XSH2 acts as a command interpreter. Individual commands must be separated with a semicolon. In the interactive shell, backslash may be used at the end of a line to indicate that a command continues on the next line. Output redirection can be used to pipe output of some XSH command to some external program, or to capture the output to a variable. See Redirection for more info. XSH2 command help provides a complete reference, instantly from the command-line: help command gives a list of all XSH2 commands. help type gives a list of all argument types. help topic followed by documentation chapter gives more information on a given topic. help toc displays the table of contents.

XSH2 is designed as an environment for querying and manipulating XML and HTML documents. Use open or create commands to load an XML or HTML document from a local file, external URL (such as http:// or ftp://), string or pipe. XSH2 can optionally validate the document during parse process (see validation and load-ext-dtd). Parsed documents are stored in memory as DOM trees, that can be navigated and manipulated with XSH2 commands and XPath language, whose names and syntax make working with the DOM tree a flavor of working in a UNIX filesystem. A parsed document is usually stored in a variable. XSH2 shares variables with the XPath engine, so if e.g. $doc is a XSH2 variable holding a document (or, more generally any node-set), then $doc//section/title is an XPath expression selecting all title subelements of all section elements within the (sub)tree of $doc. Although XSH2 is able to parse remote documents via http:// or ftp://, it is only able to save them locally. To upload a document to a remote server (e.g. using FTP) or to store it into a database, use save command with a --pipe parameter, in connection with an external program able to store its standard input (XML) to the desired location. You can also use similar parameter with open in order to parse documents from standard output of some external program. xsh> save --pipe "ssh my.remote.org 'cat > test.xml'" $doc

backups turn on backup file creation catalog use a catalog file during all parsing processes switch-to-new-documents set on/off changing current document to newly open/created files clone clone a given document close close document (without saving) create make a new document from a given XML fragment document specifying documents filename specifying filenames documents display a list of open documents index index a static document for faster XPath lookup nobackups turn off backup file creation nodename specifying names of DOM nodes open load an XML, HTML, or Docbook SGML document from a file, pipe or URI process-xinclude load and insert XInclude sections save save a document as XML or HTML set_filename change filename or URL associated with a document stream process selected elements from an XML stream (EXPERIMENTAL) subroutine name of a sub-routine $variable

With XSH2, it is possible to browse a document tree (XML data represented as a DOM-tree) as if it was a local filesystem, except that XPath expressions are used instead of ordinary directory paths. To mimic the filesystem navigation as closely as possible, XSH2 contains several commands named by analogy of UNIX filesystem commands, such as cd, ls and pwd. The current position in the document tree is called the current node. Current node's XPath may be queried with pwd command. In the interactive shell, current node is also displayed in the command line prompt. (Since there may be multiple document trees open at the same time, XSH2 tries to locate a variable holding the current document and use it to fully qualify current node's XPath in the XSH2 prompt.) Remember, that beside cd command, current node (and document) is also silently changed by open command, create command and temporarily also by the node-list variant of the foreach loop without a loop variable. XPath expressions are always evaluated in context of the current node. Different documents can be accessed through variables: $doc/foo[1]/bar. $scratch:/> $docA := open "testA.xml" $docA/> $docB := open "testB.xml" $docB/> pwd / $docB/> cd $docA/article/chapter[title='Conclusion'] $docA/article/chapter[5]> pwd /article/chapter[5] $docA/article/chapter[5]> cd previous-sibling::chapter $docA/article/chapter[4]> cd .. $docA/article> cd $docB $docB:/> ls <?xml version="1.0" encoding="utf-8"?> <article>...</article>

canonical serialize nodes as to canonical XML cd change current context node fold mark elements to be folded by list command ls list a given part of a document as XML locate show a given node location (as a canonical XPath) pwd show current context node location (as a canonical XPath) register-function define XPath extension function (EXPERIMENTAL) unfold unfold elements folded with fold command unregister-function undefine extension function (EXPERIMENTAL) xpath XPath expression

XSH2 not only provides ways to browse and inspect the DOM tree but also many commands to modify its content by various operations, such as copying, moving, and deleting its nodes as well as creating completely new nodes or XML fragments and attaching them to it. It is quite easy to learn these commands since their names or aliases mimic their well-known filesystem analogies. On the other hand, many of these commands have two versions one of which is prefixed with a letter "x". This "x" stands for "cross", thus e.g. xcopy should be read as "cross copy". Let's explain the difference on the example of xcopy. In a copy operation, you have to specify what nodes are to be copied and where to, in other words, you have to specify the source and the target. XSH2 is very much XPath-based so, XPath is used here to specify both of them. However, there might be more than one node that satisfies an XPath expression. So, the rule of thumb is that the "cross" variant of a command places one and every of the source nodes to the location of one and every destination node, while the plain variant works one-by-one, placing the first source node to the first destination, the second source node to the second destination, and so on (as long as there are both source nodes and destinations left). $scratch/> $a := create "<X><A/><Y/><A/></X>"; $a/> $b := create "<X><B/><C/><B/><C/><B/></X>"; $b/> xcopy $a//A replace $b//B; $b/> copy $b//C before $a//A; $b/> ls $a; <?xml version="1.0" encoding="utf-8"?> <X><C/><A/><Y/><C/><A/></X> $b/> ls $b; <?xml version="1.0" encoding="utf-8"?> <X><A/><A/><C/><A/><A/><C/><A/><A/></X> As already indicated by the example, another issue of tree modification is the way in which the destination node determines the target location. Should the source node be placed before, after, or somewhere among the children of the resulting node? Or maybe, should it replace it completely? This information has to be given in the location argument that usually precedes the destination XPath. Now, what happens if source and destination nodes are of incompatible types? XSH2 tries to avoid this by implicitly converting between node types when necessary. For example, if a text, comment, and attribute node is copied into, before or after an attribute node, the original value of the attribute is replaced, prepended or appended respectively with the textual content of the source node. Note however, that element nodes are never converted into text, attribute or any other textual node. There are many combinations here, so try yourself and see the results. You may even use some more sophisticated way to convert between node types, as shown in the following example, where an element is first commented out and than again uncommented. Note, that the particular approach used for resurrecting the commented XML material works only for well-balanced chunks of XML. $doc := create <<EOF; <?xml version='1.0'?> <book> <chapter> <title>Intro</title> </chapter> <chapter> <title>Rest</title> </chapter> </book> EOF # comment out the first chapter ls //chapter[1] |> $chapter_xml; insert comment $chapter_xml replace //chapter[1]; ls / 0; # OUTPUT: <?xml version="1.0"?> <book> <!-- <chapter> <title>Intro</title> </chapter> --> <chapter> <title>Rest</title> </chapter> </book> # un-comment the chapter $comment = string(//comment()[1]); insert chunk $comment replace //comment()[1]; ls / 0; # OUTPUT: <?xml version="1.0"?> <book> <chapter> <title>Intro</title> </chapter> <chapter> <title>Rest</title> </chapter> </book>

