> On Oct 11, 2017, at 11:10 AM, George Neuner <gneun...@comcast.net>
> wrote:
>
> My (maybe wrong) reading of the docs suggests that to match a hash
> table, the table must be defined inline in the match clause.
This isn’t really accurate. The hash-table match pattern matches a hash
table itself, but it sounds like you want to do something else, wanting
to use a separate, known dictionary as a lookup table for
pattern-matching.
To do this, you probably want the `app` match pattern:
[(app (lambda (e) (dict-ref mydict e #f)) (? values val))
....]
That pattern will bind `val` to the result if it exists in the
dictionary (and is non-#f). If you wanted this to be cleaner, you could
wrap that pattern into a separate match expander.
Alexis
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