Editing UNCOL

'''UNCOL''' ('''Universal Computer Oriented Language''') is a universal [[intermediate language]] for [[compiler]]s. The idea was introduced in 1958, by a [[SHARE (computing)|SHARE]] ad-hoc committee.<ref>{{cite journal |last1=Strong |first1=J. |last2=Wegstein |first2=J. |last3=Tritter |first3=A. |last4=Olsztyn |first4=J. |last5=Mock |first5=O. |last6=Steel |first6=T. |title=The Problem of Programming Communication with Changing Machines: A Proposed Solution |journal=Communications of the ACM |date=August 1958 |volume=1 |issue=8 |pages=12–18 |doi=10.1145/368892.368915 |doi-access=free }}</ref> It was never fully specified or implemented; in many ways it was more a concept than a language.

UNCOL was intended to make compilers economically available for each new [[instruction set]] [[computer architecture|architecture]] and [[programming language]], thereby reducing an N×M problem to N+M.<ref>{{cite mailing list |url=https://mailarchive.ietf.org/arch/msg/dmarc/mWIrFuomDC50hxgPi4QvO8VM6yQ |title=UNCOL and Reversing modifications from mailing lists |date=23 November 2021 |access-date=24 November 2021 |mailing-list=dmarc-ietf |author=[[John Levine]]}}</ref>  Each machine architecture would require just one compiler back end, and each programming language would require one compiler front end. This was a very ambitious goal because compiler technology was in its infancy, and little was standardized in computer hardware and software.

==History==
The concept of such a universal intermediate language is old: the 
[[SHARE (computing)|SHARE]] report (1958) already says "[it has] been discussed by many independent persons as long ago as 1954." Macrakis (1993) summarizes its fate:

{{quote|UNCOL was an ambitious effort for the early 1960s. An attempt to solve the compiler-writing problem, it ultimately failed because language and compiler technology were not yet mature.
In the 1970s, [[compiler-compiler]]s ultimately contributed to solving the problem that UNCOL set itself: the economical production of compilers for new languages and new machines.}}

UNCOL is sometimes used as a generic term for the idea of a universal intermediate language. The [[Architecture Neutral Distribution Format]] is an example of an UNCOL in this sense, as are various [[bytecode]] systems such as [[UCSD Pascal]]'s [[p-code machine|p-code]], and most notably [[Java bytecode]].<ref>John English, ''Introduction to Operating Systems: Behind the Desktop'', Palgrave MacMillan 2005, {{isbn|0230374085}}, p. 10</ref>

==See also==
*[[LLVM]]
*[[GIMPLE]]

==Notes==
<references/>

==References==

<!-- from Macrakis 1993 (inserted by Macrakis, 2006) -->
*{{cite journal|last1=Conway|first1=Melvin E.|title=Proposal for an UNCOL|journal=Communications of the ACM|date=1 October 1958|volume=1|issue=10|pages=5–8|doi=10.1145/368924.368928 |issn=0001-0782|doi-access=free}}
* Jean E. Sammet, ''Programming Languages: History and Fundamentals'', Prentice-Hall, 1969. Chapter X.2: UNCOL (Significant Unimplemented Concepts), p.&nbsp;708.
* [[SHARE (computing)|SHARE]] ''Ad-Hoc'' Committee on Universal Languages (J. Strong, J. Olsztyn, J. Wegstein, O. Mock, A. Tritter, T. Steel), "The Problem of Programming Communication with Changing Machines", ''Communications of the ACM'' '''1''':8:12–18 (August 1958) and '''1''':9:9–15 (September 1958).
* Stavros Macrakis, "From UNCOL to ANDF: Progress in Standard Intermediate Languages", White Paper, [[Open Software Foundation]] Research Institute, RI-ANDF-TP2-1, January, 1992. Available at [http://citeseer.ist.psu.edu/macrakis93from.html CiteSeer]
* T.B. Steel, Jr., "UNCOL: Universal Computer Oriented Language Revisited", ''Datamation'' (Jan/Feb 1960), p.&nbsp;18.
* T.B. Steel, Jr., "A First Version of UNCOL", ''Proc. Western Joint Computer Conference'' '''19''':371 (Los Angeles, May 9–11, 1961).
* T.B. Steel, Jr., "UNCOL: The Myth and the Fact", ''Annual Review in Automatic Programming'' '''2''':325 (1961).

[[Category:Compilers]]