A set of predicates and assertions for checking the files of variables, such as length, names and attributes. Most of the documentation is on the assertive page. End-users will usually want to use assertive directly.
To install the stable version, type:
install.packages("assertive.files")
To install the development version, you first need the devtools package.
install.packages("devtools")
Then you can install the assertive.files package using
library(devtools)
install_bitbucket("richierocks/assertive.files")
Functions for files:
is_dir
checks if a path corresponds to a directory.
is_empty_file
checks if a path corresponds to an empty
file.
is_existing_file
checks if a path corresponds to an
existing file.
is_readable_file
, is_writable_file
, and
is_executable_file
check a file’s permissions. (Though they
are based upon base::file.access
, which sometimes gives
unexpected results under Windows.)
is_library
checks if a path corresponds to a library
that R knows about.
Functions for connections:
is_connection
checks if a variable is a connection.
is_bzfile_connection
, is_fifo_connection
,
is_file_connection
, is_gzfile_connection
,
is_pipe_connection
, is_socket_connection
,
is_terminal_connection
, is_text_connection
,
is_unz_connection
, and is_url_connection
check
for these specific connection types.
is_stderr
, is_stdin
, and
is_stdout
check for these standard connections.
is_incomplete_connection
,
is_open_connection
, is_readable_connection
,
and is_writable_connection
check for these properties of
connections.
Predicates that return a vector have two corresponding assertions.
For example, is_dir
has assert_all_are_dirs
and assert_any_are_dirs
.
Predicates returning a single logical value have one corresponding
assertion. For example, is_stdin
has
assert_is_stdin
.