eol-style
svn: r7803
This commit is contained in:
Jay McCarthy
parent
a4023f2ebe
commit
2204f32678
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@ -1,114 +1,114 @@
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SSAX Package
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============
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A SSAX functional XML parsing framework consists of a DOM/SXML parser, a SAX
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parser, and a supporting library of lexing and parsing procedures. The
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procedures in the package can be used separately to tokenize or parse various
|
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pieces of XML documents. The framework supports XML Namespaces, character,
|
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internal and external parsed entities, attribute value normalization,
|
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processing instructions and CDATA sections. The package includes a
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semi-validating SXML parser: a DOM-mode parser that is an instantiation of
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a SAX parser (called SSAX).
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SSAX is a full-featured, algorithmically optimal, pure-functional parser,
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which can act as a stream processor. SSAX is an efficient SAX parser that is
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easy to use. SSAX minimizes the amount of application-specific state that has
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to be shared among user-supplied event handlers. SSAX makes the maintenance
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of an application-specific element stack unnecessary, which eliminates several
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classes of common bugs. SSAX is written in a pure-functional subset of Scheme.
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Therefore, the event handlers are referentially transparent, which makes them
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easier for a programmer to write and to reason about. The more expressive,
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reliable and easier to use application interface for the event-driven XML
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parsing is the outcome of implementing the parsing engine as an enhanced tree
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fold combinator, which fully captures the control pattern of the depth-first
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tree traversal.
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-------------------------------------------------
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Quick start
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; procedure: ssax:xml->sxml PORT NAMESPACE-PREFIX-ASSIG
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;
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; This is an instance of a SSAX parser that returns an SXML
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; representation of the XML document to be read from PORT.
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; NAMESPACE-PREFIX-ASSIG is a list of (USER-PREFIX . URI-STRING)
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; that assigns USER-PREFIXes to certain namespaces identified by
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; particular URI-STRINGs. It may be an empty list.
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; The procedure returns an SXML tree. The port points out to the
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; first character after the root element.
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(define (ssax:xml->sxml port namespace-prefix-assig) ...)
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; procedure: pre-post-order TREE BINDINGS
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;
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; Traversal of an SXML tree or a grove:
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; a <Node> or a <Nodelist>
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;
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; A <Node> and a <Nodelist> are mutually-recursive datatypes that
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; underlie the SXML tree:
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; <Node> ::= (name . <Nodelist>) | "text string"
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; An (ordered) set of nodes is just a list of the constituent nodes:
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; <Nodelist> ::= (<Node> ...)
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; Nodelists, and Nodes other than text strings are both lists. A
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; <Nodelist> however is either an empty list, or a list whose head is
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; not a symbol (an atom in general). A symbol at the head of a node is
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; either an XML name (in which case it's a tag of an XML element), or
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; an administrative name such as '@'.
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; See SXPath.scm and SSAX.scm for more information on SXML.
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;
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;
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; Pre-Post-order traversal of a tree and creation of a new tree:
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; pre-post-order:: <tree> x <bindings> -> <new-tree>
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; where
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; <bindings> ::= (<binding> ...)
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; <binding> ::= (<trigger-symbol> *preorder* . <handler>) |
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; (<trigger-symbol> *macro* . <handler>) |
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; (<trigger-symbol> <new-bindings> . <handler>) |
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; (<trigger-symbol> . <handler>)
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; <trigger-symbol> ::= XMLname | *text* | *default*
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; <handler> :: <trigger-symbol> x [<tree>] -> <new-tree>
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;
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; The pre-post-order function visits the nodes and nodelists
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; pre-post-order (depth-first). For each <Node> of the form (name
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; <Node> ...) it looks up an association with the given 'name' among
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; its <bindings>. If failed, pre-post-order tries to locate a
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; *default* binding. It's an error if the latter attempt fails as
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; well. Having found a binding, the pre-post-order function first
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; checks to see if the binding is of the form
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; (<trigger-symbol> *preorder* . <handler>)
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; If it is, the handler is 'applied' to the current node. Otherwise,
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; the pre-post-order function first calls itself recursively for each
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; child of the current node, with <new-bindings> prepended to the
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; <bindings> in effect. The result of these calls is passed to the
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; <handler> (along with the head of the current <Node>). To be more
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; precise, the handler is _applied_ to the head of the current node
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; and its processed children. The result of the handler, which should
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; also be a <tree>, replaces the current <Node>. If the current <Node>
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; is a text string or other atom, a special binding with a symbol
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; *text* is looked up.
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;
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; A binding can also be of a form
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; (<trigger-symbol> *macro* . <handler>)
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; This is equivalent to *preorder* described above. However, the result
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; is re-processed again, with the current stylesheet.
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;
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(define (pre-post-order tree bindings) ...)
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-------------------------------------------------
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Additional tools included into the package
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1. "access-remote.ss"
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Uniform access to local and remote resources
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Resolution for relative URIs in accordance with RFC 2396
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2. "id.ss"
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Creation and manipulation of the ID-index for a faster access to SXML elements
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by their unique ID
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Provides the DTD parser for extracting ID attribute declarations
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3. "xlink-parser.ss"
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Parser for XML documents that contain XLink elements
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4. "multi-parser.ss"
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SSAX multi parser: combines several specialized parsers into one
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Provides creation of parent pointers to SXML document constructed
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SSAX Package
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============
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A SSAX functional XML parsing framework consists of a DOM/SXML parser, a SAX
|
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parser, and a supporting library of lexing and parsing procedures. The
|
||||
procedures in the package can be used separately to tokenize or parse various
|
||||
pieces of XML documents. The framework supports XML Namespaces, character,
|
||||
internal and external parsed entities, attribute value normalization,
|
||||
processing instructions and CDATA sections. The package includes a
|
||||
semi-validating SXML parser: a DOM-mode parser that is an instantiation of
|
||||
a SAX parser (called SSAX).
|
||||
|
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SSAX is a full-featured, algorithmically optimal, pure-functional parser,
|
||||
which can act as a stream processor. SSAX is an efficient SAX parser that is
|
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easy to use. SSAX minimizes the amount of application-specific state that has
|
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to be shared among user-supplied event handlers. SSAX makes the maintenance
|
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of an application-specific element stack unnecessary, which eliminates several
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classes of common bugs. SSAX is written in a pure-functional subset of Scheme.
