p_functions_title: Get function titles

[trinker]

I used this function at work. DOn't know if it makes the cut but documenting it here for now.

#' Package Functions
#' 
#' List the functions from a package.
#' 
#' @rdname p_functions
#' @param package Name of the package you want the list of functions for.
#' @param all logical.  If \code{TRUE} all of the functions from the package 
#' will be displayed regardless of whether they're exported or not.
#' @param character.only logical. If \code{TRUE} the input is a variable 
#' containing the package name.
#' @keywords function package
#' @export
#' @examples
#' p_functions_title()
#' p_funs_title()
#' p_functions_title(pacman)
p_functions_title <- 
function (package, character.only = FALSE){

    if (!character.only & is.name(substitute(package))) {
        package <- deparse(substitute(package))
    }
    if (identical(package, character(0))) {
        package <- "base"
    }

    m <- pacman::p_funs(package, character.only = TRUE)
    db <- tools::Rd_db(package)
    therd <- db[grep(paste(sprintf("%s.Rd", m), collapse="|"), names(db), value = TRUE)]
    titles <- sapply(sprintf("%s.Rd", m), function(x) therd[[x]][[1]][[1]])
    titles[grepl("^NULL$", titles)] <- NA
    out <-data.frame(
        'function' = m,
        'title' = unlist(titles, use.names = FALSE), 
        stringsAsFactors = FALSE, check.names = FALSE
    ) 
    class(out) <- c("wide_table", class(out))
    out

}

#' @rdname p_functions
#' @export
p_funs_title <- p_functions_title

[Dasonk]

It might be better if we just merge that into p_funs. Just like a title=TRUE kind of parameter.