xml2kvp: concatenate multi-valued, split to multi-valued

[ghukill]

Provides keys that will undergo concatenation if multi-valued.

e.g., indexing MARC XML, ignoring ind# and code attributes, you can get the following values for the constructed field marc|record___marc|datafield___@tag=245:

['Poeti contemporanei :', 'Prati, Aleardi, Carducci, Praga, Giacosa /', 'Corrado Corradino.']
Kumāratantram.
['Demarcacion de limites con los Estados Unidos del Brasil,', 'Documentos comp. y tr. por Manuel V. Ballivián ...']
["Pierre Ranson, peintre de fleurs et d'arabesques.", "56 planches accompagnées d'une notice et d'un essai de catalogue de l'oeuvre,", 'par Henri Clouzot.']

These lists are looking at record-by-record, but looking at value-by-value, they are deconstructed. Would be helpful to allow concatenation within field, or copy to.

And/or, this might be a good argument for determing sensible order of field copying. As it would be possible to copy marc|record___marc|datafield___@tag=245 to concat_245 with the concatenation applied to concat_245 after the copy.

[ghukill]

Additionally, split field to multi-valued

[ghukill]

Concatenating values works via two args:

• concat_values_on_all_fields
  • expects string used to join, loops through all fields and joins those that are mutlivalued
  • e.g. --> would convert ['goober','tronic'] to goober --> tronic
• concat_values_on_field
  • expects dictionary of key (after mapping) : string to join on, pairs
  • e.g. {'root___foo___bar':' --> '} would conctenate all values for root__foo__bar with joiner string -->

Proceeding with splitting...

[ghukill]

Done.