The entire process of packaging EO objects and atoms into JAR artifacts is explained in this blog post: Objectionary: Dictionary and Factory for EO Objects. It’s pretty straightforward. However, there is one tricky situation related to placing compiled Java binaries into the JAR. This process may go wrong and sometimes it does. In version 0.24.0 of our Maven plugin we introduced a pair of options for the unplace goal. Here is how they work.

Since version 0.23.16 it is possible to use switch object just like this:

memory "swordfish" > password

QQ.switch
  *
    password.eq "swordfish"
    "password is correct!"
  *
    password.eq ""
    "empty password is not allowed"
  *
    FALSE
    "password is wrong"

Here, switch object returns “password is correct!”, which is the first true case in this statement. The switch object consists of arrays with arrays of two elements: condition and return value.

If the above parameters are missing, switch will return an error object with msg as a string message.

When you compile your EO code, the compiler discovers which objects are “foreign” and tries to find them in Objectionary. It finds them, downloads, and then compiles locally. The problem is that the objects in Objectionary are not static: they get new versions very often. That’s why, in order to stabilize your build, you may want to use their fixed versions.

Since version 0.23.15 it is possible to use number object just like this:

# this is 7
(QQ.math.number -7).abs

It is a decorator of int and float objects with the following additional attributes:

There is eoc, a command line tool that helps you automate compilation, transpilation, and execution of simple EO programs. With this tool you can also create and execute unit tests. Just name them *-test.eo and add metas +junit to them.

Since version 0.23.8 it is possible to use string.slice object just like this:

"Привет".slice 1 2

Here, the slice object returns the “ри” string, which is a substring of the “Привет” string from the specified start position and with the length len.

If the above parameters are out of bounds, slice will return an error object instead of a new string object.

Until version 0.23.7 it was possible to use memory object just like this:

memory > m
m.write 42

On the first line, a copy of memory was made and then labeled as m. This was a bug in the language. The object memory must not be copied if there are no arguments provided for the copying (application) operation.

Since version 0.23.6 of EO we got rid of the char object. We want to simplify the core of the language and believe that this object can be easily replaced with its actual representation, i.e. an array of bytes. Now, if you want to get a character, you can just use the string object instead. All of these examples are valid strings: "\u0123", "h", "\t", "\n" and "\07". We got rid of the string.char-at and bytes.as-char objects.