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Therefore, the event handlers are referentially transparent, which makes them
|
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easier for a programmer to write and to reason about. The more expressive,
|
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reliable and easier to use application interface for the event-driven XML
|
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parsing is the outcome of implementing the parsing engine as an enhanced tree
|
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fold combinator, which fully captures the control pattern of the depth-first
|
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tree traversal.
|
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-------------------------------------------------
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Quick start
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; procedure: ssax:xml->sxml PORT NAMESPACE-PREFIX-ASSIG
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;
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; This is an instance of a SSAX parser that returns an SXML
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; representation of the XML document to be read from PORT.
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; NAMESPACE-PREFIX-ASSIG is a list of (USER-PREFIX . URI-STRING)
|
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; that assigns USER-PREFIXes to certain namespaces identified by
|
||||
; particular URI-STRINGs. It may be an empty list.
|
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; The procedure returns an SXML tree. The port points out to the
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; first character after the root element.
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(define (ssax:xml->sxml port namespace-prefix-assig) ...)
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|
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; procedure: pre-post-order TREE BINDINGS
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;
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; Traversal of an SXML tree or a grove:
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; a <Node> or a <Nodelist>
|
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;
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; A <Node> and a <Nodelist> are mutually-recursive datatypes that
|
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; underlie the SXML tree:
|
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; <Node> ::= (name . <Nodelist>) | "text string"
|
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; An (ordered) set of nodes is just a list of the constituent nodes:
|
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; <Nodelist> ::= (<Node> ...)
|
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; Nodelists, and Nodes other than text strings are both lists. A
|
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; <Nodelist> however is either an empty list, or a list whose head is
|
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; not a symbol (an atom in general). A symbol at the head of a node is
|
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; either an XML name (in which case it's a tag of an XML element), or
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; an administrative name such as '@'.
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; See SXPath.scm and SSAX.scm for more information on SXML.
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;
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;
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; Pre-Post-order traversal of a tree and creation of a new tree:
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; pre-post-order:: <tree> x <bindings> -> <new-tree>
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; where
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; <bindings> ::= (<binding> ...)
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; <binding> ::= (<trigger-symbol> *preorder* . <handler>) |
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; (<trigger-symbol> *macro* . <handler>) |
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; (<trigger-symbol> <new-bindings> . <handler>) |
|
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; (<trigger-symbol> . <handler>)
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; <trigger-symbol> ::= XMLname | *text* | *default*
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; <handler> :: <trigger-symbol> x [<tree>] -> <new-tree>
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;
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; The pre-post-order function visits the nodes and nodelists
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; pre-post-order (depth-first). For each <Node> of the form (name
|
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; <Node> ...) it looks up an association with the given 'name' among
|
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; its <bindings>. If failed, pre-post-order tries to locate a
|
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; *default* binding. It's an error if the latter attempt fails as
|
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; well. Having found a binding, the pre-post-order function first
|
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; checks to see if the binding is of the form
|
||||
; (<trigger-symbol> *preorder* . <handler>)
|
||||
; If it is, the handler is 'applied' to the current node. Otherwise,
|
||||
; the pre-post-order function first calls itself recursively for each
|
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; child of the current node, with <new-bindings> prepended to the
|
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; <bindings> in effect. The result of these calls is passed to the
|
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; <handler> (along with the head of the current <Node>). To be more
|
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; precise, the handler is _applied_ to the head of the current node
|
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; and its processed children. The result of the handler, which should
|
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; also be a <tree>, replaces the current <Node>. If the current <Node>
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; is a text string or other atom, a special binding with a symbol
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; *text* is looked up.
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;
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; A binding can also be of a form
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; (<trigger-symbol> *macro* . <handler>)
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; This is equivalent to *preorder* described above. However, the result
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; is re-processed again, with the current stylesheet.
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;
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(define (pre-post-order tree bindings) ...)
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-------------------------------------------------
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Additional tools included into the package
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|
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1. "access-remote.ss"
|
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Uniform access to local and remote resources
|
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Resolution for relative URIs in accordance with RFC 2396
|
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|
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2. "id.ss"
|
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Creation and manipulation of the ID-index for a faster access to SXML elements
|
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by their unique ID
|
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Provides the DTD parser for extracting ID attribute declarations
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|
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3. "xlink-parser.ss"
|
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Parser for XML documents that contain XLink elements
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|
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4. "multi-parser.ss"
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SSAX multi parser: combines several specialized parsers into one
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Provides creation of parent pointers to SXML document constructed
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|
|
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@ -1,10 +1,10 @@
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(module info (lib "infotab.ss" "setup")
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(define name "ssax")
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(define blurb
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(list "SSAX functional XML parsing framework "
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"to inter-convert between an angular-bracket and "
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"an S-expression-based notations for markup documents"))
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(define primary-file "ssax.ss")
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(define doc.txt "doc.txt")
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(define categories '(xml))
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)
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(module info (lib "infotab.ss" "setup")
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(define name "ssax")
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(define blurb
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(list "SSAX functional XML parsing framework "
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"to inter-convert between an angular-bracket and "
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"an S-expression-based notations for markup documents"))
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(define primary-file "ssax.ss")
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(define doc.txt "doc.txt")
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(define categories '(xml))
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)
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|
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@ -1,376 +1,376 @@
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SXML Package
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============
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SXML package contains a collection of tools for processing markup documents
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(XML, XHTML, HTML) in the form of S-expressions (SXML, SHTML)
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You can find the API documentation in:
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http://modis.ispras.ru/Lizorkin/Apidoc/index.html
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SXML tools tutorial (under construction):
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http://modis.ispras.ru/Lizorkin/sxml-tutorial.html
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==========================================================================
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Description of the main high-level package components
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-----------------------------------------------------
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1. SXML-tools
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2. SXPath - SXML Query Language
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3. SXPath with context
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4. DDO SXPath
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5. Functional-style modification tool for SXML
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6. STX - Scheme-enabled XSLT processor
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7. XPathLink - query language for a set of linked documents
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-------------------------------------------------
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1. SXML-tools
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XML is XML Infoset represented as native Scheme data - S-expressions.
