This is a special form: the argument must be a variable identifier. It returns a map where the keys are integers and the values are the date in physical times of the successive assignements to the variable. Integer 0 corresponds to the current value, 1 to the previous value, etc. Variable's history has a bounded length that can be specified using a @localor a@global declaration.

See also @tab_history, @map_history and @map_history_rdate.

See also System Related Functions @arch_darwin,    @arch_linux,    @arch_windows,    @compilation,    @configuration_arch,    @configuration_audiosample,    @configuration_debug,    @configuration_faust,    @configuration_host,    @configuration_release,    @configuration_target_architecture,    @current_load_directory,    @directory_read,    @exe_child_of,    @exe_parent,    @history_length,    @host_date,    @info,    @is_fastforward,    @is_following_on,    @is_paused,    @is_playing_on,    @is_running,    @is_stopped,    @max_absolute_path,    @max_patch_path,    @pwd,    @strip_path,    @system,    @Tracing,    @time,    @typecheck,    @UnTracing    @usage_resident_memory_size,    @usage_statistics,    @usage_virtual_memory_size    @user_directory