[plt-scheme] continuing to write newbie notes on units; feedback?

From: Matthias Felleisen (matthias at ccs.neu.edu)
Date: Tue Jul 26 15:44:26 EDT 2005

On Jul 25, 2005, at 9:52 PM, Danny Yoo wrote:

>   For list-related administrative tasks:
>   http://list.cs.brown.edu/mailman/listinfo/plt-scheme
> Hi everyone,
> I'm still trying to write a tutorial on Units for people who've never 
> seen
> them before.  Here are the state of the notes now:
>     http://hkn.eecs.berkeley.edu/~dyoo/plt/unit-notes.text
> I finished writing a section on treating units as functors.  This has 
> to
> be obvious to everyone else, but for folks who haven't had much 
> experience
> with ML-style functors, this is exciting stuff.  *grin*

You may wish to read 
http://www.ccs.neu.edu/home/matthias/Tmp/SML/index.html These are notes 
from a lecture in an SE course from 1998. They are highly influenced by 
the work on units we had done. And you're absolutely right: units are 
connected to functors and the functorial style of programming that I 
experienced during my sabbatical at CMU in 1994.

> I'm about to start diving into the use of units in others parts of the 
> Scheme system, and would like some suggestions before I jump in too
> deeply.  I think the next part I'll need to cover is signed units, but
> we'll see... I want to jump into how units are applied in PLT Scheme as
> soon as I can.

A lot of uses of units have been replaced with modules. All first-order 
ones to be precise.

> Also, I did have a question about mixins; are they intrinsically tied 
> to
> units still?

They never were. The 1998 paper just shows how first-class modules and 
classes solve a particular SE problem easily.

-- Matthias

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