HXQ-0.16.0: A Compiler from XQuery to Haskell Source code Contents Index

Text.XML.HXQ.XQuery

Contents The XML Data Representation The XQuery Compiler The XQuery Interpreter The XQuery Compiler with Database Connectivity The XQuery Interpreter with Database Connectivity Shredding and Publishing XML Documents Using a Relational Database Other Functions

Description

HXQ is a fast and space-efficient compiler from XQuery (the standard query language for XML) to embedded Haskell code. The translation is based on Haskell templates. It also provides an interpreter for evaluating ad-hoc XQueries read from input or from files and optional database connectivity using HDBC. For more information, look at http://lambda.uta.edu/HXQ/.

Synopsis

type Name = String type AttList = [(Name, String)] data XTree = XElem !Name !AttList !Int XTree [XTree] | XAttr !Name !String | XText !String | XInt !Int | XFloat !Double | XBool !Bool | XPI Name String | XGERef String | XComment String | XError String | XNull | XType Ast | XNoPad type XSeq = [XTree] putXSeq :: XSeq -> IO () xq :: String -> Q Exp xe :: String -> Q Exp qx xquery :: String -> IO XSeq eval :: XSeq -> IO XSeq xqdb :: String -> Q Exp xqueryDB :: String -> Connection -> IO XSeq genSchema :: Connection -> FilePath -> String -> IO Table shred :: Connection -> FilePath -> String -> IO () shredC :: String -> FilePath -> String -> Q Exp printSchema :: Connection -> String -> IO () createIndex :: Connection -> String -> String -> IO () connect :: String -> IO Connection disconnect :: Connection -> IO () commit :: Connection -> IO () rollback :: Connection -> IO ()

The XML Data Representation

type Name = String Source

Element tagname or attribute name

type AttList = [(Name, String)] Source

Attribute list

data XTree Source

A rose tree representation of XML data. An XML element is: XElem tagname atributes preorder parent children. The preorder numbering is the document order of elements. The parent is a cyclic reference to the parent element. Constructors XElem !Name !AttList !Int XTree [XTree] an XML tree node (element) XAttr !Name !String attribute construction XText !String an XML tree leaf (PCDATA) XInt !Int an XML tree leaf (int) XFloat !Double an XML tree leaf (double) XBool !Bool an XML tree leaf (boolean) XPI Name String processing instruction XGERef String general entity reference XComment String comment XError String error report XNull null value XType Ast type information XNoPad marker for no padding in XSeq Instances Eq XTree Show XTree

type XSeq = [XTree] Source

A sequence of XML fragments

putXSeq :: XSeq -> IO () Source

Print the XQuery result (which is a sequence of XML fragments) without buffering.

The XQuery Compiler

xq :: String -> Q Exp Source

Compile an XQuery that may perform IO (such as reading an XML document or calling a user function). When the compiled code is evaluated, it returns a value of type IO XSeq.

xe :: String -> Q Exp Source

Compile an XQuery expression that does not perform IO. When the compiled code is evaluated, it returns a value of type XSeq.

qx

The XQuery Interpreter

xquery :: String -> IO XSeq Source

Evaluate the XQuery using the interpreter.

eval :: XSeq -> IO XSeq Source

The XQuery interpreter as an XQuery function.

The XQuery Compiler with Database Connectivity

xqdb :: String -> Q Exp Source

Compile an XQuery that may perform IO and/or queries a database. When the compiled code is evaluated, it returns Connection -> IO XSeq.

The XQuery Interpreter with Database Connectivity

xqueryDB :: String -> Connection -> IO XSeq Source

Evaluate the XQuery with database connectivity using the interpreter.

Shredding and Publishing XML Documents Using a Relational Database

genSchema Source

:: Connection database connection -> FilePath XML document pathname -> String schema name -> IO Table Create a schema for an XML document into the database under the given name.

shred Source

:: Connection database connection -> FilePath XML document pathname -> String schema name -> IO () Store an XML document into the database under the given name.

shredC Source

:: String database name -> FilePath XML document pathname -> String schema name -> Q Exp Store an XML document into the database under the given name. Generates Haskell code.

printSchema Source

:: Connection database connection -> String schema name -> IO () Print the relational schema of the XML document stored in the database under the given name

createIndex Source

:: Connection database connection -> String schema name -> String the tag name of the elements to be indexed -> IO () Create a secondary index on tagname for the shredded document under the given name..

Other Functions

connect Source

:: String database name -> IO Connection Connect to a relational database

disconnect Source

:: Connection database connection -> IO () Disconnect from the relational database

commit Source

:: Connection database connection -> IO () commit the updates to the database

rollback Source

:: Connection database connection -> IO () rollback the updates from the database

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