Text.XML.Light.Cursor

xml-1.3.7: A simple XML library.

Copyright | (c) Galois, Inc. 2008
License | BSD3
Maintainer | Iavor S. Diatchki <diatchki@galois.com>
Stability | provisional
Portability | portable
Safe Haskell | Safe
Language | Haskell98

Text.XML.Light.Cursor

Contents

- Conversions
- Moving around
  - Searching
- Node classification
- Updates
  - Inserting content
  - Removing content

Description

XML cursors for working XML content withing the context of an XML document. This implementation is based on the general tree zipper written by Krasimir Angelov and Iavor S. Diatchki.

Synopsis

- data Tag = Tag {
  - tagName :: QName
  - tagAttribs :: [Attr]
  - tagLine :: Maybe Line
  }
- getTag :: Element -> Tag
- setTag :: Tag -> Element -> Element
- fromTag :: Tag -> [Content] -> Element
- data Cursor = Cur {
  - current :: Content
  - lefts :: [Content]
  - rights :: [Content]
  - parents :: Path
  }
- type Path = [([Content], Tag, [Content])]
- fromContent :: Content -> Cursor
- fromElement :: Element -> Cursor
- fromForest :: [Content] -> Maybe Cursor
- toForest :: Cursor -> [Content]
- toTree :: Cursor -> Content
- parent :: Cursor -> Maybe Cursor
- root :: Cursor -> Cursor
- getChild :: Int -> Cursor -> Maybe Cursor
- firstChild :: Cursor -> Maybe Cursor
- lastChild :: Cursor -> Maybe Cursor
- left :: Cursor -> Maybe Cursor
- right :: Cursor -> Maybe Cursor
- nextDF :: Cursor -> Maybe Cursor
- findChild :: (Cursor -> Bool) -> Cursor -> Maybe Cursor
- findLeft :: (Cursor -> Bool) -> Cursor -> Maybe Cursor
- findRight :: (Cursor -> Bool) -> Cursor -> Maybe Cursor
- findRec :: (Cursor -> Bool) -> Cursor -> Maybe Cursor
- isRoot :: Cursor -> Bool
- isFirst :: Cursor -> Bool
- isLast :: Cursor -> Bool
- isLeaf :: Cursor -> Bool
- isChild :: Cursor -> Bool
- hasChildren :: Cursor -> Bool
- getNodeIndex :: Cursor -> Int
- setContent :: Content -> Cursor -> Cursor
- modifyContent :: (Content -> Content) -> Cursor -> Cursor
- modifyContentM :: Monad m => (Content -> m Content) -> Cursor -> m Cursor
- insertLeft :: Content -> Cursor -> Cursor
- insertRight :: Content -> Cursor -> Cursor
- insertGoLeft :: Content -> Cursor -> Cursor
- insertGoRight :: Content -> Cursor -> Cursor
- removeLeft :: Cursor -> Maybe (Content, Cursor)
- removeRight :: Cursor -> Maybe (Content, Cursor)
- removeGoLeft :: Cursor -> Maybe Cursor
- removeGoRight :: Cursor -> Maybe Cursor
- removeGoUp :: Cursor -> Maybe Cursor

# Documentation

data Tag

Constructors

Tag |
Fields tagName :: QName tagAttribs :: [Attr] tagLine :: Maybe Line

Instances

Show Tag |

getTag :: Element -> Tag

setTag :: Tag -> Element -> Element

fromTag :: Tag -> [Content] -> Element

data Cursor

The position of a piece of content in an XML document.

Constructors

Cur |
Fields current :: Content The currently selected content. lefts :: [Content] Siblings on the left, closest first. rights :: [Content] Siblings on the right, closest first. parents :: Path The contexts of the parent elements of this location.

Instances

Show Cursor |

type Path = [([Content], Tag, [Content])]

# Conversions

fromContent :: Content -> Cursor

A cursor for the given content.

fromElement :: Element -> Cursor

A cursor for the given element.

fromForest :: [Content] -> Maybe Cursor

The location of the first tree in a forest.

toForest :: Cursor -> [Content]

Computes the forest containing this location.

toTree :: Cursor -> Content

Computes the tree containing this location.

# Moving around

parent :: Cursor -> Maybe Cursor

The parent of the given location.

root :: Cursor -> Cursor

The top-most parent of the given location.

getChild :: Int -> Cursor -> Maybe Cursor

The child with the given index (starting from 0).

firstChild :: Cursor -> Maybe Cursor

The first child of the given location.

lastChild :: Cursor -> Maybe Cursor

The last child of the given location.

left :: Cursor -> Maybe Cursor

The left sibling of the given location.

right :: Cursor -> Maybe Cursor

The right sibling of the given location.

nextDF :: Cursor -> Maybe Cursor

The next position in a left-to-right depth-first traversal of a document: either the first child, right sibling, or the right sibling of a parent that has one.

## Searching

findChild :: (Cursor -> Bool) -> Cursor -> Maybe Cursor

The first child that satisfies a predicate.

findLeft :: (Cursor -> Bool) -> Cursor -> Maybe Cursor

Find the next left sibling that satisfies a predicate.

findRight :: (Cursor -> Bool) -> Cursor -> Maybe Cursor

Find the next right sibling that satisfies a predicate.

findRec :: (Cursor -> Bool) -> Cursor -> Maybe Cursor

Perform a depth first search for a descendant that satisfies the given predicate.

# Node classification

isRoot :: Cursor -> Bool

Are we at the top of the document?

isFirst :: Cursor -> Bool

Are we at the left end of the the document?

isLast :: Cursor -> Bool

Are we at the right end of the document?

isLeaf :: Cursor -> Bool

Are we at the bottom of the document?

isChild :: Cursor -> Bool

Do we have a parent?

hasChildren :: Cursor -> Bool

Do we have children?

getNodeIndex :: Cursor -> Int

Get the node index inside the sequence of children

# Updates

setContent :: Content -> Cursor -> Cursor

Change the current content.

modifyContent :: (Content -> Content) -> Cursor -> Cursor

Modify the current content.

modifyContentM :: Monad m => (Content -> m Content) -> Cursor -> m Cursor

Modify the current content, allowing for an effect.

## Inserting content

insertLeft :: Content -> Cursor -> Cursor

Insert content to the left of the current position.

insertRight :: Content -> Cursor -> Cursor

Insert content to the right of the current position.

insertGoLeft :: Content -> Cursor -> Cursor

Insert content to the left of the current position. The new content becomes the current position.

insertGoRight :: Content -> Cursor -> Cursor

Insert content to the right of the current position. The new content becomes the current position.

## Removing content

removeLeft :: Cursor -> Maybe (Content, Cursor)

Remove the content on the left of the current position, if any.

removeRight :: Cursor -> Maybe (Content, Cursor)

Remove the content on the right of the current position, if any.

removeGoLeft :: Cursor -> Maybe Cursor

Remove the current element. The new position is the one on the left.

removeGoRight :: Cursor -> Maybe Cursor

Remove the current element. The new position is the one on the right.

removeGoUp :: Cursor -> Maybe Cursor

Remove the current element. The new position is the parent of the old position.