LXT

lxt is the L. XSL Templates language. It is designed to present a more “natural” language to programmers, rather than the highly verbose and difficult to comprehend XSLT language.

So, it’s design is to take the Domain-Specific Language LXT and compile that into XSLT, which can then be used for all things that XSLT can be used for.

Grammar

Keywords

Top-level Directives

output: Defines the format of the output document via the given ( param => "value" ) map.

Variables and Parameters

var: define an xsl:variable with the given value.
param: define an xsl:param that defaults to the given value, but can be overridden by arguments.

Subfunctions and Templates

sub: define a named xsl:template: sub name ( param => <default> ) body.
call: call a named xsl:template: call name ( argument => <value> ).
template: define an anonymous xsl:template used for template matching.
apply-templates: automatically match and apply matching templates.

Control flow:

when/otherwise: these are chained together to construct an xsl:choose block. An otherwise always terminates the xsl:choose block.
if: constructs a simple if-then xsl:if block from the given XPath and expression.
foreach/for-each: constructs a xsl:for-each to loop over a given XPath selector, executing the given body.

HTML/XHTML sugar

tag: constructs an xsl:element with the given name and body.
attribs: constructs a map of key => value attributes for the current block using xsl:attribute.
div: constructs the XSL appropriate to output a <div class="name">body</div> with the given class name, and body.
span: constructs the XSL appropriate to output a <span class="name">body</span> with the given class name, and body.

Strings

There are three kinds of strings: "double quote", "single quote", and back-tick quotes.

There is currently no distinction between them, except that each quote format does not need to escape any of the others. (NOTE: This will likely change, as the language is made more strict.)

Most times, when a quoted string is included, it will automatically put into an xsl:text block.

XPath statements

XPath statements are:

$variable-identifier
@attribute-identifier
<./namespace::simple/*/xpath/statements/@identifier>
<{ full < extended/xpath[statements = 0] }>

Any abitrary XPath statement can be written by surrounding it with angled brackets around braces: <{xpath}>.

If an XPath statement only consists of selectors, it can be shorthanded by surrounding it by only angled brackets: <xpath>

If an XPath statement only consists of a variable reference, it can be used directly: $variable.

If an XPath statement only consists of an attribute reference, it can be used directly: @attribute.

The common use of an XPath statement of just ., it requires being placed in angled brackets: <.>

In most cases, where an XPath appears as an expression, it is automatically turned into a xsl:value-of block.

Blocks

A block is any group of expressions between a block-start, and a corresponding block-end. The three kinds are: ( … ), [ … ] and { … }.

Some keywords have different semantics according to which specific block is used, though often any pair of block-start and block-end can be used to define most blocks. (NOTE: This will likely change, as the language is made more strict.)

Example: The sub keyword, will interpret a ( block ) as a map of param names to default values. The other two block types will be interpreted as expressions to define the body of the subfunction.

puellanivis / lxt

LXT