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Any Scheme programm can manipulate SXML data directly, and DOM-like API is not
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necessary for SXML/Scheme applications.
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SXML-tools (former DOMS) is just a set of handy functions which may be
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convenient for some popular operations on SXML data.
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library file: Bigloo, Chicken, Gambit: "sxml/sxml-tools.scm"
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PLT: "sxml-tools.ss"
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http://www.pair.com/lisovsky/xml/sxmltools/
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-------------------------------------------------
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2. SXPath - SXML Query Language
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SXPath is a query language for SXML. It treats a location path as a composite
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query over an XPath tree or its branch. A single step is a combination of a
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projection, selection or a transitive closure. Multiple steps are combined via
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join and union operations.
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Lower-level SXPath consists of a set of predicates, filters, selectors and
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combinators, and higher-level abbreviated SXPath functions which are
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implemented in terms of lower-level functions.
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Higher level SXPath functions are dealing with XPath expressions which may be
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represented as a list of steps in the location path ("native" SXPath):
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(sxpath '(table (tr 3) td @ align))
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or as a textual representation of XPath expressions which is compatible with
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W3C XPath recommendation ("textual" SXPath):
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(sxpath "table/tr[3]/td/@align")
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An arbitrary converter implemented as a Scheme function may be used as a step
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in location path of "native" SXPath, which makes it extremely powerful and
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flexible tool. On other hand, a lot of W3C Recommendations such as XSLT,
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XPointer, XLink depends on a textual XPath expressions.
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It is possible to combine "native" and "textual" location paths and location
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step functions in one query, constructing an arbitrary XML query far beyond
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capabilities of XPath. For example, the query
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(sxpath `("document/chapter[3]" ,relevant-links @ author)
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makes a use of location step function relevant-links which implements an
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arbitrary algorithm in Scheme.
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SXPath may be considered as a compiler from abbreviated XPath (extended with
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native SXPath and location step functions) to SXPath primitives.
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library file: Bigloo, Chicken, Gambit: "sxml/sxpath.scm"
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PLT: "sxpath.ss"
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http://www.pair.com/lisovsky/query/sxpath/
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-------------------------------------------------
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3. SXPath with context
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SXPath with context provides the effective implementation for XPath reverse
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axes ("parent::", "ancestor::" and such) on SXML documents.
|
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|
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The limitation of SXML is the absense of an upward link from a child to its
|
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parent, which makes the straightforward evaluation of XPath reverse axes
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ineffective. The previous approach for evaluating reverse axes in SXPath was
|
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searching for a parent from the root of the SXML tree.
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SXPath with context provides the fast reverse axes, which is achieved by
|
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storing previously visited ancestors of the context node in the context.
|
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With a special static analysis of an XPath expression, only the minimal
|
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required number of ancestors is stored in the context on each location step.
|
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library file: Bigloo, Chicken, Gambit: "sxml/xpath-context.scm"
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PLT: "xpath-context_xlink.ss"
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-------------------------------------------------
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4. DDO SXPath
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The optimized SXPath that implements distinct document order (DDO) of the
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nodeset produced.
|
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|
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Unlike conventional SXPath and SXPath with context, DDO SXPath guarantees that
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the execution time is at worst polynomial of the XPath expression size and of
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the SXML document size.
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|
||||
The API of DDO SXPath is compatible of that in conventional SXPath. The main
|
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following kinds of optimization methods are designed and implemented in DDO
|
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SXPath:
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- All XPath axes are implemented to keep a nodeset in distinct document
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||||
order (DDO). An axis can now be considered as a converter:
|
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nodeset_in_DDO --> nodeset_in_DDO
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|
||||
- Type inference for XPath expressions allows determining whether a
|
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predicate involves context-position implicitly;
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- Faster evaluation for particular kinds of XPath predicates that involve
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context-position, like: [position() > number] or [number];
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|
||||
- Sort-merge join algorithm implemented for XPath EqualityComparison of
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two nodesets;
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||||
|
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- Deeply nested XPath predicates are evaluated at the very beginning of the
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evaluation phase, to guarantee that evaluation of deeply nested predicates
|
||||
is performed no more than once for each combination of
|
||||
(context-node, context-position, context-size)
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|
||||
library file: Bigloo, Chicken, Gambit: "sxml/ddo-txpath.scm"
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PLT: "ddo-txpath.ss"
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||||
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http://modis.ispras.ru/Lizorkin/ddo.html
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||||
|
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-------------------------------------------------
|
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|
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5. Functional-style modification tool for SXML
|
||||
|
||||
A tool for making functional-style modifications to SXML documents
|
||||
The basics of modification language design was inspired by Patrick Lehti and
|
||||
his data manipulation processor for XML Query Language:
|
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http://www.ipsi.fraunhofer.de/~lehti/
|
||||
However, with functional techniques we can do this better...
|
||||
|
||||
library file: Bigloo, Chicken, Gambit: "sxml/modif.scm"
|
||||
PLT: "modif.ss"
|
||||
|
||||
-------------------------------------------------
|
||||
|
||||
6. STX - Scheme-enabled XSLT processor
|
||||
|
||||
STX is an XML transformation tool based on XSLT and Scheme which combines
|
||||
a processor for most common XSLT stylesheets and a framework for their
|
||||
extension in Scheme and provides an environment for a general-purpose
|
||||
transformation of XML data. It integrates two functional languages - Scheme
|
||||
and XSLT-like transformation language on the basis of the common data model -
|
||||
SXML.
