====== Advanced Greenstone 2 Formatting Topics ======

===== Displaying Language Names instead of Codes =====

Often documents will have language metadata in two letter codes, such as en, fr, ja, or maybe three letter codes, like eng, fre, ger.

Lets say our documents have two letter language codes, in the dc.Language metadata field. And we want to display this in our search results. We can add //[dc.Language]// to the SearchVList format statement.

If we want to display the name of the language instead of the code, we can use //[format:dc.Language]//.

Internally, //[format:dc.Language]// will get turned into a macro: //_iso639:iso639xx_// where xx is the two letter code. For example, if the language was en, then the macro will be //_iso639:iso639en_//.
These macros are defined in languages.dm in the macros folder.

=== Displaying language names in other languages ===
Greenstone only provides English versions of the language names. You can add macro definitions for other languages into the languages.dm file by copying the rule and adding a language argument. For example:

//_iso639en_ [l=fr] {Anglais}\\
_iso639en_ [l=es] {Inglés}//

=== Using three letter codes ===

Greenstone only provides a mapping for two letter codes. If you are using three letter codes, you can add in new mappings to the languages.dm file in a similar way.

Add for example:

//_iso639eng_ {English}\\
_iso639fre_ {French}//

Alternatively, you can use //_iso639eng_ {_iso639en_}// which will map the three letter code to the two letter code. This is useful if you have defined rules for displaying the codes in different languages.

=== Language codes that are not in Language metadata ===

This formatting trick in Greenstone only works for metadata elements called Language (or with a namespace, e.g. dc.Language). There is a hard coded test for 'Language' in the source code. What can you do if your language codes are in a different metadata element?

This applies too if you have built a classifier on Language metadata. When you are displaying the bookshelf of the classifier, the metadata you are outputting is no longer called //Language//, it is called //Title//. //[format:Title]// will not do the same thing as //[format:Language]//.

When //[format:MetaName]// is processed by the source code, the metadata name (MetaName) is tested. If it is Date, then we output //_format:date_(xxx)// where xxx is the date value. If the metadata name is Language, we output //_iso939:iso639xx_// where xx is the language value.

For all others, we output //_format:MetaName_(xxx)// where MetaName is the metadata name and xxx is the value. We can define this macro to make it use the language code rules. 

In the collection's extra.dm, or in GLI's Collection Specific Macros part of the Format panel, add lines like the following.

This example will turn [format:Title] into a language macro, and can be used for displaying language names in a bookshelf of a classifier built on the language codes.

//package format\\
\\
_Title_ {_iso639:iso639_1__}\\
//

The //_1_// part represents the (first) argument passed in to the macro.