ThingLab

ThingLab is a visual programming environment implemented in Smalltalk¹ and designed at Xerox PARC by Alan Borning.

A conventional system allows a user to provide inputs that produce outputs. A constraint-oriented system, such as ThingLab, allows the user to provide arbitrary inputs or outputs, then solves for whatever is unknown. ThingLab is viewed as one of the earliest constraint-oriented systems.

ThingLab is credited in "Fumbling the Future" as a big reason Xerox continued to fund computer development.

References

Borning, Alan (October 1981). "The Programming Language Aspects of ThingLab, a Constraint-Oriented Simulation Laboratory". ACM Transactions on Programming Languages and Systems. 3 (4): 353–387. doi:10.1145/357146.35714 (inactive 22 April 2026). Retrieved March 11, 2026.{{cite journal}}: CS1 maint: DOI inactive as of April 2026 (link)

External links

Borning, A. (1979). ThingLab A Constraint-oriented Simulation Laboratory. Stanford University. Retrieved March 11, 2026.
ThingLab Sources

[1] Borning, Alan (October 1981). "The Programming Language Aspects of ThingLab, a Constraint-Oriented Simulation Laboratory". ACM Transactions on Programming Languages and Systems. 3 (4): 353–387. doi:10.1145/357146.35714 (inactive 22 April 2026). Retrieved March 11, 2026.{{cite journal}}: CS1 maint: DOI inactive as of April 2026 (link)

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