setup.mcache: Cacheing objects for lazy-load access

In mvbutils: Workspace Organization, Code and Documentation Editing, Package Prep and Editing, Etc

Description

Manually setup existing reference objects– rarely used explicitly.

Usage

setup.mcache( envir, fpath, refs)

Arguments

envir	environment or position on the search path.
fpath	directory where "obj*.rda" files live.
refs	which objects to handle– all names in the mcache attribute of envir, by default

Details

Creates an active binding in envir for each element in refs. The active binding for an object myobj will be a function which keeps the real data in its own environment, reading and writing it as required. Writing a new value will give attr( envir, "mcache")[ "myobj"] a negative sign. This signals that the "obj*.rda" file needs updating, and the next Save (or move or cd) command will do so. [The "*" is the absolute value of attr( envir, "mcache")[ "myobj"].] One wrinkle is that the "real data" is initially a promise created by delayedAssign, which will fetch the data from disk the first time it is needed.

Author(s)

Mark Bravington

See Also

mlazy, makeActiveBinding, delayedAssign

mvbutils documentation built on May 2, 2019, 8:32 a.m.