Lua: add new module `pandoc.format`.

The module provides functions to query the set of extensions supported
by formats, and the set of extension enabled per default.

1 files changed, 60 insertions, 0 deletions

diff --git a/pandoc-lua-engine/src/Text/Pandoc/Lua/Module/Format.hs b/pandoc-lua-engine/src/Text/Pandoc/Lua/Module/Format.hs
new file mode 100644
index 000000000..8fa0485fc
--- /dev/null
+++ b/pandoc-lua-engine/src/Text/Pandoc/Lua/Module/Format.hs
@@ -0,0 +1,60 @@
+{-# LANGUAGE OverloadedStrings #-}
+{- |
+   Module      : Text.Pandoc.Lua.Module.Format
+   Copyright   : © 2022 Albert Krewinkel
+   License     : GPL-2.0-or-later
+   Maintainer  : Albert Krewinkel <[email protected]>
+
+Lua module to handle pandoc templates.
+-}
+module Text.Pandoc.Lua.Module.Format
+  ( documentedModule
+  ) where
+
+import HsLua
+import Text.Pandoc.Error (PandocError)
+import Text.Pandoc.Extensions
+  ( getAllExtensions, getDefaultExtensions )
+import Text.Pandoc.Lua.ErrorConversion ()
+import Text.Pandoc.Lua.Marshal.Extensions (pushExtensions)
+
+import qualified Data.Text as T
+
+-- | The "pandoc.format" module.
+documentedModule :: Module PandocError
+documentedModule = Module
+  { moduleName = "pandoc.format"
+  , moduleDescription = T.unlines
+    [ "Pandoc formats and their extensions."
+    ]
+  , moduleFields = []
+  , moduleOperations = []
+  , moduleFunctions = functions
+  }
+
+-- | Extension module functions.
+functions :: [DocumentedFunction PandocError]
+functions =
+  [ defun "default_extensions"
+     ### liftPure getDefaultExtensions
+     <#> parameter peekText "string" "format" "format name"
+     =#> functionResult pushExtensions "FormatExtensions"
+           "default extensions enabled for `format`"
+     #? T.unlines
+        [ "Returns the list of default extensions of the given format; this"
+        , "function does not check if the format is supported, it will return"
+        , "a fallback list of extensions even for unknown formats."
+        ]
+
+  , defun "all_extensions"
+     ### liftPure getAllExtensions
+     <#> parameter peekText "string" "format" "format name"
+     =#> functionResult pushExtensions "FormatExtensions"
+           "all extensions supported for `format`"
+     #? T.unlines
+        [ "Returns the list of all valid extensions for a format."
+        , "No distinction is made between input and output, and an"
+        , "extension have an effect when reading a format but not when"
+        , "writing it, or *vice versa*."
+        ]
+  ]