Conformance to standards |

This library is aligned with the Recommendations issued on the 23rd January 2007 for XPath 2.0 and XSLT 2.0. An XSLT processor claiming conformance with theseRecommendations is required to document what choices it makes for features that are listed as implementation-defined.

The library claims conformance to a Basic XSLT processor, and in addition supports the optional features Serialization Feature and Backwards Compatibility Feature.

## Implementation-defined choices

Invocation of the processor
  This is described elsewhere in the documentation starting from Overview. The Base Output URI is equal to the value of `system_id` in `XM_XSLT_TRANSFORMATION_RESULT`, and this is set by whichever creation procedure you use to create the object. See Transformation Result.

  The command-line processor, by default, sets it to stdout:. This URI scheme (defined by the library), has only the one lexical value, so relative URIs are not possible with this default.

Creating new extension instructions and extension functions
  There is no mechanism provided for creating new extension instructions. See Creating extension functions for the mechanism for creating new extension functions.
Recoverable Dynamic Errors
  The decision on whether or not to recover from a recoverable dynamic error is made by the `XM_XSLT_ERROR_LISTENER`. See The Error Listener for more details.
Type Errors
  Type errors are signalled statically whenever possible.
Extension Namespaces
  See Overview.
User-defined Data Elements
  See Extensions.
Collection URIs
  See Collections.
URI References
  The following URI schemes are directly supported by the library for reference by the href attribute of xsl:import and xsl:include:
  - file
  - data
  - stdin
  - string

  The last two schemes are used for reading from the standard input stream and text from Eiffel `STRING`s respectively. They are documented in Resolvers, which also documents how to add additional URI schemes.

  The following additional URI schemes are supported by Gestalt:

  - http
  - https
  - ftp

  For the list of supported media types and treatment of fragment identifiers, see Options This also applies to the document() function.

Limits
  - The maximum number of digits permitted for an xs:decimal value is at least 18, but may be set to any higher value.
  - For dates and times, both positive and negative year values are supported for any value that can be represented by a 32-bit signed integer. The maximum number of fractional second digits is three. Although additional digits will be recognised, values are rounded to 3 digits.
  - For durations, the maximum values for the years, months, days, hours, minutes and seconds components are those that can be represented by a 32-bit signed integer.
  - For xs:yearMonth durations, the greatest durations that can be expressed in months is 13 times the maximum positive number that can be expressed as a 32-bit signed integer.
  - For xs:dayTime durations, the greatest durations that can be expressed in seconds is 24 * 60 * 60 times the maximum positive number that can be expressed as a 32-bit signed integer.
  - For xs:string, xs:hexBinary, xs:base64Binary, xs:QName, xs:anyURI and xs:NOTATION, the maximum length of a value is the maximum positive number that can be expressed as a 32-bit signed integer.
  - The maximum length of a sequence is the maximum positive number that can be expressed as a 32-bit signed integer.
Implicit Timezone
  The implicit timezone is set to the local time zone when a transformer is created.
Numbering sequences
  No additional numbering sequences are defined.
Upper bounds on numbering sequences with xsl:number
  When using Roman Numerals, the maximum number is 3,999.
Languages supported by xsl:number
  The default language is English (en). The library does not have built-in support for any other languages right now, but these can be added by writing a descendant of `XM_XSLT_NUMBERER`, and editing `selected_numberer` of `XM_XSLT_NUMBER_ROUTINES`.

  TODO: there should be a plugin-mechanism for this.

Data-type attribute on xsl:sort
  If the data-type attribute on the xsl:sort instruction has a value other than text or number then error XTDE0030 is issued at run-time.
Defining collation URIs
  There is currently no mechanism for defining collations.
Selecting collations
  The algorithm currently used by xsl:sort for select a collation, given a lang and case-order attribute, is to use the Unicode Code-point collation for English, and to raise an error for any other language.
Date/time formatting
  The default language is English (en). No other languages are currently supported. The default calendar is CE. AD is also supported. The default country is US. The country is currently ignored, and all values are accepted. This will change.

  The following abbreviations are used for the days of the week in English:

  - Sun
  - Mon
  - Tues
  - Weds
  - Thurs
  - Fri
  - Sat
System properties
  The following values are returned for the standard system-properties:
  xsl:version
    2.0
  xsl:vendor
    Gobo

    This is actually configurable, by calling `set_vendor_name` from `XM_XPATH_CONFIGURATION`. For Gestalt, the value is Colin Adams.

  xsl:vendor-url
    http://www.gobosoft.com/

    This is actually configurable, by calling `set_vendor_url` from `XM_XPATH_CONFIGURATION`. For Gestalt, the value is http://gestalt.sourceforge.net/.

  xsl:product-name
    Gexslt

    This is actually configurable, by calling `set_product_name` from `XM_XPATH_CONFIGURATION`. For Gestalt, the value is Gestalt.

  xsl:product-version
    This is equal to the version of the Gobo library. See Gobo news

    This is actually configurable, by calling `set_product_version` from `XM_XPATH_CONFIGURATION`. For Gestalt, the value is the version of Gestalt.

  xsl:is-schema-aware
    no
  xsl:supports-serialization
    yes
  xsl:supports-backwards-compatibility
    yes
  xsl:supports-namespace-axis
    no

  Also, any property in the namespace http://exslt.org/system/environment is treated as the name of an environment variable. If that environemnt variable is set, then it's value is returned.

  Additional system properties in other namespaces may be registered. The standard implementation provides the following properties in the namespace http://www.gobosoft.com/eiffel/gobo/gexslt/extension:

  gexslt:standard-file-collection
    A value of yes indicates collection URIs in the file scheme are supported as documented in Collections.
  gexslt:standard-ftp-collection
    A value of yes indicates collection URIs in the ftp scheme are supported as documented in Collections.
  gexslt:standard-http-collection
    A value of yes indicates collection URIs in the http scheme are supported as documented in Collections.
Destination for xsl:message
  All xsl:message output goes to the standard error stream by default. This is configurable (see API documentation).
Extension function string results
  Extension functions are required to raise an error if they attempt to return a string that contains invalid XML characters. Since any extension functions must be linked into the executable, this effectively means that there will be a different implementation.
External objects
  None.
Final result trees
  See Accessing the Transformation Results for how to access final result trees.

  The following URI schemes are directly supported by the library for the value of the href attribute of the xsl:result-document instruction:

  - file
  - string
  - stdout

  Stdout refers to the standard output stream. The only value permitted for URIs in this scheme is the the string stdout:. String refers to Eiffel `STRING`s.

  The following additional URI schemes are supported by Gestalt:

  - http
  - ftp
  - mailto

  Eiffel programmers may add additional URI schemes. See The Output URI Resolver

  Serialization is to the destination implied by the URI scheme. In the case of string:, these can only be retrieved by an Eiffel program, by accessing `output_destinations` from `XM_XSLT_OUTPUT_URI_RESOLVER`.

Encoding
  The default value for the encoding attribute of xsl:output is UTF-8.
Output versions
  This implementation supports the values 1.0 and 1.1 for the version attribute of xsl:output when the method is xml or xhtml . It supports 4.0 or 4.01 when the method is html.
Byte order mark
  The default value for the byte-order-mark attribute of xsl:output is no when the encoding is UTF-8.
Disabling Output Escaping
  This is not supported.
Normalization forms
  Only NFC, NFKC, NFD and NFKD are supported.