Hank Bromley

From Lisp Machine to language lab

A general method is described for using a Lisp Machine to study reading as it takes place. The method involves simulating, on the machine’s CRT, a moving window that passes through the text being read. The speed and direction of the window can be controlled by the reader, or test probes can be coordinated within the text viewed. The method allows reading to occur in an easily monitored environment, and the reader can respond to the material being read in a flexible manner. Suggestions for programming the Lisp Machine are provided which lead to improved overall execution speed and constancy of runtime for specific pieces of code in on-line experiments.

Signaling and Handling Conditions

The material for this chapter comes entirely from Part XI of volume 2 of the Symbolics documentation.

The Card Game Example

This program grew out of a discussion I had with Muffy Barkocy after seeing her Solitaire program for earlier releases. The basic idea of this program is to provide a solitaire-program substrate. The idea was to enable programmer to implement a new solitaire game in an hour or so.

The Calculator Example

This chapter is very much like the graph example two chapters back — a later section contains a code listing, and this one describes some of the new features1 of the system used in the code. This program is derived from a program originally written by Dan Weinreb, and rewritten for Genera 7.0 by Mike McMahon.

Systems, Storage and Errors

This chapter is for people who want to write applications programs and package them professionally. I will be discussing topics which programmers need to understand eventually if they want to write completely self-contained software that is easy to install and run and doesn’t scare its users.

More Advanced Use of the Editor

The standard Zwei and Zmacs1 commands are generally quite well documented by the on-line help facilities, both within the Document Examiner and within Zmacs itself. Thus, there should be no difficulty in becoming fluent in the use of the built-in commands simply by consulting the automatic documentation. Or, if you prefer, many of the more common built-in commands are described on paper: See the section “Writing and Editing Code” in Program Development Utilities.

Flow of Control

In this chapter we leave behind the “operating system” of the lisp machine and return to aspects of the lisp language itself. In particular, we’ll look at the various constructs for determining the flow of control. The notes are a little sketchier than usual, because this material is covered reasonably well in Part V of volume 2 of the Symbolics documentation.

A Quick Look at “The Network”

Although it is common to refer to a lisp machine’s connections to the rest of the world as “the network,” as if the machine were connected via a single mechanism to a unified system of linkages, such is not the case. There are several means of communication, operating via several different hardware and software protocols. And there is considerable overlap, with different software protocols operating simultaneously over the same hardware. It’s not really very complicated, but it’s easy to become highly confused if the basic issues are not kept clear.

The Graph Example

This chapter, rather than present some abstracted features of the lisp language or of the lisp machine operating environment, will cover a programming example which puts to use many of the features we have previously discussed. The piece of code in question allows one to display and manipulate simple undirected graphs, that is sets of nodes connected by arcs.

The Tree Example

This chapter is very much like the graph example two chapters back — a later section contains a code listing, and this one describes some of the new features* of the code. Much of the code was copied directly from the graph example (with “graph” changed to “tree”). The most interesting of the new parts have to do with menus.