From d7cab5198269fbbdbc40f54a2ad7aeb83fee619f Mon Sep 17 00:00:00 2001
From: Albert Krewinkel <albert@zeitkraut.de>
Date: Tue, 21 Dec 2021 09:40:23 +0100
Subject: Lua: add new library function `pandoc.utils.type`.
The function behaves like the default `type` function from Lua's
standard library, but is aware of pandoc userdata types. A typical
use-case would be to determine the type of a metadata value.
---
src/Text/Pandoc/Lua/Module/Utils.hs | 12 ++++++++++++
1 file changed, 12 insertions(+)
(limited to 'src/Text/Pandoc/Lua/Module')
diff --git a/src/Text/Pandoc/Lua/Module/Utils.hs b/src/Text/Pandoc/Lua/Module/Utils.hs
index 439a9a50b..c1bb42410 100644
--- a/src/Text/Pandoc/Lua/Module/Utils.hs
+++ b/src/Text/Pandoc/Lua/Module/Utils.hs
@@ -21,6 +21,7 @@ import Control.Applicative ((<|>))
import Control.Monad ((<$!>))
import Data.Data (showConstr, toConstr)
import Data.Default (def)
+import Data.Maybe (fromMaybe)
import Data.Version (Version)
import HsLua as Lua
import HsLua.Class.Peekable (PeekError)
@@ -145,6 +146,17 @@ documentedModule = Module
<#> parameter peekTable "Block" "tbl" "a table"
=#> functionResult pushSimpleTable "SimpleTable" "SimpleTable object"
#? "Converts a table into an old/simple table."
+
+ , defun "type"
+ ### (\idx -> getmetafield idx "__name" >>= \case
+ TypeString -> fromMaybe mempty <$> tostring top
+ _ -> ltype idx >>= typename)
+ <#> parameter pure "any" "object" ""
+ =#> functionResult pushByteString "string" "type of the given value"
+ #? ("Pandoc-friendly version of Lua's default `type` function, " <>
+ "returning the type of a value. If the argument has a " <>
+ "string-valued metafield `__name`, then it gives that string. " <>
+ "Otherwise it behaves just like the normal `type` function.")
]
}
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