Icon (programming language)

Icon is a high-level programming language developed by Ralph Griswold and colleagues at the University of Arizona, first released in 1977 as a successor to Griswold's earlier string-processing language SNOBOL4, designed around a distinctive goal-directed evaluation model in which expressions can produce a sequence of results and succeed or fail, driving control flow through failure rather than through explicit boolean tests alone. Icon combines this goal-directed evaluation with high-level data structures such as lists, sets and tables, and its generator-based string-scanning facilities made it especially well suited to text processing and pattern matching tasks.