Sather

"For people with the surname, see Sather (surname)."
Sather is an object-oriented programming language. It originated circa 1990 at the International Computer Science Institute (ICSI) at the University of California, Berkeley, developed by an international team led by Steve Omohundro. It supports garbage collection and generics by subtypes.
Originally, it was based on Eiffel, but it has diverged, and now includes several functional programming features.
The name is inspired by Eiffel; the Sather Tower is a recognizable landmark at Berkeley, named after Jane Krom Sather, the widow of Peder Sather, who donated large sums to the foundation of the university.
Sather also takes inspiration from other programming languages and paradigms: iterators, design by contract, abstract classes, multiple inheritance, anonymous functions, operator overloading, contravariant type system.
The original Berkeley implementation (last stable version 1.1 was released in 1995, no longer maintained) has been adopted by the Free Software Foundation therefore becoming GNU Sather. Last stable GNU version (1.2.3) was released in July 2007 and the software is currently not maintained. There were several other variants: Sather-K from the University of Karlsruhe; Sather-W from the University of Waikato (implementation of Sather version 1.3); Peter Naulls' port of ICSI Sather 1.1 to RISC OS; and pSather, a parallel version of ICSI Sather addressing non-uniform memory access multiprocessor architectures but presenting a shared memory model to the programmer.
The former ICSI Sather compiler (now GNU Sather) is implemented as a compiler to C, i.e., the compiler does not output object or machine code, but takes Sather source code and generates C source code as an intermediate language. Optimizing is left to the C compiler.
The GNU Sather compiler, written in Sather itself, is dual licensed under the GNU GPL & LGPL.
Hello World.
 class HELLO_WORLD is
 main is 
 #OUT+"Hello World\n"; 
 end; 
 end;
A few remarks:
Example of iterators.
 class MAIN is
 main is
 loop
 i := 1.upto!(10);
 #OUT + i + "\n";
 end;
 end;
 end;
This program prints numbers from 1 to 10.
The codice_10 ... codice_11 construct is the preferred means of defining loops (although codice_12 and codice_13-codice_14 are also available). Within the construct, one or more iterators may be used. Iterator names always end with an exclamation mark (this convention is enforced by the compiler). codice_15 is a method of the integer class codice_16 accepting one codice_17 argument, meaning its value will not change as the iterator yields. codice_15 could be implemented in the codice_16 class like this:
 upto!(once m:INT):SAME is
 i: INT := self; -- initialise i to the value of self, 
 -- that is the integer of which this method is called
 loop
 if i>m then 
 quit; -- leave the loop when i goes beyond m
 end;
 yield i; -- else use i as return value and stay in the loop
 i := i + 1; -- and increment
 end;
 end;
Type information for variables is denoted by a postfix syntax codice_20. The type can often be inferred and thus the typing information is optional, like in codice_21. codice_22 is a convenience pseudo-class referring to the current class.