| Copyright | Copyright (C) 2009-2016 John MacFarlane |
|---|---|
| License | GNU GPL, version 2 or above |
| Maintainer | John MacFarlane <jgm@berkeley.edu> |
| Stability | alpha |
| Portability | portable |
| Safe Haskell | None |
| Language | Haskell98 |
Text.Pandoc.Templates
Description
A simple templating system with variable substitution and conditionals. The following program illustrates its use:
import Data.Text
import Data.Aeson
import Text.Pandoc.Templates
data Employee = Employee { firstName :: String
, lastName :: String
, salary :: Maybe Int }
instance ToJSON Employee where
toJSON e = object [ "name" .= object [ "first" .= firstName e
, "last" .= lastName e ]
, "salary" .= salary e ]
employees :: [Employee]
employees = [ Employee "John" "Doe" Nothing
, Employee "Omar" "Smith" (Just 30000)
, Employee "Sara" "Chen" (Just 60000) ]
template :: Template
template = either error id $ compileTemplate
"$for(employee)$Hi, $employee.name.first$. $if(employee.salary)$You make $employee.salary$.$else$No salary data.$endif$$sep$\n$endfor$"
main = putStrLn $ renderTemplate template $ object ["employee" .= employees ]A slot for an interpolated variable is a variable name surrounded
by dollar signs. To include a literal $ in your template, use
$$. Variable names must begin with a letter and can contain letters,
numbers, _, -, and ..
The values of variables are determined by a JSON object that is
passed as a parameter to renderTemplate. So, for example,
title will return the value of the title field, and
employee.salary will return the value of the salary field
of the object that is the value of the employee field.
The value of a variable will be indented to the same level as the variable.
A conditional begins with $if(variable_name)$ and ends with $endif$.
It may optionally contain an $else$ section. The if section is
used if variable_name has a non-null value, otherwise the else section
is used.
Conditional keywords should not be indented, or unexpected spacing problems may occur.
The $for$ keyword can be used to iterate over an array. If
the value of the associated variable is not an array, a single
iteration will be performed on its value.
You may optionally specify separators using $sep$, as in the
example above.
- renderTemplate :: (ToJSON a, TemplateTarget b) => Template -> a -> b
- renderTemplate' :: (ToJSON a, TemplateTarget b) => String -> a -> b
- class TemplateTarget a where
- varListToJSON :: [(String, String)] -> Value
- compileTemplate :: Text -> Either String Template
- data Template
- getDefaultTemplate :: Maybe FilePath -> String -> IO (Either IOException String)
Documentation
renderTemplate :: (ToJSON a, TemplateTarget b) => Template -> a -> b Source #
renderTemplate' :: (ToJSON a, TemplateTarget b) => String -> a -> b Source #
Like renderTemplate, but compiles the template first,
raising an error if compilation fails.
class TemplateTarget a where Source #
Minimal complete definition