Programming Languages - L

Sample Program

L0 - Tech U Munich. Low level language, typed and with ususal flow control, but only 3-address expressions. Higher levels L1 and L2 were planned. "Brief Survey of L0", H. Scheidig, in Machine Oriented Higher Level Languages, W. van der Poel ed, N-H 1974, pp.239-247.

L6 - Bell Telephone Laboratories Low-Level Linked List Language. Ken Knowlton, 1965. List processing language, typeless. "A Programmer's Description of L6, Bell Telephone Laboratories' Low-Level Linked List Language", K. Knowlton CACM 9(8):616-625 (Aug 1966). Sammet 1969, pp.400- 405.

Lace - Language for Assembling Classes in Eiffel. Specifies how to assemble an Eiffel system : in which directories to find the clusters, which class to use as the root, permits class renaming to avoid name clashes. "Eiffel: The Language", Bertrand Meyer, P-H 1992.

LADE - Compiler-compiler language?

LADY - "Key Concepts in the INCAS Multicomputer Project", J. Nehmer et al IEEE Trans Soft Eng SE-13(8):913-923 (Aug 1987).

Lakota - Scripting language, extends existing OS commands. info: Richard Harter <rh@smds.UUCP> SMDS Inc.

LAMBDA - A version of typed lambda calculus, used to describe semantic domains. "Outline of a Mathematical Theory of Computation", D.S. Scott, TM PRG-2, PRG, Oxford U, 1971.

lambda-Prolog - An extension of standard Prolog, in which terms are typed lambda-terms. Prolog/Mali compiler uses the MALI abstract memory system. info: list:

LAMINA - Concurrent object-oriented language. "Experiments with a Knowledge-based System on a Multiprocessor", Third Intl Conf Supercomputing Proc, 1988. "ELINT in LAMINA, Application of a Concurrent Object language", Delagi et al, KSL-88-3, Knowledge Sys Labs, Stanford U.

Language H - NCR. Early business-oriented language.

Laning and Zierler - J.H. Laning Jr and N. Zierler, 1953-1954. Possibly the first true working algebraic compiler. On MIT's Whirlwind computer. Sammet 1969, pp.131-132.

LAP - LISP Assembly Program. Assembly language embedded into early LISP. Sammet 1969, p.597. Also used by the Liar compiler for MIT Scheme, Emacs LISP, and MACLISP.

LAP4 - Early assembly language for Linc-8 machine.

LAPSE - Single assignment language for the Manchester dataflow machine. "A Single Assignment Language for Data Flow Computing", J.R.W. Glauert, M.Sc Diss, Victoria U Manchester, 1978.

Larch - John Guttag and Jim Horning <>. The Larch Project develops aids for formal specifications. Each Larch specification has two components: an interface containing predicates written in the LIL (Larch Interface Language) designed for the target language and a 'trait' containing assertions about the predicates written in LSL, the Larch Shared Language common to all. "The Larch Family of Specification Languages", J. Guttag et al, IEEE Trans Soft Eng 2(5):24-365 (Sep 1985). "Larch: Languages and Tools for Formal Specification", Guttag and Horning, Springer 1993.

Larch/Ada - Used in the Penelope verification system, to provide semantics for Ada' types. Notationally similar to Anna.

Larch/CLU - Larch specification language for CLU. Used in Abstraction and Specification in Program Development, B. Liskov & J. Guttag, MIT Press 1986.

LaTeX - see TeX.

LAU - Langage a Assignation Unique. Single assignment language for the LAU dataflow machine, Toulouse. "Pipelining, Parallelism and Asynchronism in the LAU System", J.C. Syre et al, Proc 1977 Intl Conf Parallel Proc, pp.87- 92.

LAURE - A language for knowledge representation combining object orientation and logic programming. Set operations. Object-oriented exception handling and a polymorphic type system. "An Object-Oriented Language for Advanced Applications", in Proc TOOLS 5, Santa Barbara 1991, P-H. info: Yves Caseau <>

LAVA - A language for VLSI that deals with "sticks", i.e. wires represented as lines with thickness. R.J. Matthews et al, "A Target Language for Silicon Compilers", IEEE COMPCON, 1982, pp.349-353.

