Re: Using a hash-table context property

[David Kastrup]

Dan Eble <address@hidden> writes:

> After adding a property to define-context-properties.scm and
> initializing it in Score context in engraver-init.ly
> <http://engraver-init.ly/> to a hash table created with
> alist->hash-table, my engraver is able to get the table and use it.
> My problem is that the entries the engraver adds persist to the next
> score!  I was expecting the next score to start again with the default
> table given in engraver-init.ly <http://engraver-init.ly/>.  What am I
> missing?

Well, your included links seem a bit optimistic.  I doubt you reserved
the engraver-init.ly domain just for this request.

At any rate, ly/declarations-init.ly contains

#(define default-fret-table (make-hash-table 101))
#(define chord-shape-table (make-hash-table 29))
#(call-after-session
  (lambda ()
   (hash-clear! default-fret-table)
   (hash-clear! chord-shape-table)))

and there is a reason for that.  It would not help restoring the hash
table to the original hash table at the end of a session since hash
tables are modified in-place and thus the hash table _is_ the original
hash table, just in modified state.

-- 
David Kastrup