R/spq_set.R

In lvaudor/glitter: glitter makes SPARQL

#' Set helper values for the query
#'
#' @description Set helper values for the query (helps with readability)
#' @param .query query
#' @param ... Helper values and their definition.
#'
#' @return A query object
#' @export
#'
#' @section Some examples:
#'
#' ```r
#' # find the individuals of the species
#' spq_init() %>%
#' # dog, cat or chicken
#' spq_set(species = c('wd:Q144','wd:Q146', 'wd:Q780'), mayorcode = "wd:Q30185") %>%
#' spq_filter(mayor == wdt::P31(species)) %>%
#' spq_add("?mayor p:P39 ?node") %>%
#' # of mayor
#' spq_add("?node ps:P39 ?mayorcode") %>%
#' # of some places
#' spq_add("?node pq:P642 ?place") %>%
#' spq_label(species, mayor, place) %>%
#' spq_select(-species, -place, -node, -mayor, -mayorcode) %>%
#' spq_perform()
#' ```
spq_set = function(.query, ...) {
  args = rlang::enquos(...)

  subjects = names(args)
  values = purrr::map_chr(args, treat_value)

  .query <- purrr::reduce2(
    subjects,
    values,
    add_one_value_var,
    .init = .query
  )

  # TODO: -select by default?
  return(.query)
}

treat_value = function(value) {
  sprintf("{%s}", paste0(rlang::eval_tidy(value), collapse = " "))
}

add_one_value_var <- function(query, var, values) {
  track_vars(
    query,
    name = var,
    values = values
  )
}