Get first name from string.R

# function to get first name from a string of names (including the particle e.g. von Frisch)
# strg = a string containing names
# NOTE: The function still needs further testing. Use with care!

get_author_name <- function(strg){
    # remove any leading and trailing whitespace
    strg <- trimws(strg)
    
    # check if string starts with two "nobiliary" particles
    logic_2prtcl <- grepl(pattern = "^van der|^von der", x = strg, perl=TRUE, ignore.case = TRUE)
    
    # if there are two particles then don't test for one particle anymore
    if (logic_2prtcl) {
        logic_1prtcl <- FALSE
    } else {
        # check if string starts with one "nobiliary" particle
        logic_1prtcl <- grepl(pattern = "^von|^van|^de|^der|^di|^d'|^lord", x = strg, perl=TRUE, ignore.case = TRUE)
    }
    
    # replace all punctuation with space (except apostrophe (caret symbol) and minus sign)
    strg <- gsub(pattern = "[^[:alnum:][:space:]'-]", replacement = ' ', strg, perl=TRUE)
    
    if (!any(logic_1prtcl, logic_2prtcl)) {
        # if there is no kind of particle, then take first element when splitting by space
        # also translate characters to upper
        # this is tested first because is the most common case and "if" will often stop here
        # without the need to waste time with further testing
        return(toupper(strsplit(strg, split=" ", fixed=TRUE)[[1]][1]))
    } else if (logic_1prtcl) {
        # if contains particle take first 2 elements when splitting by space
        # also translate characters to upper
        return(toupper(paste0(strsplit(strg, split=" ", fixed=TRUE)[[1]][1:2], collapse=" ")))
    } else {
        # if contains 2 particles take first 3 elements when splitting by space
        # also translate characters to upper
        return(toupper(paste0(strsplit(strg, split=" ", fixed=TRUE)[[1]][1:3], collapse=" "))) 
    }
}

# ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# EXAMPLES
get_author_name("Anders-Frisch, GJ; Johnson,")
[1] "ANDERS-FRISCH"
get_author_name("von Frisch, GJ; Johnson,")
[1] "VON FRISCH"
get_author_name("von Anders-Frisch, GJ; Johnson,")
[1] "VON ANDERS-FRISCH"
get_author_name("van der Anders-Frisch, GJ; Johnson,")
[1] "VAN DER ANDERS-FRISCH"
get_author_name("lord Anders-Frisch, GJ; Johnson,")
[1] "LORD ANDERS-FRISCH"
get_author_name("De Exemplu, GJ; Johnson,")
[1] "DE EXEMPLU"
get_author_name("An'der-son, GJ; Johnson,")
[1] "AN'DER-SON"
get_author_name("An' ders-on, GJ; Johnson,")
[1] "AN'"