|
||||
|
||||
library file: Bigloo, Chicken, Gambit: "stx/stx-engine.scm"
|
||||
PLT: "stx-engine.ss"
|
||||
|
||||
http://www.pair.com/lisovsky/transform/stx/
|
||||
|
||||
-------------------------------------------------
|
||||
|
||||
7. XPathLink - query language for a set of linked documents
|
||||
|
||||
XLink is a language for describing links between resources using XML attributes
|
||||
and namespaces. XLink provides expressive means for linking information in
|
||||
different XML documents. With XLink, practical XML application data can be
|
||||
expressed as several linked XML documents, rather than a single complicated XML
|
||||
document. Such a design makes it very attractive to have a query language that
|
||||
would inherently recognize XLink links and provide a natural navigation
|
||||
mechanism over them.
|
||||
|
||||
Such a query language has been designed and implemented in Scheme. This
|
||||
language is an extension to XPath with 3 additional axes. The implementation
|
||||
is naturally an extended SXPath. We call this language XPath with XLink
|
||||
support, or XPathLink.
|
||||
|
||||
Additionally, an HTML <A> hyperlink can be considered as a particular case of
|
||||
an XLink link. This observation makes it possible to query HTML documents with
|
||||
XPathLink as well. Neil W. Van Dyke <neil@neilvandyke.org> and his permissive
|
||||
HTML parser HtmlPrag have made this feature possible.
|
||||
|
||||
library file: Bigloo, Chicken, Gambit: "sxml/xlink.scm"
|
||||
PLT: "xpath-context_xlink.ss"
|
||||
|
||||
http://modis.ispras.ru/Lizorkin/xpathlink.html
|
||||
|
||||
|
||||
==========================================================================
|
||||
|
||||
Examples and expected results
|
||||
-----------------------------
|
||||
|
||||
Obtaining an SXML document from XML
|
||||
(sxml:document "http://modis.ispras.ru/Lizorkin/XML/poem.xml")
|
||||
==>
|
||||
(*TOP*
|
||||
(*PI* xml "version='1.0'")
|
||||
(poem
|
||||
(@ (title "The Lovesong of J. Alfred Prufrock") (poet "T. S. Eliot"))
|
||||
(stanza
|
||||
(line "Let us go then, you and I,")
|
||||
(line "When the evening is spread out against the sky")
|
||||
(line "Like a patient etherized upon a table:"))
|
||||
(stanza
|
||||
(line "In the room the women come and go")
|
||||
(line "Talking of Michaelangelo."))))
|
||||
|
||||
Accessing parts of the document with SXPath
|
||||
((sxpath "poem/stanza[2]/line/text()")
|
||||
(sxml:document "http://modis.ispras.ru/Lizorkin/XML/poem.xml"))
|
||||
==>
|
||||
("In the room the women come and go" "Talking of Michaelangelo.")
|
||||
|
||||
Obtaining/querying HTML documents
|
||||
((sxpath "html/head/title")
|
||||
(sxml:document "http://modis.ispras.ru/Lizorkin/index.html"))
|
||||
==>
|
||||
((title "Dmitry Lizorkin homepage"))
|
||||
|
||||
-------------------------------------
|
||||
SXML Transformations
|
||||
|
||||
Transforming the document according to XSLT stylesheet
|
||||
(apply
|
||||
string-append
|
||||
(sxml:clean-feed
|
||||
(stx:transform-dynamic
|
||||
(sxml:add-parents
|
||||
(sxml:document "http://modis.ispras.ru/Lizorkin/XML/poem.xml"))
|
||||
(stx:make-stx-stylesheet
|
||||
(sxml:document
|
||||
"http://modis.ispras.ru/Lizorkin/XML/poem2html.xsl"
|
||||
'((xsl . "http://www.w3.org/1999/XSL/Transform")))))))
|
||||
==>
|
||||
"<html><head><title>The Lovesong of J. Alfred Prufrock</title></head>
|
||||
<body><h1>The Lovesong of J. Alfred Prufrock</h1>
|
||||
<p>Let us go then, you and I,<br/>
|
||||
When the evening is spread out against the sky<br/>
|
||||
Like a patient etherized upon a table:<br/></p>
|
||||
<p>In the room the women come and go<br/>Talking of Michaelangelo.<br/></p>
|
||||
<i>T. S. Eliot</i></body></html>"
|
||||
|
||||
Expressing the same transformation in pre-post-order (requires SSAX package)
|
||||
(pre-post-order
|
||||
(sxml:document "http://modis.ispras.ru/Lizorkin/XML/poem.xml")
|
||||
`((*TOP* *macro* . ,(lambda top (car ((sxpath '(*)) top))))
|
||||
(poem
|
||||
unquote
|
||||
(lambda elem
|
||||
`(html
|
||||
(head
|
||||
(title ,((sxpath "string(@title)") elem)))
|
||||
(body
|
||||
(h1 ,((sxpath "string(@title)") elem))
|
||||
,@((sxpath "node()") elem)
|
||||
(i ,((sxpath "string(@poet)") elem))))))
|
||||
(@ *preorder* . ,(lambda x x))
|
||||
(stanza . ,(lambda (tag . content)
|
||||
`(p ,@(map-union (lambda (x) x) content))))
|
||||
(line . ,(lambda (tag . content) (append content '((br)))))
|
||||
(*text* . ,(lambda (tag text) text))))
|
||||
==>
|
||||
(html
|
||||
(head (title "The Lovesong of J. Alfred Prufrock"))
|
||||
(body
|
||||
(h1 "The Lovesong of J. Alfred Prufrock")
|
||||
(p
|
||||
"Let us go then, you and I,"
|
||||
(br)
|
||||
"When the evening is spread out against the sky"
|
||||
(br)
|
||||
"Like a patient etherized upon a table:"
|
||||
(br))
|
||||
(p "In the room the women come and go" (br)
|
||||
"Talking of Michaelangelo." (br))
|
||||
(i "T. S. Eliot")))
|
||||
|
||||
-------------------------------------
|
||||
XPathLink: a query language with XLink support
|
||||
|
||||
Returning a chapter element that is linked with the first item
|
||||
in the table of contents
|
||||
((sxpath/c "doc/item[1]/traverse::chapter")
|
||||
(xlink:documents "http://modis.ispras.ru/Lizorkin/XML/doc.xml"))
|
||||
==>
|
||||
((chapter (@ (id "chap1"))
|
||||
(title "Abstract")
|
||||
(p "This document describes about XLink Engine...")))
