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3.1 Introduction

Hemlock provides three different abstractions which are used in combination to solve the text-editing problem, while other editors tend to mash these ideas together into two or even one.

File

A file provides permanent storage of text. Hemlock has commands to read files into buffers and write buffers out into files.

Buffer

A buffer provides temporary storage of text and a capability to edit it. A buffer may or may not have a file associated with it; if it does, the text in the buffer need bear no particular relation to the text in the file. In addition, text in a buffer may be displayed in any number of windows, or may not be displayed at all.

Window

A window displays some portion of a buffer on the screen. There may be any number of windows on the screen, each of which may display any position in any buffer. It is thus possible, and often useful, to have several windows displaying different places in the same buffer.