change-ns-prefix change namespace prefix (EXPERIMENTAL) change-ns-uri change namespace URI (EXPERIMENTAL) clone clone a given document copy copy nodes (in the one-to-one mode) declare-ns create a special attribute declaring an XML namespace (EXPERIMENTAL) edit Edit parts of a XML document in a text editor. edit-string Edit a string or variable in a text editor. expression expression argument type hash index selected nodes by some key value insert create a node in on a given target location location relative destination specification (such as after, before, etc.) map transform node value/data using Perl or XPath expression move move nodes (in the one-to-one mode) node-type node type specification (such as element, attribute, etc.) normalize normalizes adjacent textnodes process-xinclude load and insert XInclude sections remove remove given nodes rename quickly rename nodes with in-line Perl code set create or modify document content (EXPERIMENTAL) set-dtd set document's DTD declaration set-enc set document's charset (encoding) set-ns set namespace of the current node (EXPERIMENTAL) set-standalone set document's standalone flag sort sort a given node-list by given criteria strip-whitespace strip leading and trailing whitespace wrap wrap given nodes into elements wrap-span wrap spans of nodes into elements xcopy copy nodes (in the all-to-every mode) xinsert create nodes on all target locations xmove move nodes (in the all-to-every mode) xpath XPath expression xslt compile a XSLT stylesheet and/or transform a document with XSLT xupdate apply XUpdate commands on a document

As almost every scripting language, XSH2 supports subroutines, various conditional statements, loops and even exceptions.

command-or-block single XSH2 command or a block of XSH2 commands call indirect call to a user-defined routine (macro) def sub-routine declaration do execute a given block of commands eval evaluate given expression as XSH commands exit exit XSH2 shell foreach loop iterating over a node-list or a perl array if if statement ifinclude conditionally include another XSH2 source in current position include include another XSH2 source in current position iterate iterate a block over current subtree last immediately exit an enclosing loop next start the next iteration of an enclosing loop prev restart an iteration on a previous node redo restart the innermost enclosing loop block return return from a subroutine run-mode switch into normal execution mode (quit test-mode) stream process selected elements from an XML stream (EXPERIMENTAL) test-mode do not execute any command, only check the syntax throw throw an exception try try/catch statement undef undefine sub-routine or variable unless negated if statement while simple while loop

Beside the possibility to browse the DOM tree and list some parts of it (as described in Navigation), XSH2 provides commands to obtain other information related to open documents as well as the XSH2 interpreter itself. These commands are listed bellow.

apropos search the documentation canonical serialize nodes as to canonical XML count calculate a expression and enumerate node-lists doc-info displays various information about a document get calculate a given expression and return the result. documents display a list of open documents help on-line documentation lineno print line-numbers corresponding to matching nodes ls list a given part of a document as XML defs list all user-defined subroutines dtd show document's DTD locate show a given node location (as a canonical XPath) namespaces List namespaces available in a context of a given nodes settings list current settings using XSH2 syntax print print stuff on standard or standard error output enc show document's original character encoding pwd show current context node location (as a canonical XPath) validate validate a document against a DTD, RelaxNG, or XSD schemas variables list global variables version show version information

Namespaces provide a simple method for qualifying element and attribute names in XML documents. Namespaces are represented by a namespace URI but, since the URI can be very long, element and attribute names are associated with a namespace using a namespace prefix (see the W3C recommendation for details). In an XML document, a prefix can be associated with a namespace URI using a declaration which takes form of special attribute of the form xmlns:prefix="namespace uri" on an element. The scope of the namespace declaration is then the subtree of the element carrying the special xmlns:prefix attribute (and includes attributes of the element). Moreover, a default namespace can be declared using just xmlns="namespace uri". In that case all unprefixed element names in the scope of such a declaration belong to the namespace. An unprefixed element which is not in scope of a default namespace declaration does not belong to any namespace. It is recommended not to combine namespaced elements and non-namespaced elements in a single document. Note that regardless of default namespace declarations, unprefixed attributes do not belong to any namespace (because they are uniquely determined by their name and the namespace and name of the the element which carries them). XSH2 tries to deal namespace declarations transparently (creating them if necessary when nodes are copied between different documents or scopes of namespace declarations). Most commands which create new elements or attributes provide means to indicate a namespace. In addition, XSH2 provides commands declare-ns, set-ns, change-ns-uri, and change-ns-prefix to directly manipulate XML namespace declarations on the current node. Since XSH2 is heavily XPath-based, it is important to remember that XPath 1.0 maps prefixes to namespaces independently of the declarations in the current document. The mapping is instead provided via so called XPath context. Namespaces can be tested in XPath either using the built-in namespace-uri() function, but it is more convenient to use namespace prefixes associated with namespace URIs in the XPath context. This association is independent of the documents to which the XPath expression is applied and can be established using the command register-namespace. Additional, XSH2 automatically propagates the namespace association in the scope of the current node to the XPath context, so that per-document prefixes in the current scope can also be used. IMPORTANT: XPath 1.0 has no concept of a default namespace. Unprefixed names in XPath only match names which have no namespace. So, if the document uses a default namespace, it is required to associate a non-empty prefix with the default namespace via register-namespace and add that prefix to names in XPath expressions intended to match nodes in the default namespace. open "index.xhtml"; $xhtmlns = "http://www.w3.org/1999/xhtml"; register-namespace x $xhtmlns; wrap --namespace $xhtmlns '<font color="blue">' //x:a[@href]; # or wrap '<x:font color="blue">' //x:a[@href]; In the preceding example we associate the (typically default) namespace of XHTML documents with the prefix x. We than use this prefix to match all links (a elements) in the document. Note that we do not write @x:href to match the @href attribute because unprefixed attributes do not belong to the default namespace. The wrap command is used to create new containing elements for the nodes matched by the XPath expression. We may either specify the namespace of the containing element explicitly, using --namespace option, or implicitly, by using a prefix associated with the namespace in the XPath context. In the latter case, XSH2 chooses a suitable prefix declared for the namespace in the document scope (in this case the default, i.e. no, prefix), adding a new namespace declaration if necessary.

change-ns-prefix change namespace prefix (EXPERIMENTAL) change-ns-uri change namespace URI (EXPERIMENTAL) declare-ns create a special attribute declaring an XML namespace (EXPERIMENTAL) namespaces List namespaces available in a context of a given nodes register-namespace register namespace prefix to use XPath expressions register-xhtml-namespace register a prefix for the XHTML namespace register-xsh-namespace register a prefix for the XSH2 namespace set-ns set namespace of the current node (EXPERIMENTAL) unregister-namespace unregister namespace prefix

