Can't make global regular substitution work

[EmilyGraceSeville7cf]

My code is (Nushell):

let code = '    {
        "copyToClipboardCmd": {
            "type": "string"
        },
        "editPreset": {
            "type": "string"
        },
        "edit": {
            "type": "string"
        },
        "editAtLine": {
            "type": "string"
        },
        "editAtLineAndWait": {
            "type": "string"
        },
        "open": {
            "type": "string"
        },
        "openLink": {
            "type": "string"
        }
    }'
$code | yq -P -o json 'to_entries | map(.value.title = (.key | gsub("(?<x>[A-Z])"; " \(.x)") | ascii_downcase)) | from_entries'

But it doesn't work: Error: 1:41: invalid input text "gsub(\"(?<x>[A-Z]..." is shown. It's not clear what it means: does gsub exist at all (but is undocumented), or there is an error inside regex somewhere? If gsub doesn't exist I suggest improving the error message to state that there is no such function. My goal is to rewrite this jq piece of code:

jq 'to_entries | map(.value.title = (.key | gsub("(?<x>[A-Z])"; " \(.x)") | ascii_downcase)) | from_entries'

[mikefarah]

It's not recognising gsub because that hasn't yet been added to yq - it's a expression lexing error. It's hard to know from lexing error if its a missing function or other bad syntax.

I'm not 100% sure what your expression does - it seems like it makes keys lower case? In which case you could do:

yq 'with_entries(.key |= downcase)' examples/data2.yaml

There is a regex sub function, documented here: https://mikefarah.gitbook.io/yq/operators/string-operators#sub-regex-replacement - though it doesn't work exactly like jq as yq is using the build in regex in go...see the docs for more examples.

[EmilyGraceSeville7cf]

I'm not 100% sure what your expression does - it seems like it makes keys lower case?

It was intended to convert all capital letters to lower case and add space before each of them. blaBla -> bla bla, e.g.