with the library, we encourage them to define their own variation of the interpolator that would serve their preferences, and include it in their custom preludes or util modules.

Documentation

int :: QuasiQuoter

The interpolator.

module Text.Interpolation.Nyan.RModes.CommonExtra

module Text.Interpolation.Nyan.RModes.Buildable