XSH2 commands accept arguments of various types, usually expressed as Perl or XPath expressions. Unlike in most languages, individual XSH2 commands may evaluate the same expression differently, usually to enforce a result of a certain type (such as a node-list, a string, a number, a filename, a node name, etc.). See expression and individual argument types for more information.

command-or-block single XSH2 command or a block of XSH2 commands command List of XSH2 commands and their general syntax document specifying documents encoding character encoding (codepage) identifier expression expression argument type filename specifying filenames location relative destination specification (such as after, before, etc.) nodename specifying names of DOM nodes node-type node type specification (such as element, attribute, etc.) perl-code in-line code in Perl programming language subroutine name of a sub-routine $variable xpath XPath expression

In XSH2, like in Perl and XPath, variable names are are prefixed with a dollar sign ($). Variables can contain arbitrary Perl Scalar (string, number, array reference, hash reference or an object reference). XPath objects are transparently mapped to Perl objects via XML::LibXML objects. Values can be assigned to variables either by simple assignments of the form $variable = expression, where the right hand side is an expression, or by command assignments of the form $variable := command, where the right hand side is a XSH2 command, or by capturing the output of some command with a variable redirection of the following form: command |> $variable; XSH2 expressions are evaluated either by XPath engine or by Perl (the latter only happens if the entire expression is enclosed with braces {...}), and both Perl and XPath can access all XSH2 variables transparently (Perl expressions may even assign to them). A simple simple expression consisting of a variable name (e.g. $variable) is always evaluated by the XPath engine and the result is the content of the variable as it appears to the XPath data model. Since in XPath object cannot be void (undefined), XPath engine complains, if the value of the variable is undefined. On the other hand, expressions like {$variable} are evaluated by Perl, which results in the value of the variable as seen by Perl. Variables can also be used as macros for complicated XPath expressions. Any occurrence of a substring of the form ${variable} in an XPath expression is interpolated to the value of $variable (if $variable contains an object rather than a string or number, then the object is cast to string first) before the entire expression is evaluated. So, for example, if ${variable} contains string "chapter[title]" (without the quotes), then the XPath expression //sect1/${variable}/para interpolates to //sect1/chapter[title]/para prior to evaluation. To display the current value of a variable, use either print or (in case of a global variables - the distinction is discussed below) the command variables: xsh> $b="my_document"; xsh> $file="${b}s.xml"; xsh> $f := open $file; xsh> ls //$b[count(descendant::para)>10] xsh> print $b my_document xsh> variables ... $b='my_document'; ... $file='my_documents.xml'; ... Variables can also serve as containers for documents and can be used to store lists of nodes that result from evaluating an XPath expression (a.k.a. XPath node-sets). This is especially useful when a sequence of commands is to be performed on some fixed set of nodes and repetitive evaluation of the same XPath expression would be lengthy. XPath node-sets are represented by XML::LibXML::NodeList Perl objects (which is simply a array reference blessed to the above class, which provides some simple operator overloading). In XPath, by a node-set by definition can only contain a single copy of each node and the nodes within a node-set are processed in the same order as they appear in the XML document. Having XPath node-sets represented by a list gives us the advantage of having the possibility to process the list in a different order than the one implied by the document (which is what happens if a variable containing a node-list is evaluated by Perl rather than XPath), see an example below. xsh> $creatures = //creature[@status='alive'] # process creatures in the document order: xsh> foreach $creature print @name; # process creatures in the reverse document order: xsh> foreach { reverse @$creature } print @name; # append some more nodes to a node-list (using a variant of # a simple assignment) xsh> $creatures += //creature[@status='dead']; # again, we can process creatures in order implied by the document: xsh> foreach $creature print @name; # but we can also process first living and then dead creatures, # since this is how they are listed in $creature xsh> foreach {$creature} print @name; # same as the above is xsh> foreach {@$creature} print @name; XSH2 variables are either globally or lexically scoped. Global variables need not to be declared (they can be directly assigned to), whereas lexical variables must be declared using the command my. Global variable assignment may also be made temporal for the enclosing block, using local. $var1 = "foo"; # a global variable requires no declaration local $var1 $var2 $var3; # localizes global variables $var1 = "bar"; # assignment to a localized variable is temporary local $var4 = "foo"; # localized assignment my $var1 $var $var3; # declares lexical variables my $var1 = "foo"; # lexical variable declaration with assignment Lexical variables are only defined in the scope of current block or subroutine. There is no way to refer to a lexical variable form outside of the block it was declared in, nor from within a nested subroutine call. Of course, lexical variables can be referred to from nested blocks or Perl expressions (where they behave just like Perl's lexical variables). On the other hand, global or localized XSH2 variables are just Perl Scalar variables belonging to the XML::XSH2::Map namespace, which is also the default namespace for any Perl code evaluated from XSH2 (so there's no need to use this prefix explicitly in Perl expressions, unless of course there is a lexical variable in the current scope with the same). Localizing a variable using the local keyword makes all assignments to it occurring in the enclosing block temporary. The variable itself remains global, only its original value is restored at the end of the block that localized it. In all above cases, it is possible to arbitrarily intermix XSH2 and Perl assignments: xsh> ls //chapter[1]/title <title>Introduction</title> xsh> $a=string(//chapter[1]/title) xsh> perl { $b="CHAPTER 1: ".uc($a); } xsh> print $b CHAPTER 1: INTRODUCTION Although all XSH2 variables are in fact Perl Scalars, it is still possible to store Perl Array or Hash value to a XSH2 variable via reference. The following example demonstrates using Perl Hashes to collect and print some simple racial statistics about the population of Middle-Earth: my $races; foreach a:/middle-earth/creature { my $race=string(@race); perl { $races->{$race}++ }; } print "Middle-Earth Population (race/number of creatures)" print { map "$_/$races->{$_}\n" keys(%$races); };

assign variable assignment document specifying documents expression expression argument type local temporarily assign new value to a variable subroutine name of a sub-routine $variable xpath XPath expression

WARNING: XSH2 redirection syntax is not yet finished. It is currently the same as in XSH1 but this may be changed in the future releases. Output redirection can be used to pipe output of some XSH command to some external program, or to capture it to a variable. Redirection of output of more than one XSH command can be achieved using the do command.