|
||||
|
||||
Traversing between documents with XPathLink
|
||||
((sxpath/c "descendant::a[.='XPathLink']/traverse::html/
|
||||
descendant::blockquote[1]/node()")
|
||||
(xlink:documents "http://modis.ispras.ru/Lizorkin/index.html"))
|
||||
==>
|
||||
((b "Abstract: ")
|
||||
"\r\n"
|
||||
"XPathLink is a query language for XML documents linked with XLink links.\r\n"
|
||||
"XPathLink is based on XPath and extends it with transparent XLink support.\r\n"
|
||||
"The implementation of XPathLink in Scheme is provided.\r\n")
|
||||
|
||||
-------------------------------------
|
||||
SXML Modifications
|
||||
|
||||
Modifying the SXML representation of the document
|
||||
((sxml:modify '("/poem/stanza[2]" move-preceding "preceding-sibling::stanza"))
|
||||
(sxml:document "http://modis.ispras.ru/Lizorkin/XML/poem.xml"))
|
||||
==>
|
||||
(*TOP*
|
||||
(*PI* xml "version='1.0'")
|
||||
(poem
|
||||
(@ (title "The Lovesong of J. Alfred Prufrock") (poet "T. S. Eliot"))
|
||||
(stanza
|
||||
(line "In the room the women come and go")
|
||||
(line "Talking of Michaelangelo."))
|
||||
(stanza
|
||||
(line "Let us go then, you and I,")
|
||||
(line "When the evening is spread out against the sky")
|
||||
(line "Like a patient etherized upon a table:"))))
|
||||
|
||||
-------------------------------------
|
||||
DDO SXPath: the optimized XPath implementation
|
||||
|
||||
Return all text nodes that follow the keyword ``XPointer'' and
|
||||
that are not descendants of the element appendix
|
||||
((ddo:sxpath "//text()[contains(., 'XPointer')]/
|
||||
following::text()[not(./ancestor::appendix)]")
|
||||
(sxml:document "http://modis.ispras.ru/Lizorkin/XML/doc.xml"))
|
||||
==>
|
||||
("XPointer is the fragment identifier of documents having the mime-type..."
|
||||
"Models for using XLink/XPointer "
|
||||
"There are important keywords."
|
||||
"samples"
|
||||
"Conclusion"
|
||||
"Thanks a lot.")
|
||||
|
||||
-------------------------------------
|
||||
Lazy XML processing
|
||||
|
||||
Lazy XML-to-SXML conversion
|
||||
(define doc
|
||||
(lazy:xml->sxml
|
||||
(open-input-resource "http://modis.ispras.ru/Lizorkin/XML/poem.xml")
|
||||
'()))
|
||||
doc
|
||||
==>
|
||||
(*TOP*
|
||||
(*PI* xml "version='1.0'")
|
||||
(poem
|
||||
(@ (title "The Lovesong of J. Alfred Prufrock") (poet "T. S. Eliot"))
|
||||
(stanza (line "Let us go then, you and I,") #<struct:promise>)
|
||||
#<struct:promise>))
|
||||
|
||||
Querying a lazy SXML document, lazyly
|
||||
(define res ((lazy:sxpath "poem/stanza/line[1]") doc))
|
||||
res
|
||||
==>
|
||||
((line "Let us go then, you and I,") #<struct:promise>)
|
||||
|
||||
Obtain the next portion of the result
|
||||
(force (cadr res))
|
||||
==>
|
||||
((line "In the room the women come and go") #<struct:promise>)
|
||||
|
||||
Converting the lazy result to a conventional SXML nodeset
|
||||
(lazy:result->list res)
|
||||
==>
|
||||
((line "Let us go then, you and I,")
|
||||
(line "In the room the women come and go"))
|
||||
SXML Package
|
||||
============
|
||||
|
||||
SXML package contains a collection of tools for processing markup documents
|
||||
(XML, XHTML, HTML) in the form of S-expressions (SXML, SHTML)
|
||||
|
||||
You can find the API documentation in:
|
||||
http://modis.ispras.ru/Lizorkin/Apidoc/index.html
|
||||
|
||||
SXML tools tutorial (under construction):
|
||||
http://modis.ispras.ru/Lizorkin/sxml-tutorial.html
|
||||
|
||||
==========================================================================
|
||||
|
||||
Description of the main high-level package components
|
||||
-----------------------------------------------------
|
||||
|
||||
1. SXML-tools
|
||||
2. SXPath - SXML Query Language
|
||||
3. SXPath with context
|
||||
4. DDO SXPath
|
||||
5. Functional-style modification tool for SXML
|
||||
6. STX - Scheme-enabled XSLT processor
|
||||
7. XPathLink - query language for a set of linked documents
|
||||
|
||||
-------------------------------------------------
|
||||
|
||||
1. SXML-tools
|
||||
|
||||
XML is XML Infoset represented as native Scheme data - S-expressions.
|
||||
Any Scheme programm can manipulate SXML data directly, and DOM-like API is not
|
||||
necessary for SXML/Scheme applications.
