Getting Started

From Erights

This page contains some helpful tips for people who are planning on learning E.

Where to start

• You should have basic knowledge of Java and its class path system.
• Download and install E
• Read the Walnut - it is the most concise text on the E language and library.
• Bookmark the ELib api
• Either download the E source or open the e.jar (for example with unzip) and take a look around
• You can get informations about E objects by using the help() method. For example, open rune and enter

  ?help([])

  You will get information about the ConstList class and its methods.
• Take a look at the file org.erights.e.elang.syntax/syntax-props-default.txt. It contains information about various language constructs not explained elsewhere at this point. Here is the version of the file included in E version 0.8.37b.
• The source also contains a number of emakers that can be used when developing programs. For example:
  • org.erights.e.facet.makeStoneCast.emaker: An implementation of the Facets pattern
  • org.erights.e.facet.makeCaretaker.emaker: An implementation of the Revocable Capabilities pattern
  • org.erights.e.elib.slot.makeLamportSlot.emaker: An implementation of the EverReporter pattern/interface

Documentation and help

• The Walnut
• The ELib api
• Documentation on the ERights homepage. See List_of_papers
• The E mailing list. You can search the archives using google by including "site:eros-os.org" in the search field.

Other things you should know

Should be in Walnut?!?

• Declaring a Java class as safe for importing: Create a file with the extension .safej and save it to the same class path location as the java class you want to declare as safe. In the .safej file you can declare methods of that class as allowed or rejected. Take a look at the Safej_example. You can find more .safej files in the E distribution in the folder src/safej.