Introduction

The last assignment added to readmbox a new version of the order command. This assignment adds to readmbox a new version of the delete command.

The delete command deletes messages from the message list. Currently, the delete command has two forms:

delete label word

to delete messages containing word in header fields, and

delete

to restore the deleted messages, if any, to the message list. In this assignment you'll add a third format for the delete command.

The new delete command format is

delete word op word

where op indicates either and or or.

The sequence word₁ and word₂ corresponds to any message that has both word₁ and word₂ in its header. The two words do not have to appear in the same field, they just have to appear in the header. The command

delete word₁ and word₂

deletes all messages that have both word₁ and word₂ in their header. For example, the command

delete money and bulk

would delete the message

Subject: Make money fast.
Priority: bulk

blah blah blah

but not the message

Subject: Make body fast.
Priority: spam

Too skinny?  Add bulk in minutes with very little money blah blah blah

because the message header contains neither "money" nor "bulk"

The sequence word₁ or word₂ corresponds to any message that has either word₁ and word₂ in its header. The two words do not have to appear in the same field, they just have to appear in the header. The command

delete word₁ or word₂

deletes all messages that have either word₁ and word₂ in their header.

The delete command doesn't change when it has zero or two arguments; this assignment just adds a new behavior when the delete command has three arguments.

This page last modified on 1 August 2000.