|
||||
SXML-tools (former DOMS) is just a set of handy functions which may be
|
||||
convenient for some popular operations on SXML data.
|
||||
|
||||
library file: Bigloo, Chicken, Gambit: "sxml/sxml-tools.scm"
|
||||
PLT: "sxml-tools.ss"
|
||||
|
||||
http://www.pair.com/lisovsky/xml/sxmltools/
|
||||
|
||||
-------------------------------------------------
|
||||
|
||||
2. SXPath - SXML Query Language
|
||||
|
||||
SXPath is a query language for SXML. It treats a location path as a composite
|
||||
query over an XPath tree or its branch. A single step is a combination of a
|
||||
projection, selection or a transitive closure. Multiple steps are combined via
|
||||
join and union operations.
|
||||
|
||||
Lower-level SXPath consists of a set of predicates, filters, selectors and
|
||||
combinators, and higher-level abbreviated SXPath functions which are
|
||||
implemented in terms of lower-level functions.
|
||||
|
||||
Higher level SXPath functions are dealing with XPath expressions which may be
|
||||
represented as a list of steps in the location path ("native" SXPath):
|
||||
(sxpath '(table (tr 3) td @ align))
|
||||
or as a textual representation of XPath expressions which is compatible with
|
||||
W3C XPath recommendation ("textual" SXPath):
|
||||
(sxpath "table/tr[3]/td/@align")
|
||||
|
||||
An arbitrary converter implemented as a Scheme function may be used as a step
|
||||
in location path of "native" SXPath, which makes it extremely powerful and
|
||||
flexible tool. On other hand, a lot of W3C Recommendations such as XSLT,
|
||||
XPointer, XLink depends on a textual XPath expressions.
|
||||
|
||||
It is possible to combine "native" and "textual" location paths and location
|
||||
step functions in one query, constructing an arbitrary XML query far beyond
|
||||
capabilities of XPath. For example, the query
|
||||
(sxpath `("document/chapter[3]" ,relevant-links @ author)
|
||||
makes a use of location step function relevant-links which implements an
|
||||
arbitrary algorithm in Scheme.
|
||||
|
||||
SXPath may be considered as a compiler from abbreviated XPath (extended with
|
||||
native SXPath and location step functions) to SXPath primitives.
|
||||
|
||||
library file: Bigloo, Chicken, Gambit: "sxml/sxpath.scm"
|
||||
PLT: "sxpath.ss"
|
||||
|
||||
http://www.pair.com/lisovsky/query/sxpath/
|
||||
|
||||
-------------------------------------------------
|
||||
|
||||
3. SXPath with context
|
||||
|
||||
SXPath with context provides the effective implementation for XPath reverse
|
||||
axes ("parent::", "ancestor::" and such) on SXML documents.
|
||||
|
||||
The limitation of SXML is the absense of an upward link from a child to its
|
||||
parent, which makes the straightforward evaluation of XPath reverse axes
|
||||
ineffective. The previous approach for evaluating reverse axes in SXPath was
|
||||
searching for a parent from the root of the SXML tree.
|
||||
|
||||
SXPath with context provides the fast reverse axes, which is achieved by
|
||||
storing previously visited ancestors of the context node in the context.
|
||||
With a special static analysis of an XPath expression, only the minimal
|
||||
required number of ancestors is stored in the context on each location step.
|
||||
|
||||
library file: Bigloo, Chicken, Gambit: "sxml/xpath-context.scm"
|
||||
PLT: "xpath-context_xlink.ss"
|
||||
|
||||
-------------------------------------------------
|
||||
|
||||
4. DDO SXPath
|
||||
|
||||
The optimized SXPath that implements distinct document order (DDO) of the
|
||||
nodeset produced.
|
||||
|
||||
Unlike conventional SXPath and SXPath with context, DDO SXPath guarantees that
|
||||
the execution time is at worst polynomial of the XPath expression size and of
|
||||
the SXML document size.
|
||||
|
||||
The API of DDO SXPath is compatible of that in conventional SXPath. The main
|
||||
following kinds of optimization methods are designed and implemented in DDO
|
||||
SXPath:
|
||||
|
||||
- All XPath axes are implemented to keep a nodeset in distinct document
|
||||
order (DDO). An axis can now be considered as a converter:
|
||||
nodeset_in_DDO --> nodeset_in_DDO
|
||||
|
||||
- Type inference for XPath expressions allows determining whether a
|
||||
predicate involves context-position implicitly;
|
||||
|
||||
- Faster evaluation for particular kinds of XPath predicates that involve
|
||||
context-position, like: [position() > number] or [number];
|
||||
|
||||
- Sort-merge join algorithm implemented for XPath EqualityComparison of
|
||||
two nodesets;
|
||||
|
||||
- Deeply nested XPath predicates are evaluated at the very beginning of the
|
||||
evaluation phase, to guarantee that evaluation of deeply nested predicates
|
||||
is performed no more than once for each combination of
|
||||
(context-node, context-position, context-size)
|
||||
|
||||
library file: Bigloo, Chicken, Gambit: "sxml/ddo-txpath.scm"
|
||||
PLT: "ddo-txpath.ss"
|
||||
|
||||
http://modis.ispras.ru/Lizorkin/ddo.html
|
||||
|
||||
-------------------------------------------------
|
||||
|
||||
5. Functional-style modification tool for SXML
|
||||
|
||||
A tool for making functional-style modifications to SXML documents
|
||||
The basics of modification language design was inspired by Patrick Lehti and
|
||||
his data manipulation processor for XML Query Language:
|
||||
http://www.ipsi.fraunhofer.de/~lehti/
|
||||
However, with functional techniques we can do this better...
