Copyright (c) 2007-2017 MIT 6.005/6.031 course staff, all rights reserved. Redistribution of original or derived work requires permission of course staff.
This is a mailing list application for processing and analyzing email list expressions. It supports email list expressions inputted from the console as well as from the web.
List expressions are sets of recipients who should receive email messages. A list expression may be an expression, a sequence of list expressions, a list name (set of recipients of a mailing list), an email address (single recipient), or an empty string.
Expressions use the following operators:
- , (union)
- ! (difference)
- * (intersection)
- = (definition)
- ; (sequencing)
The order of operations in descending order is: '*', '!', ',', '=', and ';'. The user may also nest subexpressions in parentheses.
A list expression may define a list name: listname = e defines listname as the expression e and returns the set of recipients of e. List names are nonempty case-insensitive strings of letters, digits, underscores, dashes, and periods.
Sequencing of list expressions or list definitions:
- Ex:
x = a@mit.edu,b@mit.edu ; x * b@mit.edu. After substituting for x in the second part of the expression, this expression is equivalent to(a@mit.edu,b@mit.edu) * b@mit.edu, which represents the single recipient b@mit.edu.
The output of this console is an order-independent view of the emails specified in an email list expression.
Lastly, the user can use the commands !save or !load to save currently defined named lists to a file or load a saved file. Saved files contain a single valid list expression (a sequence of list definitions). A user can specify multiple files in the same !load command but must separate the files by a comma.
If a filename does not contain a valid list expression (during loading), or the file is unreadable (during saving), then a readable error is returned.
If given no input, this console proceeds to wait until valid input is given.