The syntax for redirecting the output of a XSH command to an external program, is xsh-command | shell-command ;, where xsh-command is any XSH2 command and shell-command is any command (or code) recognized by the default shell interpreter of the operating system (i.e. on UNIX systems by /bin/sh or /bin/csh, on Windows systems by cmd). The shell command may contain further redirections (as supported by the system shell interpreter), but should not contain semicolons, except when the whole shell command is enclosed in brackets. xsh> ls //something/* | grep foo | wc

The syntax for capturing the output of an XSH command to a variable is xsh-command |> $variable, where xsh-command is any XSH command and $variable is any valid name for a variable. xsh> count //words |> $count

The commands listed below can be used to modify the default behavior of the XML parser or XSH2 itself. Some of the commands switch between two different modes according to a given expression (which is expected to result either in zero or non-zero value). Other commands also working as a flip-flop have their own explicit counterparts (e.g. verbose and quiet or debug and nodebug). This inconsistency is due to historical reasons. The encoding and query-encoding settings allow to specify character encodings of user's input and XSH2's own output. This is particularly useful when you work with UTF-8 encoded documents on a console which only supports 8-bit characters. The settings command displays current settings by means of XSH2 commands. Thus it can not only be used to review current values, but also to store them for future use, e.g. in ~/.xshrc file. xsh> settings | cat > ~/.xshrc

backups turn on backup file creation switch-to-new-documents set on/off changing current document to newly open/created files parser-completes-attributes turn on/off parser's ability to fill default attribute values debug display many annoying debugging messages empty-tags turn on/off serialization of empty tags encoding character encoding (codepage) identifier encoding choose output charset indent turn on/off pretty-printing keep-blanks turn on/off ignorable whitespace preservation load-ext-dtd turn on/off external DTD fetching nobackups turn off backup file creation nodebug turn off debugging messages settings list current settings using XSH2 syntax parser-expands-entities turn on/off parser's tendency to expand entities parser-expands-xinclude turn on/off transparent XInclude insertion by parser pedantic-parser make the parser more pedantic query-encoding declare the charset of XSH2 source files and terminal input quiet turn off many XSH2 messages recovering turn on/off parser's ability to fix broken XML register-function define XPath extension function (EXPERIMENTAL) register-namespace register namespace prefix to use XPath expressions register-xhtml-namespace register a prefix for the XHTML namespace register-xsh-namespace register a prefix for the XSH2 namespace run-mode switch into normal execution mode (quit test-mode) skip-dtd turn on/off serialization of DTD DOCTYPE declaration test-mode do not execute any command, only check the syntax unregister-function undefine extension function (EXPERIMENTAL) unregister-namespace unregister namespace prefix validation turn on/off validation in XML parser verbose make XSH2 print many messages xpath-axis-completion sets TAB completion for axes in xpath expressions in the interactive mode xpath-completion turn on/off TAB completion for xpath expressions in the interactive mode xpath-extensions map predefined XSH2 XPath extension functions to no or other namespace

Along with XPath, Perl is one of two XSH2 expression languages, and borrows XSH2 its great expressive power. Perl is a language optimized for scanning arbitrary text files, extracting information from those text files, and printing reports based on that information. It has built-in regular expressions and powerful yet easy to learn data structures (scalars, arrays, hash tables). It's also a good language for many system management tasks. XSH2 itself is written in Perl (except for the XML engine, which uses libxml2 library written in C by Daniel Veillard).

Perl expressions or blocks of code can either be used as arguments to any XSH2 command. One of them is perl command which simply evaluates the given Perl block. Other commands, such as map, even require Perl expression argument and allow quickly change DOM node content. Perl expressions may also provide lists of strings to iterate over with a foreach loop, or serve as conditions for if, unless, and while statements. To prevent conflict between XSH2 internals and the evaluated Perl code, XSH2 runs such code in the context of a special namespace XML::XSH2::Map. As described in the section Variables, XSH2 string variables may be accessed and possibly assigned from Perl code in the most obvious way, since they actually are Perl variables defined in the XML::XSH2::Map namespace. The interaction between XSH2 and Perl actually works the other way round as well, so that you may call back XSH2 from the evaluated Perl code. For this, Perl function xsh is defined in the XML::XSH2::Map namespace. All parameters passed to this function are interpreted as XSH2 commands. Moreover, the following Perl helper functions are defined: xsh(string,....) - evaluates given string(s) as XSH2 commands. call(name) - call a given XSH2 subroutine. count(string) - evaluates given string as an XPath expression and returns either literal value of the result (in case of boolean, string and float result type) or number of nodes in a returned node-set. literal(string|object) - if passed a string, evaluates it as a XSH2 expression and returns the literal value of the result; if passed an object, returns literal value of the object. For example, literal('$doc/expression') returns the same value as count('string($doc/expression)'). serialize(string|object) - if passed a string, it first evaluates the string as a XSH2 expression to obtain a node-list object. Then it serializes the object into XML. The resulting string is equal to the output of the XSH2 command ls applied on the same expression or object expression only without indentation and folding. type(string|object) - if passed a string, it first evaluates the string as XSH2 expression to obtain a node-list object. It returns a list of strings representing the types of nodes in the node-list (ordered in the canonical document order). The returned type strings are: element, attribute, text, cdata, pi, entity_reference, document, chunk, comment, namespace, unknown. nodelist(string|object,...) - converts its arguments to objects if necessary and returns a node-list consisting of the objects. xpath(string, node?) - evaluates a given string as an XPath expression in the context of a given node and returns the result. echo(string,...) - prints given strings on XSH2 output. Note, that in the interactive mode, XSH2 redirects all output to a specific terminal file handle stored in the variable $OUT. So, if you for example mean to pipe the result to a shell command, you should avoid using STDOUT filehandle directly. You may either use the usual print without a filehandle, use the echo function, or use $OUT as a filehandle. In the following examples we use Perl to populate the Middle-Earth with Hobbits whose names are read from a text file called hobbits.txt, unless there are some Hobbits in Middle-Earth already. unless (//creature[@race='hobbit']) { perl { open my $fh, "hobbits.txt" }; @hobbits=<$file>; close $fh; } foreach { @hobbits } { copy xsh:new-element("creature","name",.,"race","hobbit") into m:/middle-earth/creatures; } } perl { unless (count(//creature[@race='hobbit'])) { open my $file, "hobbits.txt"; foreach (<$file>) { xsh(qq{insert element "<creature name='$_' race='hobbit'>" into m:/middle-earth/creatures}); } close $file; } };

XSH2 allows users to extend the set of XPath functions by providing extension functions written in Perl. This can be achieved using the register-function command. The perl code implementing an extension function works as a usual perl routine accepting its arguments in @_ and returning the result. The following conventions are used: The arguments passed to the perl implementation by the XPath engine are simple scalars for string, boolean and float argument types and XML::LibXML::NodeList objects for node-set argument types. The implementation is responsible for checking the argument number and types. The implementation may use general Perl functions as well as XML::LibXML methods to process the arguments and return the result. Documentation for the XML::LibXML Perl module can be found for example at http://search.cpan.org/~pajas/XML-LibXML/. Extension functions SHOULD NOT MODIFY the document DOM tree. Doing so could not only confuse the XPath engine but possibly even result in an critical error (such as segmentation fault). Calling XSH2 commands from extension function implementations is also dangerous and isn't generally recommended. The extension function implementation must return a single value, which can be of one of the following types: simple scalar (a number or string), XML::LibXML::Boolean object reference (result is a boolean value), XML::LibXML::Literal object reference (result is a string), XML::LibXML::Number object reference (result is a float), XML::LibXML::Node (or derived) object reference (result is a node-set consisting of a single node), or XML::LibXML::NodeList (result is a node-set). For convenience, simple (non-blessed) array references consisting of XML::LibXML::Node objects can also be used for a node-set result instead of a XML::LibXML::NodeList.

