The compiled-pattern cache

Every re_*() function compiles a character pattern through a cache of recently used compiled patterns, so a pattern used again, in a loop or across calls, is not recompiled. Patterns are keyed by their text, flags, dialect, literal and jit. The least recently used pattern is dropped when the cache is full. Patterns longer than 65,536 characters are never cached.

Usage

re_cache_size(n = NULL)

re_cache_clear()

Arguments

n

NULL to query the capacity, or a whole number from 0 to 256 to set it. 0 turns the cache off. Shrinking the cache drops the least recently used patterns.

Value

re_cache_size() returns the capacity; when setting it, the previous capacity, invisibly. re_cache_clear() returns the number of patterns it dropped, invisibly.

Details

re objects from re_compile() stay valid when the cache drops their pattern or is cleared.

Examples

re_cache_size()
#> [1] 128
old <- re_cache_size(16)
re_cache_size(old)
re_cache_clear()