|
||||
|
||||
library file: Bigloo, Chicken, Gambit: "sxml/modif.scm"
|
||||
PLT: "modif.ss"
|
||||
|
||||
-------------------------------------------------
|
||||
|
||||
6. STX - Scheme-enabled XSLT processor
|
||||
|
||||
STX is an XML transformation tool based on XSLT and Scheme which combines
|
||||
a processor for most common XSLT stylesheets and a framework for their
|
||||
extension in Scheme and provides an environment for a general-purpose
|
||||
transformation of XML data. It integrates two functional languages - Scheme
|
||||
and XSLT-like transformation language on the basis of the common data model -
|
||||
SXML.
|
||||
|
||||
library file: Bigloo, Chicken, Gambit: "stx/stx-engine.scm"
|
||||
PLT: "stx-engine.ss"
|
||||
|
||||
http://www.pair.com/lisovsky/transform/stx/
|
||||
|
||||
-------------------------------------------------
|
||||
|
||||
7. XPathLink - query language for a set of linked documents
|
||||
|
||||
XLink is a language for describing links between resources using XML attributes
|
||||
and namespaces. XLink provides expressive means for linking information in
|
||||
different XML documents. With XLink, practical XML application data can be
|
||||
expressed as several linked XML documents, rather than a single complicated XML
|
||||
document. Such a design makes it very attractive to have a query language that
|
||||
would inherently recognize XLink links and provide a natural navigation
|
||||
mechanism over them.
|
||||
|
||||
Such a query language has been designed and implemented in Scheme. This
|
||||
language is an extension to XPath with 3 additional axes. The implementation
|
||||
is naturally an extended SXPath. We call this language XPath with XLink
|
||||
support, or XPathLink.
|
||||
|
||||
Additionally, an HTML <A> hyperlink can be considered as a particular case of
|
||||
an XLink link. This observation makes it possible to query HTML documents with
|
||||
XPathLink as well. Neil W. Van Dyke <neil@neilvandyke.org> and his permissive
|
||||
HTML parser HtmlPrag have made this feature possible.
|
||||
|
||||
library file: Bigloo, Chicken, Gambit: "sxml/xlink.scm"
|
||||
PLT: "xpath-context_xlink.ss"
|
||||
|
||||
http://modis.ispras.ru/Lizorkin/xpathlink.html
|
||||
|
||||
|
||||
==========================================================================
|
||||
|
||||
Examples and expected results
|
||||
-----------------------------
|
||||
|
||||
Obtaining an SXML document from XML
|
||||
(sxml:document "http://modis.ispras.ru/Lizorkin/XML/poem.xml")
|
||||
==>
|
||||
(*TOP*
|
||||
(*PI* xml "version='1.0'")
|
||||
(poem
|
||||
(@ (title "The Lovesong of J. Alfred Prufrock") (poet "T. S. Eliot"))
|
||||
(stanza
|
||||
(line "Let us go then, you and I,")
|
||||
(line "When the evening is spread out against the sky")
|
||||
(line "Like a patient etherized upon a table:"))
|
||||
(stanza
|
||||
(line "In the room the women come and go")
|
||||
(line "Talking of Michaelangelo."))))
|
||||
|
||||
Accessing parts of the document with SXPath
|
||||
((sxpath "poem/stanza[2]/line/text()")
|
||||
(sxml:document "http://modis.ispras.ru/Lizorkin/XML/poem.xml"))
|
||||
==>
|
||||
("In the room the women come and go" "Talking of Michaelangelo.")
|
||||
|
||||
Obtaining/querying HTML documents
|
||||
((sxpath "html/head/title")
|
||||
(sxml:document "http://modis.ispras.ru/Lizorkin/index.html"))
|
||||
==>
|
||||
((title "Dmitry Lizorkin homepage"))
|
||||
|
||||
-------------------------------------
|
||||
SXML Transformations
|
||||
|
||||
Transforming the document according to XSLT stylesheet
|
||||
(apply
|
||||
string-append
|
||||
(sxml:clean-feed
|
||||
(stx:transform-dynamic
|
||||
(sxml:add-parents
|
||||
(sxml:document "http://modis.ispras.ru/Lizorkin/XML/poem.xml"))
|
||||
(stx:make-stx-stylesheet
|
||||
(sxml:document
|
||||
"http://modis.ispras.ru/Lizorkin/XML/poem2html.xsl"
|
||||
'((xsl . "http://www.w3.org/1999/XSL/Transform")))))))
|
||||
==>
|
||||
"<html><head><title>The Lovesong of J. Alfred Prufrock</title></head>
|
||||
<body><h1>The Lovesong of J. Alfred Prufrock</h1>
|
||||
<p>Let us go then, you and I,<br/>
|
||||
When the evening is spread out against the sky<br/>
|
||||
Like a patient etherized upon a table:<br/></p>
|
||||
<p>In the room the women come and go<br/>Talking of Michaelangelo.<br/></p>
|
||||
<i>T. S. Eliot</i></body></html>"
|
||||
|
||||
Expressing the same transformation in pre-post-order (requires SSAX package)
|
||||
(pre-post-order
|
||||
(sxml:document "http://modis.ispras.ru/Lizorkin/XML/poem.xml")
|
||||
`((*TOP* *macro* . ,(lambda top (car ((sxpath '(*)) top))))
|
||||
(poem
|
||||
unquote
|
||||
(lambda elem
|
||||
`(html
|
||||
(head
|
||||
(title ,((sxpath "string(@title)") elem)))
|
||||
(body
|
||||
(h1 ,((sxpath "string(@title)") elem))
|
||||
,@((sxpath "node()") elem)
|
||||
(i ,((sxpath "string(@poet)") elem))))))
|
||||
(@ *preorder* . ,(lambda x x))
|
||||
(stanza . ,(lambda (tag . content)
|
||||
`(p ,@(map-union (lambda (x) x) content))))
|
||||
(line . ,(lambda (tag . content) (append content '((br)))))
|
||||
(*text* . ,(lambda (tag text) text))))
|
||||
==>
|
||||
(html
|
||||
(head (title "The Lovesong of J. Alfred Prufrock"))
|
||||
(body
|
||||
(h1 "The Lovesong of J. Alfred Prufrock")
|
||||
(p
|
||||
"Let us go then, you and I,"
|
||||
(br)
|
||||
"When the evening is spread out against the sky"
|
||||
(br)
|
||||
"Like a patient etherized upon a table:"
|
||||
(br))
|
||||
(p "In the room the women come and go" (br)
|
||||
"Talking of Michaelangelo." (br))
|
||||
(i "T. S. Eliot")))
|
||||
|
||||
-------------------------------------
|
||||
XPathLink: a query language with XLink support
|
||||
|
||||
Returning a chapter element that is linked with the first item
|
||||
in the table of contents
|
||||
((sxpath/c "doc/item[1]/traverse::chapter")
|
||||
(xlink:documents "http://modis.ispras.ru/Lizorkin/XML/doc.xml"))
|
||||
==>
|
||||
((chapter (@ (id "chap1"))
|
||||
(title "Abstract")
|
||||
(p "This document describes about XLink Engine...")))