In the interactive mode, XSH2 interprets all lines starting with the exclamation mark (!) as shell commands and invokes the system shell to interpret the line (this is to mimic FTP and similar command-line interpreters). xsh> !ls -l -rw-rw-r-- 1 pajas pajas 6355 Mar 14 17:08 Artistic drwxrwxr-x 2 pajas users 128 Sep 1 10:09 CVS -rw-r--r-- 1 pajas pajas 14859 Aug 26 15:19 ChangeLog -rw-r--r-- 1 pajas pajas 2220 Mar 14 17:03 INSTALL -rw-r--r-- 1 pajas pajas 18009 Jul 15 17:35 LICENSE -rw-rw-r-- 1 pajas pajas 417 May 9 15:16 MANIFEST -rw-rw-r-- 1 pajas pajas 126 May 9 15:16 MANIFEST.SKIP -rw-r--r-- 1 pajas pajas 20424 Sep 1 11:04 Makefile -rw-r--r-- 1 pajas pajas 914 Aug 26 14:32 Makefile.PL -rw-r--r-- 1 pajas pajas 1910 Mar 14 17:17 README -rw-r--r-- 1 pajas pajas 438 Aug 27 13:51 TODO drwxrwxr-x 5 pajas users 120 Jun 15 10:35 blib drwxrwxr-x 3 pajas users 1160 Sep 1 10:09 examples drwxrwxr-x 4 pajas users 96 Jun 15 10:35 lib -rw-rw-r-- 1 pajas pajas 0 Sep 1 16:23 pm_to_blib drwxrwxr-x 4 pajas users 584 Sep 1 21:18 src drwxrwxr-x 3 pajas users 136 Sep 1 10:09 t -rw-rw-r-- 1 pajas pajas 50 Jun 16 00:06 test drwxrwxr-x 3 pajas users 496 Sep 1 20:18 tools -rwxr-xr-x 1 pajas pajas 5104 Aug 30 17:08 xsh To invoke a system shell command or program from the non-interactive mode or from a complex XSH2 construction, use the exec command. Since UNIX shell commands are very powerful tool for processing textual data, XSH2 supports direct redirection of XSH2 commands output to system shell command. This is very similarly to the redirection known from UNIX shells, except that here, of course, the first command in the pipe-line colone is an XSH2 command. Since semicolon (;) is used in XSH2 to separate commands, it has to be prefixed with a backslash if it should be used for other purposes. xsh> ls //chapter[5]/para | grep funny | less xsh> ls //chapter[5]/para | find "funny" | more

lcd change system working directory exec execute a shell command expression expression argument type hash index selected nodes by some key value map transform node value/data using Perl or XPath expression perl-code in-line code in Perl programming language perl evaluate in-line Perl code rename quickly rename nodes with in-line Perl code

Like many other shells, XSH2 provides means for customizing the format of its interactive shell prompt. The prompt is displayed according to the content of the variable $PROMPT on which the following substitutions and interpolations are performed (in this order): 1. Prompt-string replacements %% - percent sign %p - XPath location of the current node %P - like %p but without an initial document variable %l - XPath location of the current node with ID-shortcuts %L - like %l but without an initial document variable %n - name of the current node %N - local name of the current node %c - canonical XPath name of the current node %y - type of the current node (element,attribute,...) %i - ID of the current node %d - current document variable %h - the hostname up to the first '.' %H - the hostname %s - XSH shell name (basename of $0) %t - the current time in 24-hour HH:MM:SS format %T - the current time in 12-hour HH:MM:SS format %@ - the current time in 12-hour am/pm format %A - the current time in 24-hour HH:MM format %u - the username of the current user %v - the version of XSH2 (e.g., 2.1.0) %V - the revision number of XML::XSH2::Functions (e.g. 2.40) %w - current working directory (on the local filesystem) %W - basename of %w 2. Variable, XPath and Perl interpolations Substrings of the forms ${variable}, ${{...perl...}} and ${(...xpath...)} are interpolated as in XSH2 expressions. 3. Special character substitution \n - newline character \r - line-feed character \t - tab character \a - bell character \b - backspace character \f - form feed character \e - escape character (\033) \\ - backslash character \nnn - the character corresponding to the octal number nnn (useful for non-printable terminal control characters) The default value of $PROMPT is "%p>". Note that you must escape ${...} interpolators like \${...} if you want them to be evaluated at each prompt rather than at the time of the assignment to $PROMPT. For example: $PROMPT="[${{ chomp($u=`uname`);$u }} \${{ chomp($d=`date`);$d }}] %p>"

This section briefly describes differences between XSH2 and previous XSH 1.x releases. The list should not be considered complete. Some syntax variations or amendments in the semantics of various commands may not be documented in this section, neither are various improvements in the XSH interpreter.

