New implementation of the Icon language

Jcon is a new, full-featured, Java-based implementation of the Icon programming language. The compiler, written in Icon, generates an intermediate representation that is optimized and then used to produce classfiles of Java bytecode. A four-chunk control-flow model handles goal-directed evaluation and produces constructs not expressible as Java code. The runtime system, written in Java, finds object-oriented programming a great advantage in implementing a dynamically typed language, with method calls replacing many conditional tests. An all-encompassing descriptor class supports values, references, and suspended operations. The procedure call interface is simple and incurs overhead for generator support only when actually needed. Performance is somewhat disappointing, and some limitations are annoying, but in general Java provides a good implementation platform.