R/utils.R

In AliciaSchep/vlbuildr: Build Vega-Lite Specs in R

TOP_LEVEL_KEYS <- c(
  "$schema", "autosize", "background", "config", "datasets",
  "padding", "usermeta"
)


.make_object <- function(inputs, override, exclude) {
  # Remove nulls
  inputs <- inputs[!vapply(inputs, is.null, FALSE)]
  
  if (".object" %in% names(inputs)) {
    obj <- inputs[[".object"]]
    if (any(!(names(inputs) %in% c(exclude,"spec",".object")))) {
      warning("Ignoring some inputs as .object was passed in.")
    }
  } else {
    obj <- inputs[!(names(inputs) %in% c(exclude, "spec", "..."))]    
  }

  if (!is.null(override)) {
    obj <- utils::modifyList(obj, override)
  }
  
  obj
}


.add_to_top_spec <- function(spec, x, name, ref,
                             how = c("replace", "append", "match")) {
  how <- match.arg(how)

  res <- validate_sub_schema(x, ref)

  if (how == "replace") {
    spec[[name]] <- x
  } else if (how == "append") {
    if (!hasName(spec, name)) {
      spec[[name]] <- list()
    }
    spec[[name]] <- c(spec[[name]], list(x))
  } else {
    spec[[name]] <- modifyList(spec[[name]], x)
  }

  spec
}

.add_to_inner_spec <- function(spec, x, name, ref,
                               how = c("replace", "append", "match")) {
  how <- match.arg(how)

  fn <- function(spec) {
    .add_to_top_spec(spec, x, name, ref, how)
  }

  modify_inner_spec(spec, fn)
}



modify_inner_spec <- function(spec, ...) {
  UseMethod("modify_inner_spec", spec)
}

modify_inner_spec.vegaspec_concat <- function(spec, fn) {
  stop("Can't apply change to a concat spec; apply prior to concatenating")
}

modify_inner_spec.vegaspec_hconcat <- function(spec, fn) {
  stop("Can't apply change to a hconcat spec; apply prior to concatenating")
}

modify_inner_spec.vegaspec_vconcat <- function(spec, fn) {
  stop("Can't apply change to a vconcat spec; apply prior to concatenating")
}

modify_inner_spec.vegaspec_layer <- function(spec, fn) {
  # Layer spec can have most 'inner' spec properties...
  # Exceptions: mark & selection
  # Functions calling this helper should have a separate
  # layer spec function if needed...
  fn(spec)
}


modify_inner_spec.vegaspec_repeat <- function(spec, fn) {
  spec$spec <- fn(spec$spec)
  spec
}

modify_inner_spec.vegaspec_facet <- function(spec, fn) {
  spec$spec <- fn(spec$spec)
  spec
}

modify_inner_spec.vegaspec_unit <- function(spec, fn) {
  fn(spec)
}


.extract_inner_spec <- function(spec) {
  keep <- intersect(TOP_LEVEL_KEYS, names(spec))
  move <- names(spec)[which(!(names(spec) %in% keep))]
  list(outer = spec[keep], inner = spec[move])
}

.extract_inner_specs <- function(...) {
  modified <- lapply(list(...), .extract_inner_spec)
  inners <- lapply(modified, function(x) x[["inner"]])
  outers <- lapply(modified, function(x) x[["outer"]])
  list(inners = inners, outers = outers)
}

.get_inline_data <- function(spec) {
  if (!hasName(spec, "data") || !hasName(spec$data, "values")) {
    NULL
  } else {
    spec$data$value
  }
}