DOM parsing (FDOM)¶
(Written by Jon Wakelin and Alberto García. Notes by Jon Wakelin)
The FDOM is a DOM level 1.0 implementation written in F95.
A list of the methods implemented follows in the next sections.
See also the examples in the doc/Examples/dom
subdirectory of the main
distribution.
Programming issues and warnings¶
There are two “gotchas” that the Fortran programmer should be aware of, and I can’t stress either strongly enough. Firstly the DOM, like many programming languages, starts counting from 0, and not 1, for this reason all do loops should run from 0 to length - 1. Secondly, we while we can not return an object in Fortran per se, we can return a pointer to an arbitrary structure containing mulitple members, including substructures (which is very much like returning an object). Therefore, you must use the pointer syntax:
program main
use xmlf90_dom
type(fnode), pointer :: object
type(fnode), pointer :: myNode
object => getParentNode(myNode)
and not
program main
use xmlf90_dom
type(fnode) :: object
type(fnode) :: myNode
object = getParentNode(myNode)
I can anticipate that these two issues (over running lists by counting beyond the last item and trying to assign a pointer with =) will be the cause of most programming errors using FDOM. But fairly soon you get used to it, if you already program in other languages, or already use pointers in Fortran there shouldn’t be any problem at all.
Possible memory leaks¶
Some of the routines, as written as Fortran functions, might cause memory leaks. To avoid this problem, The DFTB+ project (https://dftbplus.org) converted some of the routines to Fortran subroutines in a fork of the xmlf90 DOM code. We would be ideally interested in replacing the underlying string-variable implementations and keep the current interface, but we might end up merging the DFTB+ changes. Any help would be appreciated.
(Generic) Node Interface¶
getNodeName(node)
getNodevalue)
getNodeType(node)
hasChildNodes(node)
hasAttributes(node)
getParentNode(node)
getFirstChild(node)
getLastChild(node)
getNextSibling(node)
getPreviousSibling(node)
getOwnerDocument(node)
getAttributes(node)
getChildNodes(node)
setNodeValue(node, value)
appendChild(node, newChild)
removeChild(node, oldChild)
replaceChild(node, newChild, oldChild)
cloneNode(node, [deep])
isSameNode(node, node2)
insertBefore(node, newChild, refChild)
element Node Interface¶
getTagName(element)
getElementsByTagName(elment, tag)
getAttribute(element, name)
getAttributeNode(element, name)
setAttribute(element, name, value)
setAttributeNode(element, newAttribute)
removeAttribute(element, name)
document Node Interface¶
createTextNode(text)
createAttribute(name)
createElement(name)
createComment(data)
getElementsByTagName(document, tag)
attribute Node Interface¶
getName(attr)
getValue(attr)
setValue(attr, value)
nodeList Interface¶
item(nodeList, i)
getLength(nodeList)
namedNodeMap Interface¶
item(namedNodeMap, i)
getLength(namedNodeMap)
getNamedItem(namedNodeMap, name)
setNamedItem(namedNodeMap, name)
removeNamedItem(namedNodeMap, name)
A partial list of the interfaces of the methods implemented follows.
For a full listing, please see the code in subdirectory src/dom
of the
main distribution.
method arguments returns DOM Level
---------------------------------------- -------------------------- --------------------- -----------
getNodeName(node) type(fnode) :: node string 1.0
getNodeValue(node) type(fnode) :: node string 1.0
getNodeType(node) type(fnode) :: node (integer code) 1.0
getParentNode(node) type(fnode) :: node type(fnode) 1.0
getFirstChild(node) type(fnode) :: node type(fnode) 1.0
getLastChild(node) type(fnode) :: node type(fnode) 1.0
getPreviousSibling(node) type(fnode) :: node type(fnode) 1.0
getNextSibling(node) type(fnode) :: node type(fnode) 1.0
getOwnerDocument(node) type(fnode) :: node type(fnode) 1.0
getAttributes(node) type(fnode) :: node type(fnamedNodeMap) 1.0
getChildNodes(node) type(fnode) :: node type(fnodeList) 1.0
getOwnerDocument(node) type(fnode) :: node type(fnode) 1.0
appendChild(node, newChild) type(fnode) :: node\ type(fnode) 1.0
type(fnode) :: newChild
removeChild(node, oldChild) type(fnode) :: node\ type(fnode) 1.0
type(fnode) :: oldChild
replaceChild(node, newChild, oldChild) type(fnode) :: node\ type(fnode) 1.0
type(fnode) :: newChild\
type(fnode) :: oldChild
replaceChild(node, refChild, oldChild) type(fnode) :: node\ type(fnode) 1.0
type(fnode) :: refChild\
type(fnode) :: oldChild
hasChildren(node) type(fnode) :: node logical 1.0
hasAttributes type(fnode) :: node logical 2.0
isSameNode(node, node2) type(fnode) :: node\ logical 3.0
type(fnode) :: node2
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