In XSH2, subroutines can be called without a call. They can be redefined and undefined. The command call can still be used, but it's use only makes sense in indirect calls, where subroutine's name is computed from an expression. def foo $param1 $param2 { # param1 and $param2 are lexical (a.k.a. my) ls $param1; echo $param2 } foo (//chapter)[1] (//chapter)[1]/title def inc $param1 { return ($param1 + 1) } $two := inc 1; XSH2 uses variables of the form $variable for all kinds of objects, including node-sets (which, if evaluated as Perl expressions, preserve node order). Node-list variables of XSH 1.x have been deprecated. $var = //foo/bar; # node set $var = "hallo world"; # string $var = xsh:new-element("foo"); # node object $var = { ['a','b','c'] }; # Perl array reference $var = {{ 'a'=>'A', 'b'=>'B' }}; # Perl hash reference XSH2 allows variables to be used in XPath just as they are used in XSLT: $var = //foo/bar; ls //baz[ . = $var[@test=1]/any ] Variable interpolation is still available in XSH2 via ${var}, but it's importance is diminished compared to XSH 1.x, because the XPath engine now evaluates variables directly. Interpolation can still be used for things like "XPath-macros": $filter = "[ . = $var[@test=1]/any ]"; ls //baz${filter}; XSH2 equally supports XPath and Perl expressions (written in braces { ... }). Unfortunately, Perl expressions can't be embedded in XPath expressions, but one can still use variables as an agent: perl { use MIME::Base64 }; my $encoded = { encode_base64('open sesame') } ls //secret-cave[string(password) = $encoded] We can, however, use Perl-only expressions complemented with auto-conversion to do things like: copy { encode_base64('Pe do mellon a minno!') } replace //secret-cave/password/text(); Commands return values (see := assignment, or &{ } expressions). $moved_paras := xmove //para replace .; $chapter := wrap chapter $moved_paras; ls $chapter; # or just ls &{ wrap chapter &{ xmove //para replace . } }; XSH2 deprecates "string" expressions of XSH 1.x. However, for convenience, some XSH2 commands interpret name-like XPath expressions on certain argument positions as strings (mostly commands that expect file-name or node-name arguments): insert element my_document into .; insert text "foo" into my_document; $doc := open my_document; # opens file named "my_document" $doc := open "my_document"; # same $doc := open (my_document); # opens file named "foo" $doc := open string(my_document); # same In XSH2, XML documents have no ID. They are referred to using variables (which fits in well with the unified variable concept): $doc1 := open "foo1.xml"; $doc2 := open "foo2.xml"; ls ($doc1//para|$doc2//para); cd $doc1; ls id('intro'); # finds ID intro in the current document ($doc1) ls xsh:id2($doc2, 'intro'); # finds ID intro in $doc2 XSH2 commands have options and flags instead of many optional (positional) arguments. Options/flags usually have both long forms (like --flag) and equivalent short forms (like :f) (colon is borrowed from Scheme, because dash is reserved for XPath minus). $doc := open --format html "version1.html"; save --file "version2.xml" $doc; ls --fold /; ls :f /; ls --depth 1 /; ls :d 1 /; # all the same: $sorted = sort --key @name --locale --descending //user; $sorted = sort :l:d:k@name //user; $sorted = sort --key @name --compare { use locale; $b cmp $a } //user; validate --relaxng --file "test.rng" $mydoc; validate --public "-//OASIS//DTD DocBook XML V4.1.2//EN" $mydoc; validate --yesno $mydoc; Finally, eval is no longer an alias for perl in XSH2, but instead evaluates strings containing XSH2 commands (so eval $string now practically works like old ugly perl { xsh($string) }). See the documentation for eval for a handy usage example (no more PHP, XSTL and XPathScript :-)).

XSH1: foo = file.xml; or foo = "file.xml"; XSH2: $foo := open file.xml; # file.xml is a bareword in file-name context or $foo := open "file.xml"; # "file.xml" is a XPath string or $foo := open {"file.xml"}; # "file.xml" is a Perl string or $foo = xsh:open("file.xml"); # righthand side is an XPath extension function XSH1: open HTML FILE foo2 = "file.html"; XSH2: $foo2 := open --format html "file.html"; XSH1: foo = file.xml; ls foo:(//bar|//baz); XSH2: $foo := open file.xml; ls ($foo//bar|$foo//baz); XSH1: $family = "Arial"; ls //font[@family="$family"]; # interpolation or ls //font[@family="${family}"]; # interpolation XSH2: $family = "Arial"; ls //font[@family=$family]; # evaluation by XPath engine or ls //font[@family="${family}"]; # interpolation XSH1: insert attribute "foo=bar" into /scratch; XSH2: insert attribute "foo=bar" into /scratch; or copy xsh:new-attribute("foo","bar") into /scratch; XSH1: foreach { glob('*.xml') } { open doc = $__; ... } XSH2: foreach { glob('*.xml') } { my $doc := open .; ... } XSH2: foreach my $filename in { glob('*.xml') } { my $doc := open $filename; ... } XSH1: %list = //player; sort @best_score { $a <=> $b } %list; copy %list into .; XSH2: $list := sort --numeric --key @best_score //player; copy { $list } into .; or copy &{ sort --numeric --key @best_score //player } into .; or (using short options) copy &{ sort :n :k @best_score //player } into .;

apropos [--fulltext] [--regexp] expression Print all help topics containing given expression in their short description. The --fulltext flag forces the search to be performed over the full text of help. --fulltext indicates, that the given expression is a regular expression instead of a literal string.

[assign] $variable = expression[assign] $variable := command[assign] $variable [-= | += | *= | /= | %= | x= | .= | ||= | &&= ] expression[assign] $variable [-:= | +:= | *:= | /:= | %:= | x:= | .:= | ||:= | &&:= ] command Evaluate the expression (= assignment) or command (:= assignment) on the right side of the assignment and store the result in a given variable. Optionally a Perl operator (- subtraction, + addition, * multiplication, / division, % modulo, x repeat string n-times, . concatenation, || logical OR, && logical AND) can precede the assignment, in which case the variable is assigned the result of applying given operator on its previous value and the value of the right side of the assignment. xsh> $a=chapter/title; xsh> $b="hallo world"; xsh> $c={ `uname` }; xsh> ls $a; xsh> $a=5*100 # assign 500 to $a xsh> $a += 20 # add 20 to $a xsh> $a = (($a+5) div 10) xsh> $a={ 5*100 } xsh> $a = { join ';', split //,"hallo" } # assigns "h;a;l;l;o" to $a xsh> $doc := open "file.xml" # open a document xsh> $copies := xcopy //foo into //bar # copy elements and store the copies xsh> $wrappers := wrap "wrapper" $copies # wrap each node from $copies to a new element "wrapper" and store the wrapping elements variables

backups Enable creating backup files on save (default). This command is equivalent to setting the $BACKUPS variable to 1. nobackups

call expression [expression ...] Call a subroutine whose name is computed by evaluating the first argument expression. All other expressions are evaluated too and the results are passed to the subroutine as arguments. This command should only be used if the name of the subroutine isn't known at the compile time. Otherwise it is recommended to use a direct subroutine call of the form: subroutine-name [argument1 argument2 ...] def a $arg { echo "A says" $arg } def b $arg { echo "B says" $arg } a "hallo!"; # call subroutine a b "hallo!"; # call subroutine b call { chr(ord("a")+rand(2)) } "surprise!"; # call a or b randomly def, return

canonical [--comments|:c] [--filter|:f xpath] [expression] This commands prints a canonical XML representing nodes specified by its argument (or current node, if no argument is given). --comments or :c removes comments from the resulting XML. --filter or :f can be used to filter the resulting XML so that it only contains nodes explicitly included in the given node-set. For details see "Canonical XML" or "Exclusive XML Canonicalization" W3C recommendations. ls

catalog filename Make use of a given XML file as a catalog during all parsing processes. Using a catalog may significantly speed up parsing processes if many external resources are loaded into the parsed documents (such as DTDs or XIncludes).

