From e243cd696f97410ba7d25ffd2800936c16d160bf Mon Sep 17 00:00:00 2001
From: Albert Krewinkel <albert@zeitkraut.de>
Date: Fri, 21 Oct 2022 19:11:45 +0200
Subject: Lua: add pandoc.scaffolding.Writer (#8377)

This can be used to reduce boilerplate in custom writers.
---
 .../src/Text/Pandoc/Lua/Module/Scaffolding.hs      | 52 ++++++++++++++++++++++
 1 file changed, 52 insertions(+)
 create mode 100644 pandoc-lua-engine/src/Text/Pandoc/Lua/Module/Scaffolding.hs

(limited to 'pandoc-lua-engine/src/Text/Pandoc/Lua/Module')

diff --git a/pandoc-lua-engine/src/Text/Pandoc/Lua/Module/Scaffolding.hs b/pandoc-lua-engine/src/Text/Pandoc/Lua/Module/Scaffolding.hs
new file mode 100644
index 000000000..8bafe47cb
--- /dev/null
+++ b/pandoc-lua-engine/src/Text/Pandoc/Lua/Module/Scaffolding.hs
@@ -0,0 +1,52 @@
+{-# LANGUAGE OverloadedStrings #-}
+{- |
+   Module      : Text.Pandoc.Lua.Module.Scaffolding
+   Copyright   : Copyright © 2022 Albert Krewinkel, John MacFarlane
+   License     : GNU GPL, version 2 or above
+   Maintainer  : Albert Krewinkel <tarleb+pandoc@moltkeplatz.de>
+
+Scaffolding for custom Writers.
+-}
+module Text.Pandoc.Lua.Module.Scaffolding
+  ( documentedModule
+  ) where
+
+import HsLua
+import Text.Pandoc.Error (PandocError)
+import Text.Pandoc.Lua.Writer.Scaffolding (pushWriterScaffolding)
+import qualified Data.Text as T
+
+-- | The "pandoc.template" module.
+documentedModule :: Module PandocError
+documentedModule = Module
+  { moduleName = "pandoc.scaffolding"
+  , moduleDescription = T.unlines
+    [ "Scaffolding for custom writers."
+    ]
+  , moduleFields = [writerScaffolding]
+  , moduleOperations = []
+  , moduleFunctions = []
+  }
+
+-- | Template module functions.
+writerScaffolding :: Field PandocError
+writerScaffolding = Field
+  { fieldName = "Writer"
+  , fieldDescription = T.unlines
+    [ "An object to be used as a `Writer` function; the construct handles"
+    , "most of the boilerplate, expecting only render functions for all"
+    , "AST elements"
+    ]
+  , fieldPushValue = do
+      pushWriterScaffolding
+      -- pretend that it's a submodule so we get better error messages
+      getfield registryindex loaded
+      pushvalue (nth 2)
+      setfield (nth 2) (submod "Writer")
+      -- same for fields "Block" and "Inline"
+      getfield (nth 2) "Inline" *> setfield (nth 2) (submod "Writer.Inline")
+      getfield (nth 2) "Block" *> setfield (nth 2) (submod "Writer.Block")
+
+      pop 1 -- remove "LOADED_TABLE"
+  }
+ where submod x = moduleName documentedModule <> "." <> x
-- 
cgit v1.2.3