Agena 1.0.1

Major Features:

1. Agena offers various flow control facilities such as
   • if/then/elif/else conditions,
   • case of/else conditions similar to C's switch/case statements,
   • is operator to return alternative values,
   • numerical for/from/to/by loops where start, stop, and step values are optional, and automatic round-off error correction of iteration variables,
   • combined numerical for/while loops,
   • for/in loops over strings and complex data structures,
   • while and do/as loops similar to Modula's while and repeat/until not() iterators,
   • a skip statement to prematurely trigger the next iteration of a loop,
   • a break statement to prematurely leave a loop,
   • data type validation with the try/else statement and the optional double colon facility in parameter lists.
2. Data types provided are:
   • rational and complex numbers, with extensions such as infinity and undefined,
   • strings,
   • Booleans such as true, false, and fail,
   • the null value meaning 'nothing',
   • multi-purpose tables implemented as associative arrays to hold any kind of data, taken from Lua,
   • Cantor sets as collections of unique items,
   • sequences, i.e. vectors, to internally store items in strict sequential order,
   • pairs to hold two values or pass arguments in any order to procedures,
   • user-defined types for sequences, tables, and pairs to allow for special-purpose handling,
   • threads, userdata, and lightuserdata inherited from Lua.
3. Procedures with full lexical scoping are supported, as well, and provide the following extensions:
   • the << (args) -> expression >> syntax to easily define simple functions,
   • remember tables to conduct recursion at high speed and at low memory consumption,
   • remember tables for fast access to predefined results,
   • user-defined types,
   • the nargs system variable which holds the number of arguments actually passed to a procedure,
   • metamethods inherited from Lua to define operations for tables, sets, sequences, and pairs.
4. Some other features are:
   • graphical capabilities for the Solaris, Mac OS X, Linux, and Windows versions,
   • an arbitrary precision mathematical library,
   • easy configuration of your personal environment via the Agena initialisation file,
   • an easy-to-use package system also providing a means to load a library and define short names for all package procedures at a stroke (with function),
   • enumeration and multiple assignments,
   • scope control via the scope/epocs keywords,
   • the external switch to a numeric for loop to pass the last iteration value to its surrounding block,
   • functions to support fast text processing (see in, replace, lower, and upper operators, as well as the functions in the strings and utils packages),
   • the binio package to easily write and read files in binary mode,
   • facility to store any Agena data to a file and read it back later into a new session (save and read functions),
   • efficient statements for stack programming (insert/into and pop/from),
   • undergraduate Calculus, Linear Algebra, and Statistics packages,
   • bitwise operators,
   • direct access to the file system,
   • xBase file support (compliant to dBASE III) to exchange data with standard applications.

Enhancements:

• With structures, the `inc` and `dec` statements only worked correctly with one-dimensional tables or sequences. This has been changed.
• The `has` function returned unwanted results with tables if its second argument is a number and if this number is a key of the table scanned. This has been changed: Only if the key is not of type number, then the table indices are scanned, as well.
• Corrected error message of `arccosh`.
• The prettyprinter now outputs complex values including `undefined` in the real or imaginary part as just `undefined`. Note that internally, the complex value is not simplified this way but left untouched.