From: "Randy Brukardt" <randy@rrsoftware.com>
Subject: Re: recursive map specification
Date: Wed, 26 Jun 2019 00:23:45 -0500
Date: 2019-06-26T00:23:45-05:00 [thread overview]
Message-ID: <qeuvh1$fiv$1@franka.jacob-sparre.dk> (raw)
In-Reply-To: 187147dc-94fe-4019-bc42-5b214db452db@googlegroups.com
<mario.blunk.gplus@gmail.com> wrote in message
news:187147dc-94fe-4019-bc42-5b214db452db@googlegroups.com...
> Hello,
>
> I want to specify a recursive map. To simplify the problem I use the
> example of a person and its ancestors and ancestors ... The problem does
> not seem special but I haven't found a solution. The approach below does
> not compile:
>
> type person is record
> name : unbounded_string;
> end record;
>
> package tree is new ordered_maps
> (
> key_type => person,
> element_type => tree.map -- compiler error. "tree" undefined
> );
>
> Any ideas ? Thanks a lot !
This is the reason that we defined the Multiway_Tree, as it isn't sensible
to define a recursive container. (Otherwise, a recursive list is essentially
a tree.) If you also need a map (for instance, to make the names easily
found), I'd suggest making a map of tree cursors, and keep the real data in
the tree (where the relationships also live).
Randy.
prev parent reply other threads:[~2019-06-26 5:23 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-25 8:21 recursive map specification mario.blunk.gplus
2019-06-25 8:44 ` Egil H H
2019-06-25 9:09 ` mario.blunk.gplus
2019-06-25 9:22 ` Egil H H
2019-06-25 9:24 ` mario.blunk.gplus
2019-06-26 5:23 ` Randy Brukardt [this message]
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