LAX - LAnguage eXample. Toy language used to illustrate problems in compiler design. "Compiler Construction", W. M. Waite et al, Springer 1984.

LCC - Language for Conversational Computing. CMU 1960's. Similar to JOSS, with declarations, pointers and block structure from ALGOL-60. Implemented for IBM 360/370 under TSS. "LCC Reference Manual", H.R. Van Zoeren, CMU 1969.


1. The Larch interface language for ANSI standard C. J.V. Guttag et al, TR 74, DEC SRC, Palo Alto CA, 1991.

2. Liga Control Language. Controls the attribute evaluator generator LIGA, part of the Eli compiler-compiler. "LCL: Liga Control Language", U. Kastens <> , U Paderborn.

LCS - Language for Communicating Systems. Bernard Barthomieu. A concurrent SML with behaviors and processes, based upon higher order CCS. Implemented as a bytecode interpreter. Version 3.1 for Sun 3, Sun 4 info: Bernard Berthomieu <> list:

LDL - "LDL: A Logic-Based Data-Language", S. Tsur et al, Proc VLDB 1986, Kyoto Japan, Aug 1986, pp.33-41.

LDL1 - Successor of LDL. "Sets and Negation in a Logic Database Language", C. Beeri et al, in Proc 6th Ann ACM Symp Princs Database Sys (1987), pp.21- 37.

LDT - Logic Design Translator. Computer system design analysis. Sammet 1969, p.621.

LE/1 - Langage External. "An Evaluation of the LE/1 Network Command Language Designed for the SOC Network", J. du Masle, in Command Languages, C. Unger ed, N-H 1973.


1. LISP Extended Algebraic Facility. "An Algebraic Extension to LISP", P.H. Knowlton, Proc FJCC 35 (1969).

2. "LEAF: A Language which Integrates Logic, Equations and Functions", R. Barbuti et al in Logic Programming, Functions Relations and Equations, D. DeGroot et al eds, P-H 1986, pp.201-238.

Lean - U Nijmegen and U East Anglia. An experimental language based on graph rewriting, useful as an intermediate language. Descendant of Dactl0. "Towards an Intermediate Language Based on Graph Rewriting", H.P. Barendregt et al in PARLE: Parallel Architectures and Languages Europe, G. Goos ed, LNCS 259, Springer 1987, pp.159-175. (See Clean).

LEAP - Language for the Expression of Associative Procedures. ALGOL-based formalism for sets and associative retrieval, for TX-2. Became part of SAIL. "An ALGOL-based Associative Language", J.A. Feldman et al, CACM 12(8):439-449 (Aug 1969).

LECOM - Version of COMIT on GE 225 ca. 1966. Sammet 1969, p.419.

Leda - Tim Budd <>, Oregon State U, 1990-1993. Multiparadigm language (imperative, declarative, procedural, applicative, functional, logic, and object-oriented!) "Blending Imperative and Relational Programming", Tim Budd, IEEE Software 8(1):58-65 (Jan 1991). Forthcoming book.*

LeFun - MCC, Austin. Integration of logic and functional programming. "LeFun: Logic, Equations and Functions", H. Ait-Kaci et al, Proc 1987 Symp on Logic Programming, San Francisco.

Legion - Distributed language.

LEGOL - "Application of MP/3 to the Design and Implementation of LEGOL, A Legally Oriented Language", S.H. Mandil et al, Intl Symp Programming, Paris 1974.

Le-Lisp - Jerome Chailloux and Emmanuel St James, INRIA, France. A LISP dialect close to Common Lisp, lexically scoped, with a CLOS-like object system. Uses both packages and modules. "le-lisp: A Portable and Efficient Lisp System", J. Chailloux et al, Proc 1984 ACM Symp on Lisp and Functional Programming, ACM. Version v.16, available from ILOG, France.

Leo - General-purpose systems language, syntactically like Pascal and Y, semantically like C. "The Leo Programming Language", G. Townsend, CS TR 84-7, U Arizona 1984.

Lex -

1. Input language to the Lex scanner generator. "Lex - A Lexical Analyzer Generator", M.E. Lesk, CS TR 39, Bell Labs (Oct 1975). (See Flex). Implementation: ML-lex - Implementation and output in SML/NJ.

