A read-only view over a base daf.

A ViewDaf carries a reference to a base DafReader and a dictionary of per-name query overrides (axes / scalars / vectors / matrices). Reads on the view rewrite into queries against the base; no data is copied.

Usage

ViewDaf(
  name = character(0),
  internal = new.env(parent = emptyenv()),
  cache = new.env(parent = emptyenv()),
  axis_version_counter = new.env(parent = emptyenv()),
  vector_version_counter = new.env(parent = emptyenv()),
  matrix_version_counter = new.env(parent = emptyenv()),
  base = DafReader(),
  view_axes = list(),
  view_axis_renames = list(),
  view_axis_indices = list(),
  view_scalars = list(),
  view_vectors = list(),
  view_matrices = list()
)

Arguments

name

Character scalar; name of the view.

internal

Internal environment (created by new_internal_env()).

cache

Cache environment (created by new_cache_env()).

axis_version_counter

Counter environment for axis version tracking.

vector_version_counter

Counter environment for vector version tracking.

matrix_version_counter

Counter environment for matrix version tracking.

base

Base DafReader this view wraps.

view_axes

Named list mapping view axis names to query strings.

view_axis_renames

Named list mapping view axis names to base axis names.

view_axis_indices

Named list mapping view axis names to 1-based integer vectors of positions within each base axis that the view exposes.

view_scalars

Named list mapping view scalar names to query strings.

view_vectors

Named list mapping "axis|name" keys to override specs.

view_matrices

Named list mapping "rows|cols|name" keys to override specs.

Details

Users should construct ViewDaf objects via viewer() rather than calling the constructor directly.

See also

viewer()

Examples

d <- example_cells_daf()
v <- viewer(d)
inherits(v, "dafr::ViewDaf")
#> [1] TRUE