|
||||
|
||||
Traversing between documents with XPathLink
|
||||
((sxpath/c "descendant::a[.='XPathLink']/traverse::html/
|
||||
descendant::blockquote[1]/node()")
|
||||
(xlink:documents "http://modis.ispras.ru/Lizorkin/index.html"))
|
||||
==>
|
||||
((b "Abstract: ")
|
||||
"\r\n"
|
||||
"XPathLink is a query language for XML documents linked with XLink links.\r\n"
|
||||
"XPathLink is based on XPath and extends it with transparent XLink support.\r\n"
|
||||
"The implementation of XPathLink in Scheme is provided.\r\n")
|
||||
|
||||
-------------------------------------
|
||||
SXML Modifications
|
||||
|
||||
Modifying the SXML representation of the document
|
||||
((sxml:modify '("/poem/stanza[2]" move-preceding "preceding-sibling::stanza"))
|
||||
(sxml:document "http://modis.ispras.ru/Lizorkin/XML/poem.xml"))
|
||||
==>
|
||||
(*TOP*
|
||||
(*PI* xml "version='1.0'")
|
||||
(poem
|
||||
(@ (title "The Lovesong of J. Alfred Prufrock") (poet "T. S. Eliot"))
|
||||
(stanza
|
||||
(line "In the room the women come and go")
|
||||
(line "Talking of Michaelangelo."))
|
||||
(stanza
|
||||
(line "Let us go then, you and I,")
|
||||
(line "When the evening is spread out against the sky")
|
||||
(line "Like a patient etherized upon a table:"))))
|
||||
|
||||
-------------------------------------
|
||||
DDO SXPath: the optimized XPath implementation
|
||||
|
||||
Return all text nodes that follow the keyword ``XPointer'' and
|
||||
that are not descendants of the element appendix
|
||||
((ddo:sxpath "//text()[contains(., 'XPointer')]/
|
||||
following::text()[not(./ancestor::appendix)]")
|
||||
(sxml:document "http://modis.ispras.ru/Lizorkin/XML/doc.xml"))
|
||||
==>
|
||||
("XPointer is the fragment identifier of documents having the mime-type..."
|
||||
"Models for using XLink/XPointer "
|
||||
"There are important keywords."
|
||||
"samples"
|
||||
"Conclusion"
|
||||
"Thanks a lot.")
|
||||
|
||||
-------------------------------------
|
||||
Lazy XML processing
|
||||
|
||||
Lazy XML-to-SXML conversion
|
||||
(define doc
|
||||
(lazy:xml->sxml
|
||||
(open-input-resource "http://modis.ispras.ru/Lizorkin/XML/poem.xml")
|
||||
'()))
|
||||
doc
|
||||
==>
|
||||
(*TOP*
|
||||
(*PI* xml "version='1.0'")
|
||||
(poem
|
||||
(@ (title "The Lovesong of J. Alfred Prufrock") (poet "T. S. Eliot"))
|
||||
(stanza (line "Let us go then, you and I,") #<struct:promise>)
|
||||
#<struct:promise>))
|
||||
|
||||
Querying a lazy SXML document, lazyly
|
||||
(define res ((lazy:sxpath "poem/stanza/line[1]") doc))
|
||||
res
|
||||
==>
|
||||
((line "Let us go then, you and I,") #<struct:promise>)
|
||||
|
||||
Obtain the next portion of the result
|
||||
(force (cadr res))
|
||||
==>
|
||||
((line "In the room the women come and go") #<struct:promise>)
|
||||
|
||||
Converting the lazy result to a conventional SXML nodeset
|
||||
(lazy:result->list res)
|
||||
==>
|
||||
((line "Let us go then, you and I,")
|
||||
(line "In the room the women come and go"))
|
||||
|
|
|
|||
|
|
@ -1,10 +1,10 @@
|
|||
(module info (lib "infotab.ss" "setup")
|
||||
(define name "sxml")
|
||||
(define blurb
|
||||
(list "Collection of tools for processing markup documents "
|
||||
"in the form of S-expressions"))
|
||||
(define primary-file "sxml.ss")
|
||||
(define doc.txt "doc.txt")
|
||||
(define homepage "http://modis.ispras.ru/Lizorkin/sxml-tutorial.html")
|
||||
(define categories '(xml))
|
||||
)
|
||||
(module info (lib "infotab.ss" "setup")
|
||||
(define name "sxml")
|
||||
(define blurb
|
||||
(list "Collection of tools for processing markup documents "
|
||||
"in the form of S-expressions"))
|
||||
(define primary-file "sxml.ss")
|
||||
(define doc.txt "doc.txt")
|
||||
(define homepage "http://modis.ispras.ru/Lizorkin/sxml-tutorial.html")
|
||||
(define categories '(xml))
|
||||
)
|
||||
|
|
|
|||
Loading…
Reference in New Issue
Block a user