The Cornell program synthesizer
Tim Teitelbaum, Thomas Reps · Communications of the ACM · 1981
Programs are not text; they are hierarchical compositions of computational structures and should be edited, executed, and debugged in an environment that consistently acknowledges and reinforces this viewpoint. The Cornell Program Synthesizer demands a structural perspective at all stages of program development. Its separate features are unified by a common foundation: a grammar for the programming language. Its full-screen derivation-tree editor and syntax-directed diagnostic interpreter combine to make the Synthesizer a powerful and responsive interactive programming tool.