A pattern up to 512 characters compiles; a longer one is refused naming the limit

mvzr's Regex holds 64 operations, so a pattern much past 64 bytes was refused as bad regular expression. pardes now compiles into mvzr's SizedRegex(512, 64), and a pattern that is too long (told apart from a malformed one by compiling it with room) says it is longer than mvzr's 512 operations.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

1 files changed, 4 insertions, 1 deletions

diff --git a/docs/fs.md b/docs/fs.md
index 7b1e47bf..9ca5f936 100644
--- a/docs/fs.md
+++ b/docs/fs.md
@@ -713,7 +713,10 @@ whole text: never a search that silently finds nothing. An alternation
 whose every branch starts with `^` (`^def|^ `) finds a line that starts
 either way (it is taken as `^(def| )`); one that mixes anchored and
 unanchored branches (`^def|x`) is refused, `bad regular expression`, since
-mvzr keeps `^` only first. An expression is
+mvzr keeps `^` only first. A pattern may be up to 512 of mvzr's operations,
+about 512 characters (mvzr's own is 64; pardes builds it with more); a
+longer one is refused, `bad regular expression: longer than mvzr's 512
+operations`. An expression is
 evaluated from the current address, the range last written to `addr` (or
 left by the last `data` write, just past it), as acme evaluates it from
 `w->addr` (xfid.c:446): `.` is that address, not the selection (`dot` is