$xq=new XqueryLite();

$xq->init();

$result=$xq->evaluate_xqueryl($query);

Documentation

Classes

• XqueryLite

XqueryLite

Method Detail

XqueryLite

void XqueryLite()

This is the constructor receives nothing, does nothing, return nothing.

 

Parameters:

Returns:

Nothing

Throws:

None

init

void init()

This is an important method since it must be called before a query is evaluated (before each query) to initialize the interpreter internal state

 

Parameters:

Returns:

Nothing

Throws:

None

evaluate_xqueryl

string evaluate_xqueryl(string $query)

This method is used to evaluate an Xquery Lite 1.0 query, just pass the query as an argument and receive the result.

 

Parameters:

$query - The Xquery Lite 1.0 query

Returns:

The result of the query whatever it is

Throws:

Several exceptions can be reaised as warnings if an error occurs when parsing the query, tipically the query has a syntax error or the XML source can't be located.

_tokenize

array _tokenize(string $exp)

This private method receives a Xquery Lite expression (whatever is found between curly brackets) and returns an array of statements, for example v[0]=a for statament, v[1]=a let statement, v[2]=a where statement, v[3]=return statement.

 

Parameters:

$exp - An Xquery expression (without starting and ending curly brackets). Sentences must be sepperated by whitespace (blank, newline or tabs)

Returns:

An array where each array position contains an statement

Throws:

None

_get_root_name

string _get_root_name(object $node)

This method returns the name of the root element from an XML fragment passed as a node.

 

Parameters:

$node - A dom node

Returns:

The name of the root element

Throws:

None

_parse_for

string _parse_for(string $expr)

This method parses a for statement and puts the nodeset resulting from the for statement in the object result_sets member.

 

Parameters:

$expr - The for statement it must be in extended notation (can't admit several fors sepparated by commas)

Returns:

The name of the Xquery variable corresponding to the for statement.

Throws:

It can raise an error if the XML source is not found, if it is not well formed or if the Xpath expression in the for statement is wrong

_distinct

array _distinct(array $nodeset)

Filters a nodeset returning a nodeset without duplicate nodes, the normalize_elements function is used in order to compare nodes and find duplicate nodes in the nodeset.

 

Parameters:

$nodeset - Array of dom nodes

Returns:

An array of nodes (another nodeset) without duplicate nodes

Throws:

None

_normalize_elements

string _normalize_elements(object $node)

This function normalizes a dom subtree removing all whitespace elements thus producing a normalized representation of the subtree that can be used in comparisons.

 

Parameters:

$node - A dom node that is the root of the subtree to be normalized

Returns:

An string containing a normalized dump of the subtree

Throws:

None

_parse_var

string _parse_var(string $expr, boolean $norm)

This method parses an Xquery expression in the form $a/xpath_expr where $a is an Xquery Lite variable previously assigned by a for or let statement

 

Parameters:

$expr - The expression to be parsed
$norm - If this parameter is true the method returns a normalized representation of the result.

Returns:

A string representing the result, if the result is a nodeset then all nodes are concatenated one after the other.

Throws:

It can raise an exception if the xpath expression has an error or if the variable is not well formed XML

_count_var

int _count_var(string $expr)

This method parses a $a/xpath_expr expression and returns the number of elements in the nodeset, it is used to process count(expr) constructions in the query.

 

Parameters:

$expr - The expression

Returns:

The number of elements in the nodeset if no xpath expression is passed returns 1 if the variable exists if the nodeset is empty returns 0

Throws:

It can raise an error if the variable is not XML if it doesn't exist or it the Xpath expression is wrong.

_parse_where

boolean _parse_where(string $expr)

This method parses a where statement returning true/false after parsing the expresion

 

Parameters:

$expr - The where statement

Returns:

The result of the where expression

Throws:

If there's an error in the expression it raises an error

_parse_return

string _parse_return(string $expr)

This method parses a return statement returning the result of the return statement as a string if the return statement contains sub-queries then this method calls the evaluate_xqueryl recursively to process them

 

Parameters:

$expr - The return statement, everything found from the return word to the end of the query, including the return word.

Returns:

The result of the return statement

Throws:

Several errors can be raised since this can potentially call evaluate_xqueryl

_parse_let

void _parse_let(string $expr)

This parses a let statement updating the "bindings" object variable with the value of the expression for the designated variable.

 

Parameters:

$expr - The let statement

Returns:

nothing

Throws:

None

_split_fors

array _split_fors(string $exprs)

A for statement may include several for statements sepparated with commas (compact notation) this method splits the compact for notation in an array of extended for statements

 

Parameters:

$exprs - A for statement in compact or extended notation

Returns:

An array where each element is a for statement

Throws:

None

_parse_query

string _parse_query(string $query)

This method parses an Xquery Lite expression and returns the result, the expresion is a FLWR lite expression defined in the Xquery Lite 1.0 language this method identifies FOR, LET, WHERE and RETURN statements, and process them accordingly.

 

Parameters:

$query - The Xquery Lite expression to be parsed

Returns:

The result of the query

Throws:

If there's an error when parsing the query