cd [expression] chxpath Evaluate given expression to a node-list and change current context node to the first node in it.

change-ns-prefix expression [expression] This command takes one or two arguments. The first argument is a new prefix and the second, optional, argument is an old namespace prefix. It changes the prefix of a namespace declaration of the context node to the new value. If no old prefix is given, the change applies to a declaration on the context node whose prefix equals to the prefix of the context node, otherwise the command changes the declaration with the given old prefix. The command throws an exception if the new prefix is already taken by some other declaration in the scope. change-ns-uri, set-ns, declare-ns, namespaces

change-ns-uri expression [expression] This command takes one or two arguments. The first argument is a new namespace URI and the second, optional, argument is a namespace prefix. It changes the URI value of a namespace declaration of the context node to the new value. If no prefix is given, the change applies to a declaration on the context node whose prefix equals to the prefix of the context node, otherwise the change applies to a declaration with the given prefix. change-ns-prefix, set-ns, declare-ns, namespaces

$doc := clone document dup Create and return a copy of a given document. Unless switch-to-new-documents configuration flag is turned off, the root node of the new document becomes the current node. Calling this command only makes sense if either switch-to-new-documents is set, or if the result is assigned to a variable or passed to another XSH2 command using the &{...} syntax, since otherwise the newly created copy of the document is automatically garbage-collected and destroyed. open, close, enc, documents

close [document] Close a given document (or, if called with no argument, the current document) by trying to remove all references from XSH2 variables to nodes belonging to the document. If no references to the document are left, the garbage-collector destroys the DOM tree and frees the memory it occupied for later reuse (depending on architecture, this may or may not give the allocated memory back to the system).

copy [--respective|:r] expression location expression$results := copy [--respective|:r] expression location expression cp Copies nodes in the first node-list expression (source nodes) to the destinations determined by the the location directive applied to nodes in the second node-list expression (target nodes). If the source node-list contains more than one node, than N'th node in the source node-list is copied to the location relative to the N'th node in the target node-list. If --respective|:r option is used, then the target node-list expression is evaluated in the context of the source node being copied. Possible values for location are: after, before, into, replace, append and prepend. The first three location directives cause making a copy of the source nodes after, before, and within (as the last child-node) the target nodes, respectively. If replace location directive is used, source node are copied before the respective target nodes and target nodes are removed. The append and prepend location directives allow, depending on the destination node type, either inserting copies of the source nodes as the first or last child nodes of a destination element or appending/prepending destination node data in case of non-element destination nodes. See location argument type for more detail. The command returns a node-list consisting of the copies of all source nodes created by the command. Despite the fact the command is named "copy", nodes resulting from copying the source nodes may pass through certain type conversion before they are inserted at the appointed destinations. This, however, only happens in cases where the types of the source and target nodes are not compatible with the location directive. See location argument type for more detail. Note that XSH2 refuses to create multiple top-level elements using copy, move and similar commands. xsh> copy $a//creature replace $b//living-thing xsh> copy --respective $a//* into . xsh> copy $a//* into $a//*#same as above xcopy, move, xmove, insert, xinsert

count [--quiet|:q] xpath Calculates a given expression expression. If the result is a node-list, print number of nodes in the node-list. If the expression results in a boolean, numeric or literal value, print the value. If --quiet or :q option is used, output is suppressed and the value is returned. get

$doc := create nodename|expression new Returns a new document object. The argument must evaluate either to a valid element name (possibly followed by some attribute declarations) to be used for the document element, or to a well-formed XML string. Unless switch-to-new-documents option is turned off, this command also changes current node to the new document. $scratch/> $t1 := create root $t1> ls $t1 <?xml version="1.0" encoding="utf-8"?> <root/> $t1> $t2 := create "root id='r1'" $t2> ls $t2 <?xml version="1.0" encoding="utf-8"?> <root id="r1"/> $t2> create "<root id='r0'>Just a <b>test</b></root>" /> ls / <?xml version="1.0" encoding="utf-8"?> <root id='r0'>Just a <b>test</b></root> open, clone

debug Turn on debugging messages. This is equivalent to setting $DEBUG variable to 1. nodebug

declare-ns expression expression This command takes one or two arguments: prefix and URI, both evaluated as names. It creates a namespace declaration of the form xmlns:prefix="URI" on the current node. The command produces an error if the prefix is already declared in the scope of the current node with a different namespace URI. set-ns, change-ns-uri, change-ns-prefix, namespaces

def subroutine [$variable ...] command-or-block define Define a new XSH2 sub-routine named subroutine. The subroutine may require zero or more parameters. These are declared as a whitespace-separated list of parametric variables. The body of the subroutine is specified as a command-or-block. A sub-routine can be invoked directly by its name followed by its arguments just as any XSH2 command, or indirectly using the call command followed by an expression evaluating to the routine name and sub-routine arguments. Sub-routine arguments can be arbitrary expressions. These expressions are evaluated prior the sub-routine's code execution and are assigned to the sub-routine's parametric variables in the respective order. The number of parameter variables in a sub-routine definition and the number of arguments in a call to it must match. Calling a sub-routine with less or more arguments than declared is a run-time error. Parametric variables are lexical variables within the sub-routine body as if they were declared with my. Note that a subroutine has to be defined before it is first called (in terms of execution -- depending on the structure of the program, the actual definition of the sub-routine must not necessarily precede all references to it). def l3 $nodes { ls --depth 3 $nodes; # list given nodes upto depth 3 } l3 //chapter; # direct call $subref = 'l3'; call $subref //chapter; # in-direct call def comment $n # nodes to move to comments $mark # maybe some handy mark to recognize such comments { foreach $n { if ( . = ../@* ) { echo "Warning: attribute nodes are not supported!"; } else { echo "Commenting out:"; ls --depth 0 .; add comment concat($mark,xsh:serialize(.)) replace .; } } } def uncomment $n $mark { foreach $n { if (. = ../comment()) { # is this node a comment node local $string = substring-after(.,"$mark"); add chunk $string replace .; } else { echo "Warning: Ignoring non-comment node:"; ls --depth 0 .; } } } # comment out all chapters with no paragraphs comment //chapter[not(para)] "COMMENT-NOPARA"; # uncomment all comments stamped with COMMENT-NOPARA $mark="COMMENT-NOPARA"; uncomment //comment()[starts-with(.,"$mark")] $mark; call, return, my, local

defs List names and parametric variables for all user-defined XSH2 subroutines. def, variables

do command-or-block Execute command-or-block. This command is probably only useful when one wants to redirect output of more than one command. command-or-block

doc-info [document] doc_info In the present implementation, this command displays information provided in the <?xml ...?> declaration of a document: version, encoding, standalone, plus information about level of gzip compression of the original XML file and the original XML file URI. set-enc, set-standalone

