Introduce function to concatenate value to field

[TobiasNx]

Sometimes one has multiple fields that should be concatinated together, often it is the same element. Also sometimes one wants to add the value of an element to an existing field.
paste wont do the trick if one element exists multiple times, also it pasts even if the element does not exist and creating an empty array, copying the value in this array and then join_field is a workaround.

I suggest a concatenate function: concatenate("<sourceElement>", "<targetElememt>",[join_char: "[...]", direction: "[front/back]")

in:

honorificPrefix: Dr.
name: Maxi Muster

fix:
concatenate("honorificPrefix", "name", direction: "front")

out:

honorificPrefix: Dr.
name: Dr. Maxi Muster

If the target element does not exist, then the targetElement would be created.

[blackwinter]

Can you illustrate your edge cases with examples? The given example is equivalent to paste("name", "honorificPrefix", "name").

[TobiasNx]

Case 1:
in:

keyword: dog
keyword: animal
keyword: companion

fix
concatenate("keyword","keywords",join_char:"; ")

out:

keyword: dog
keyword: animal
keyword: companion
keywords: dog; animal; companion

Case 2:
in:
record 1:

pages: 56 S.
additionalMaterial: Illustration
size: 30 cm

record 2:

pages: 5 S.
size: 27 cm

fix:

copy_field("pages","extent")
concatenate("additionalMaterial","extent",join_char:" ; ")
concatenate("size","extent",join_char:" : ")

out:
record 1:

pages: 56 S.
additionalMaterial: Illustration
size: 30 cm
extent: 56 S. : Illustration ; 30 cm

record 2:

pages: 5 S.
size: 27 cm
extent: 5 S. : 27 cm

[blackwinter]

Thanks. Although I'm still not sure that they justify a new method.

Case 1:

copy_field("keyword", "keywords")
join_field("keywords", "; ")

Case 2:

copy_field("pages", "extent")
paste("extent", "extent", "additionalMaterial", join_char: " : ")
paste("extent", "extent", "size", join_char: " ; ")

The latter is certainly more complicated due to the optional clauses. But this could be an option ignore_missing: "true" or something like that (see also #226).

BTW: Your use of separators in the second example is not consistent. The desired output could only be achieved if additionalMaterial and size were concatenated first (with separator ;) and then appended to pages (with separator :).

paste('extent', 'additionalMaterial', 'size', join_char: ' ; ')
paste('extent', 'pages', 'extent', join_char: ' : ')

[TobiasNx]

another case would be simplified:

    set_array("subject[].$last.label")
    set_array("$i.@name")
    copy_field("$i.a","$i.@name.$append")
    copy_field("$i.b","$i.@name.$append")
    copy_field("$i.c","$i.@name.$append")
    copy_field("$i.d","$i.@name.$append")
    join_field("$i.@name")
    copy_field("$i.@name","subject[].$last.label.$append")
    copy_field("$i.x","subject[].$last.label.$append")
    copy_field("$i.y","subject[].$last.label.$append")
    copy_field("$i.z","subject[].$last.label.$append")
    copy_field("$i.v","subject[].$last.label.$append")
    join_field("subject[].$last.label"," / ")

[blackwinter]

What would the simplification with concatenate() look like? Isn't it already rather simple with paste() (save for ignore_missing: "true" if that's what's pivotal here)?

paste("$i.@name", "$i.a", "$i.b", "$i.c", "$i.d")
paste("subject[].$last.label", "$i.@name", "$i.x", "$i.y", "$i.z", "$i.v", join_char: " / ")

To be clear: It's not my intention to dismiss your use cases here. It's just that I'd rather extend an existing function instead of introducing a new one that does almost the same.

[blackwinter]

save for ignore_missing: "true" if that's what's pivotal here

How did we even get to this point? Missing (null) values are already ignored. Your initial remark referred to #226, didn't it?

also it past[e]s even if the element does not exist

[blackwinter]

So paste() needs to learn skip_incomplete: "true" for #226 and flatten: "true" (or recursive: "true"?) for arrays. The only thing remaining would be appending/prepending to an existing field which needs to be explicit with paste() (while also being more flexible).

Would this satisfy your requirements?