I have written a new script for csv file export, which writes lines to a %Library.File file based on a SQL query.

The code is simplified into the following as 

try {
    // set up file as %Libary.File
    set f = ##class(%Library.File).%New()
    set f.Name = "export.csv"
    if (##class(%File).Exists(f.Name)) { $$$ThrowOnError(##class(%File).Delete(f.Name)) }
    $$$ThrowOnError(f.Open("WUN"))
    $$$ThrowOnError(f.LineTerminatorSet($C(13,10)))
    
    // Write lines from SQL 
    &sql(DECLARE cur CURSOR FOR SELECT a, b into :a, :b	FROM table)
    &sql(OPEN cur)
    &sql(FETCH cur)
    do f.Write("a col, b col"_$C(13,10))
    while (SQLCODE = 0) {
        s line = ""_a_","_b_""
        do f.Write(line) // NOTE: workaround here of do f.Write($zconvert(line,"O","UTF8"))
        do f.Write($C(13,10))
        &sql(FETCH cur)
    }
    &sql(CLOSE cur)
    
    // Clean up
    do f.Close()
    $$$ThrowOnError(f.%Save())
    return 1
} catch err {
    do err.Log()
    write "Error exporting file."
}

The SQL table has two columns a and b, whose values can contain special characters. For the example, say the characters are エッジ

I ran into an issue here that special characters were not properly handled in the exported file. I expected to be able to set a standard character encoding of UTF-8 on the file itself, but after a deep dive into %Library.File in the documents, and all the classes it inherits from, I was unable to find anything regarding character encoding or any conversation on this.

I ended up using a $zconvert with "O" mode to "UTF8" on each line to ensure on a line by line basis the proper encoding was used as

do f.Write($zconvert(line,"O","UTF8"))

This works perfectly well. But, I remain curious if anyone is aware of character encoding, historically or currently, for a File type. And/or knows or has opinions on why this is not a property of the File. Just wanted to open this up for discussion.

Thanks anyone for your thoughts!