! Display element name and update indentation
public function start_elt(spce:text,name:text,nba:integer):integer
 writeln(spce,name)
 spce+="  "
end-function

! Update indentation when element closes
public function end_elt(spce:text):integer
 spce-="  "
end-function

declarations
 afct:array(range) of string
end-declarations

afct(XML_FCT_OPEN_ELT):="start_elt" ! define open element
afct(XML_FCT_CLOSE_ELT):="end_elt"  ! define close element
fopen("mydocument.xml",F_INPUT)
rts:=xmlparse(afct,1,text(""))
fclose(F_INPUT)

1. This function is an alternative approach to load for processing XML documents: instead of loading into memory the entire document this function calls a dedicated routine whenever it identifies an XML entity. For instance a specific function is called when an element is open and another one when it is closed. It is up to the Mosel program to decide how to handle the document via these event handling functions.

2. To each event type corresponds a specific function signature. These functions return an integer that decides whether parsing should continue: a non-zero value will cause the parsing to cancel (this value is used as the return value of xmlparse). The expected function signatures are:

XML_FCT_DECL

function xmldecl(ctx:ctxtype, vers:text, enc:text, std:integer):integer

XML_FCT_TXT

function text_node(ctx:ctxtype, type:integer, data:text):integer

XML_FCT_CDATA

function cdata_node(ctx:ctxtype, type:integer, data:text):integer

XML_FCT_COM

function comment_node(ctx:ctxtype, type:integer, data:text):integer

XML_FCT_DATA

function data_node(ctx:ctxtype, type:integer, data:text):integer

XML_FCT_PINST

function processing_instr(ctx:ctxtype, target:text, data:text):integer

XML_FCT_OPEN_ELT

function open_element(ctx:ctxtype, name:text, nba:integer):integer

XML_FCT_CLOSE_ELT

function close_element(ctx:ctxtype):integer

In addition to the pre-defined arguments these functions take a context as their first parameter. This variable (that can be of any type) is provided to the xmlparse routine and can be used by the event functions for storing progress information.
The type passed to the text node functions is the XML type corresponding to the function (namely XML_TXT, XML_CDATA, XML_COM, XML_DATA).
The open_element function receives the name of the element as well as the number of defined attributes. To retrieve these attributes xmlattr can be used.

3. An error message indicating the location of the error is displayed when the parsing fails or if an event function returns a negative value (a positive value also interrupts parsing but no message is displayed).