2. Lexical specification language for COPS. "Metalanguages of the Compiler Production System COPS", J. Borowiec, in GI Fachgesprach "Compiler-Compiler", ed W. Henhapl, Tech Hochs Darmstadt 1978, pp.122-159.

LG - Simple language for analytic geometry, with graphic output. "LG: A Language for Analytic Geometry", J. Reymond, CACM 12(8) (Aug 1969). [???]

LGDF - Large-Grain DataFlow. "A Large-grain Data Flow Scheduler for Parallel Processing on Cyberplus", R.G. Babb et al, Proc 1986 Intl Conf on Paralllel Proc, Aug 1986.

LGEN - Bell Labs. A logic language for VLSI implementation. S.C. Johnson, "Code Generation for Silicon", Proc 10th POPL, 1983.

LGN - Linear Graph Notation. A linearized representation of TCOL trees. B.W. Leverett et al, "An Overview of the Production Quality Compiler- Compiler Projects", TR CMU-CS-79-105, Carnegie Mellon 1979. (See TCOL)

Liana - 1991. Similar to C++, aimed at Windows applications. No pointers, no multiple inheritance. Garbage collection. "The Liana Programming Language", R. Valdes, Dr Dobbs J Oct 1993, pp.50-52. Base Tech, 1320 Peral St, Boulder CO.

LIDO - Input language for the attribute evaluator generator LIGA (a successor of GAG and a subsystem of the Eli compiler-compiler). LIDO is derived from GAG's input language ALADIN. "LIDO: A Specification Language for Attribute Grammars", U. Kastens <>, Fab Math-Inf, U Paderborn (Oct 1989).

LiE - Symbolic math aimed at Lie groups. "LiE, a Package for Lie Group Computations", M.A.A. van Leeuwen et al, in Computer Algebra Nederland, 1992 (ISBN 90-741160-02-7).

LIFE - Logic of Inheritance, Functions and Equations. Hassan Ait-Kacy <> et al, MCC, Austin, 1987. Object-oriented, functional, and constraint-based. Integration of ideas from LOGIN and LeFun. "Is There a Meaning to LIFE?", H. Ait-Kacy et al, Intl Conf on Logic Prog, 1991. - Wild_LIFE interpreter from Paradise project at DEC's Paris Research Lab list:

Lila - Patrick Salle'<>. A small assembly-like language used for implementation of Actor languages. [Plasma perhaps?]

LIMDEP - Linear programming language used by economists.

LIMP - "Messages in Typed Languages", J. Hunt et al, SIGPLAN Notices 14(1):27-45 (Jan 1979).

Linc - Burroughs/Unisys 4GL. Designed in New Zealand.

Lincoln Reckoner - ca 1965. Interactive math including matrix operations, on TX-2. "The Lincoln Reckonere: An Operation-Oriented On-line Facility with Distributed Control", A.N. Stowe et al, Proc FJCC 29 (1966). Sammet 1969, pp.245-247.

Linda - Yale. A "coordination language", providing a model for concurrency with communication via a shared tuple space. Usually implemented as a subroutine library for a specific base language. "Generative Communication in Linda", D. Gelernter <> ACM TOPLAS 7(1):80-112 (1985). "Linda in Context", N. Carreiro <> et al, CACM 32(4):444-458 (Apr 1989). (See C-Linda, Ease, Fortran-Linda, Glenda, LindaLISP, Lucinda, Melinda, Prolog-Linda).

LindaLISP - Yep, you guessed it.

Lingo - An animation scripting language. MacroMind Director V3.0 Interactivity Manual, MacroMind 1991.

LINGOL - LINguistics Oriented Language. Natural language processing. "A Linguistics Oriented Programming Language", V.R. Pratt, Third Intl Joint Conf on AI, 1973.

LIPL - Linear IPL. A linearized (i.e. horizontal format) version of IPL-V. Sammet 1969, p.394. R. Dupchak, "LIPL - Linear Information Processing Language", Rand Memo RM-4320-PR, Feb 1965.

