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Module Xml

module Xml: sig .. end
Xml Light

Xml Light is a minimal Xml parser & printer for OCaml. It provide few functions to parse a basic Xml document into an OCaml data structure and to print back the data structures to an Xml document.

Xml Light has also support for DTD (Document Type Definition).

(c)Copyright 2002-2003 Nicolas Cannasse


Xml Data Structure

type xml = Xml_light_types.xml =
| Element of (string * (string * string) list * xml list)
| PCData of string (*
Xml Parsing

*)
An Xml node is either Element (tag-name, attributes, children) or PCData text

For easily parsing an Xml data source into an xml data structure, you can use theses functions. But if you want advanced parsing usage, please look at the XmlParser module. All the parsing functions can raise some exceptions, see the Exceptions section for more informations.
val parse_file : string -> xml
Parse the named file into an Xml data structure.
val parse_in : Pervasives.in_channel -> xml
Read the content of the in_channel and parse it into an Xml data structure.
val parse_string : string -> xml
Parse the string containing an Xml document into an Xml data structure.

Xml Exceptions


Several exceptions can be raised when parsing an Xml document : If the Xml document is containing a DTD, then some other exceptions can be raised, see the module Dtd for more informations.
type error_pos = Xml_light_errors.error_pos 
type error_msg = Xml_light_errors.xml_error_msg =
| UnterminatedComment
| UnterminatedString
| UnterminatedEntity
| IdentExpected
| CloseExpected
| NodeExpected
| AttributeNameExpected
| AttributeValueExpected
| EndOfTagExpected of string
| EOFExpected 
type error = error_msg * error_pos 
exception Error of error
exception File_not_found of string
val error : error -> string
Get a full error message from an Xml error.
val error_msg : error_msg -> string
Get the Xml error message as a string.
val line : error_pos -> int
Get the line the error occured at.
val range : error_pos -> int * int
Get the relative character range (in current line) the error occured at.
val abs_range : error_pos -> int * int
Get the absolute character range the error occured at.

Xml Functions

exception Not_element of xml
exception Not_pcdata of xml
exception No_attribute of string
val tag : xml -> string
tag xdata returns the tag value of the xml node. Raise Xml.Not_element if the xml is not an element
val pcdata : xml -> string
pcdata xdata returns the PCData value of the xml node. Raise Xml.Not_pcdata if the xml is not a PCData
val attribs : xml -> (string * string) list
attribs xdata returns the attribute list of the xml node. First string if the attribute name, second string is attribute value. Raise Xml.Not_element if the xml is not an element
val attrib : xml -> string -> string
attrib xdata "href" returns the value of the "href" attribute of the xml node (attribute matching is case-insensitive). Raise Xml.No_attribute if the attribute does not exists in the node's attribute list Raise Xml.Not_element if the xml is not an element
val children : xml -> xml list
children xdata returns the children list of the xml node Raise Xml.Not_element if the xml is not an element
val iter : (xml -> unit) -> xml -> unit
iter f xdata calls f on all children of the xml node. Raise Xml.Not_element if the xml is not an element
val map : (xml -> 'a) -> xml -> 'a list
map f xdata is equivalent to List.map f (Xml.children xdata) Raise Xml.Not_element if the xml is not an element
val fold : ('a -> xml -> 'a) -> 'a -> xml -> 'a
fold f init xdata is equivalent to List.fold_left f init (Xml.children xdata) Raise Xml.Not_element if the xml is not an element

Xml Printing

val to_string : xml -> string
Print the xml data structure into a compact xml string (without any user-readable formating ).
val to_string_fmt : xml -> string
Print the xml data structure into an user-readable string with tabs and lines break between different nodes.