From: Jim Weirich <jim@...>
Date: 2005-04-06T13:38:50+09:00
Subject: Re: [ANN] Rant 0.3.2

On Tuesday 05 April 2005 07:44 pm, Lionel Thiry wrote:
> > Actually they are.  Ok, there are no checks to enforce the acyclic nature
> > of the dependency graph, but the arcs of the graph are certainly
> > directed.
>
> In Rake, the existence of the graph is implicit, hidden in the Task
> instances themselves, there isn't any explicit global DAG object.
>
> Just pointing a fact, no offense. :)

None taken.  You are correct.  There is no one object that represents a 
DAG[1].  But a DAG is merely a graph with a set of nodes and directed arcs 
between the node (and no cycles too).  The Task objects form the nodes of the 
DAG and the directed arcs are implemented by named lookup in the task map.

You seem to imply there would be advantages to a more explicit DAG 
implementation.  I would be interested in hearing what you think those 
advantages might be.

-- 
-- Jim Weirich    jim@weirichhouse.org     http://onestepback.org
-----------------------------------------------------------------
"Beware of bugs in the above code; I have only proved it correct, 
not tried it." -- Donald Knuth (in a memo to Peter van Emde Boas)

[1] And since graphs are polylithic structures, you generally wouldn't 
implement a DAG with a single object ... but I don't think that was your 
point.