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GHC 9.10.3 · lts/ghc-9.10.x · 248f8f0 · 2026-10-05

Modulehxt-9.3.1.22Haskell2010

Text.XML.HXT.Arrow.XmlState.TypeDefs

the basic state arrows for XML processing

A state is needed for global processing options, like encoding options, document base URI, trace levels and error message handling

The state is separated into a user defined state and a system state. The system state contains variables for error message handling, for tracing, for the document base for accessing XML documents with relative references, e.g. DTDs, and a global key value store. This assoc list has strings as keys and lists of XmlTrees as values. It is used to store arbitrary XML and text values, e.g. user defined global options.

The user defined part of the store is in the default case empty, defined as (). It can be extended with an arbitray data type

  • 19 types
  • 104 values
  • Packagehxt-9.3.1.22
  • Exports123
  • LanguageHaskell2010
  • LicenceMIT
  • SourceTypeDefs.hs
typetype IOSArrow b c = IOStateArrow () b c
#

The arrow for stateful arrows with no user defined state

valuewithExtendedUserState
  1. :: s1
  2. -> IOStateArrow (s1, s0) b c
  3. -> IOStateArrow s0 b c
#

extend user state

Run an arrow with an extended user state component, The old component is stored together with a new one in a pair, the arrow is executed with this extended state, and the augmented state component is removed form the state when the arrow has finished its execution

valuewithOtherUserState :: s1 -> IOStateArrow s1 b c -> IOStateArrow s0 b c
#

change the type of user state

This conversion is useful, when running a state arrow with another structure of the user state, e.g. with () when executing some IO arrows

datadata XIOParseConfig
#

Constructors

datadata Selector s a
#

A Selector is a pair of an access function and a modifying function for reading and updating parts of a composite type

Constructors

Instances1Category