documents files, docs Try to identify open documents and list their URIs and variables that contain them. open, close

dtd [document] Print external or internal DTD for a given document. If used without arguments prints DTD of the current document. set-dtd, validate

edit [--editor|:E filename] [--all|:A] [--noindent|:n] [--recover|:r] [--keep-blanks|:k] [--allow-empty|:0] [--no-coment|:q] [--encoding|:e encoding] expression This command may be used to interactively edit parts of a XML document directly in your favorite editor. A given expression is evaluated to a node-list and the first the first resulting node is opened in an external editor as a XML fragment. When the editor exits, the (possibly modified) fragment is parsed and returned to the original document. Unless --no-comment (:q) flag is used, the XML fragment is preceded with a XML comment specifying canonical XPath of the node being edited. The command returns a node-list consisting of nodes that resulted from parsing the individual edits. --editor or :E option may be used to specify external editor command. If not specified, environment variables EDITOR and VISUAL are tried first, then vi editor is used as a fallback. If --all or :A flag is present, all nodes from the node-list are opened in the editor, one at a time. If --recover or :r is specified, the parser tries to recover from possible syntax errors when parsing the resulting XML. --keep-blanks or :b option may be used to force the parser to include ignorable white space. If the result saved by the editor is empty, the interactive XSH2 shell asks user to confirm this was correct. This confirmation can be suppressed using --allow-empty or :0 (zero) options. The --encoding or :e parameter can be used to specify character encoding to use when communicating with the external editor. edit --editor 'emacs -nw' --encoding iso-8859-1 --all //chapter

edit-string [--editor|:E filename] [--encoding|:e encoding] [--allow-empty|:0] expression Evaluating given expression to a string, save it in a temporary file, open the file an external editor as a plain text, and when the editor exits, read and return the result. The --editor (:E) parameter can be used to provide an editor command, whereas --encoding (:e) can be used to specify character encoding used for communication with the editor. If the result is empty, the interactive XSH2 shell asks user for confirmation before returning the result in order to prevent data loss due to some unexpected error. To suppress this feature, use --allow-empty or :0 flag.

empty-tags expression empty_tags If the value of expression is 1 (non-zero), empty tags are serialized as a start-tag/end-tag pair (<foo></foo>). This option affects both ls and save and possibly other commands. Otherwise, they are compacted into a short-tag form (<foo/>). Default value is 0. This command is equivalent to setting the $EMPTY_TAGS variable.

enc [document] Print the original document encoding string. If no document is given, the current document is used. set-enc

encoding encoding Set the default character encoding used for standard (e.g. terminal) output. This doesn't influence the encoding used for saving XML documents. This command is equivalent to setting the $ENCODING variable. query-encoding

eval expression NOTE: This command has very different behavior from XSH1, where it used to be an alias for perl. This command first evaluates a given expression to obtain a string, then evaluates this string as XSH2 code in the current context, returning the return value of the last evaluated command. This command raises an exception if either expression evaluates to invalid XSH2 code or if evaluating the code raises an exception. foreach //inline-xsh eval .;

exec expression [expression ...] system This command executes given expression(s) as a system command and returns the exit code. exec echo hallo world; # prints hallo world exec "echo hallo word" | wc; # counts words in hallo world exec uname; # prints operating system name

exit [expression] quit Exit xsh, optionally with an exit-code resulting from evaluation of a given expression. WARNING: No files are saved on exit.

fold [--depth|:d expression] [expression] This feature is still EXPERIMENTAL and may change in the future! Fold command may be used to mark elements with a xsh:fold attribute from the http://xsh.sourceforge.net/xsh/ namespace. When listing the DOM tree using ls --fold xpath, elements marked in this way are folded to a given depth (default is 0 = fold immediately). The option --depth (:d) may be used to specify the depth at which subtrees of given elements are to be folded. If called without arguments, the command applies to the current element, otherwise the expression is evaluated to the node-list and folding is applied to all elements within this node-list. xsh> fold --depth 1 //chapter xsh> ls --fold //chapter[1] <chapter id="intro" xsh:fold="1"> <title>...</title> <para>...</para> <para>...</para> </chapter> unfold, ls

foreach expression command|command-or-block foreach [my|local] $variable in expression command|command-or-block for Evaluate given expression to a node-list and for each resulting node execute given command or command-or-block. If used without a loop $variable, the loop temporarily sets current node to the node being processed. Otherwise, the processed node is assigned to the loop variable. The expression may be xpath as well as a perl-code. In the latter case, if used without a loop variable, the loop automatically converts Perl objects to nodes. No conversion is performed when a loop variable is used. xsh> foreach //company xmove employee into staff[1]; xsh> foreach my $filename in { glob('*.xml') } { $f := open $filename; do_something $f; }

get expression exp, expr Calculate a given expression and return the value. count

$hash := hash expression expression This command takes two arguments: an expression computing a key from a given node (1st argument) and a node-set (2nd argument). For each node in the node-set, the key value is computed and the node is stored under the given key in the resulting hash. For a given key, the value stored in the hash table is a node-list consisting of all nodes for which the 1st expression evaluated to an object string-wise equal to the key. It is therefore possible to index more than one node under the same key. The XPath function xsh:lookup(varname,key) can be used to retrieve values from hashes in XPath expressions. my $books_by_author := hash concat(author/firstname," ",author/surname) //book; ls { $books_by_author->{'Jack London'} }; ls xsh:lookup('books_by_author','Jack London'); xsh:lookup

help command|argument-type|xsh:xpath-function Print help on a given command, argument type or XPath extension function (use xsh: as a prefix to XPath extensions function names, e.g help xsh:id2).

if expression command if expression command-or-block [ elsif command-or-block ]* [ else command-or-block ] Executes command-or-block if a given expression expression evaluates to a non-emtpty node-list, true boolean-value, non-zero number or non-empty literal. If the first expression fails, then elsif conditions are tested (if any) and the command-or-block corresponding to the first one of them which is true is executed. If none of the conditions is satisfied, an optional else command-or-block is executed. def node_type %n { foreach (%n) { if ( . = self::* ) { # XPath trick to check if . is an element echo 'element'; } elsif ( . = ../@* ) { # XPath trick to check if . is an attribute echo 'attribute'; } elsif ( . = ../processing-instruction() ) { echo 'pi'; } elsif ( . = ../text() ) { echo 'text'; } elsif ( . = ../comment() ) { echo 'comment' } else { # well, this should not happen, but anyway, ... echo 'unknown-type'; } } } if { defined($ENV{HOME}) } lcd { $ENV{HOME} }

ifinclude [--encoding|:e encoding] filename Unless the file filename has already been included using either include of ifinclude, load the file and execute it as a XSH2 script. Use --encoding or :e parameter to specify character encoding used in the included file. include

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