src/TSN/Xml.hs

   1 module TSN.Xml (
   2   parse_xmlfid,
   3   xml_prologue )
   4 where
   5
   6 import Data.Maybe (listToMaybe, mapMaybe)
   7 import Text.Read (readMaybe)
   8 import Text.XML.HXT.Core (
   9   (>>>),
  10   (/>),
  11   getChildren,
  12   getText,
  13   hasName,
  14   runLA,
  15   xreadDoc )
  16
  17 -- | A tiny parser written in HXT to extract the "XML_File_ID" element
  18 --   from a document.
  19 parse_xmlfid :: String -> Maybe Integer
  20 parse_xmlfid =
  21   listToMaybe . mapMaybe readMaybe . parse
  22   where
  23     parse :: String -> [String]
  24     parse =
  25       runLA (xreadDoc
  26                >>> hasName "message"
  27                />  hasName "XML_File_ID"
  28                >>> getChildren
  29                >>> getText)
  30
  31
  32 -- | The opening "tag" for the XML prologue.
  33 xml_prologue :: String
  34 xml_prologue = "<?xml "