LIS - Langage Implementation Systeme. Ichbiah, 1973. A predecessor of Ada, influenced by Pascal's data structures and Sue's control structures. A type declaration may have a low-level implementation specification. "The System Implementation Language LIS", J.D. Ichbiah et al, CII Honeywell-Bull, TR 4549 E/EN, Louveciennes France (Dec 1974). "The Two- Level Approach to Data Independent Programming in LIS", J.D. Ichbiah et al, in Machine Oriented Higher Level Languages, W. van der Poel ed, N-H 1974, pp.161-169.

LISA - Statistical data analysis. Similar to S.

LISP - LISt Processing. John McCarthy <> et al, MIT late 50's. Symbolic functional recursive language based on lambda- calculus, used especially for AI and symbolic math. Many dialects. Atoms and lists. Dynamic scope. Both programs and data are represented as list structures. Versions include LISP 1 (Original version), LISP 1.5 (MIT 1959), LISP 1.75, LISP 1.9.

LISP 2 - LISP 1.5 with an ALGOL60-like surface syntax. Also optional type declarations, new data types including integer-indexed arrays and character strings, partial-word extraction/insertion operators and macros. A pattern-matching facility similar to COMIT was proposed. Implemented for the Q-32 computer. "The LISP 2 Programming Language and System", P.W. Abrahams et al, Proc FJCC 29:661-676, AFIPS (Fall 1966).

LISP70 - LISP dialect, a descendant of MLISP and MLISP2. Also known as PLISP and VEL. Useful for parsing. Only the pattern-matching system was published and fully implemented. According to Alan Kay, LISP70 had an influence on Smalltalk-72. "The LISP70 Pattern Matching System, Larry Tesler et al, IJCAI 73.

LISP A - "LISP A: A LISP-like System for Incremental Computing", E.J. Sandewall, Proc SJCC 32 (1968).

Lispkit Lisp - Purely functional version of LISP. "Functional Programming, Application and Implementation", P. Henderson, P-H 1980.

Lisp-Linda - P. Dourish, U Edinburgh 1988.

LISP Machine LISP - An extension of Maclisp, now called Zetalisp.

Lisptalk - "Concurrent Programming Language Lisptalk", C. Li, SIGPLAN Notices 23(4):71-80 (Apr 1988).

LITHE - Object-oriented with extensible syntax. "LITHE: A Language Combining a Flexible Syntax and Classes", D. Sandberg, Conf Rec 9th Ann ACM Sym POPL, ACM 1982, pp.142-145.

LITTLE - Typeless language used to produce machine-independent software. LITTLE has been used to implement SETL. "Guide to the LITTLE Language", D. Shields, LITTLE Newsletter 33, Courant Inst (Aug 1977).

Little Smalltalk - A line-oriented near-subset of Smalltalk-80. "A Little Smalltalk", Timothy Budd, A-W 1987., source in C.

LLM3 - J. Chailloux. Assembly language for a virtual machine, the implementation language for Le-Lisp.

LM3 - The Larch interface language for Modula-3. (See Larch). "LM3: A Larch/Modula-3 Interface Language", Kevin D. Jones, TR 72, DEC SRC, Palo Alto CA.


1. Chalmers U Tech, Gothenburg, Sweden. Lazy, completely functional variant of ML[2]. Implemented on the G-machine, and used to implement the Haskell B compiler.*

2. Logical ML. Adds to Lazy ML a data type of 'theories' whose objects represent logic programs. "Logic Programming within a Functional Framework", A. Brogi et al, in Programming Language Implementation and Logic Programming, P. Deransart et al eds, LNCS 456, Springer 1990.

LNF - "A Fully Lazy Higher Order Purely Functional Programming Language With Reduction Semantics", K.L. Greene, CASE Center TR 8503, Syracuse U 1985.

L&O - Logic and Objects. Implemented as a front end for IC Prolog. "Logic and Objects", Frank McCabe, P-H. info: Zacharias Bobolakis <>

LO - Linear Objects. Concurrent logic programming language based on "linear logic", an extension of Horn logic with a new kind of OR- concurrency. "LO and Behold! Concurrent Structured Processes", J. Andreoli et al, SIGPLAN Notices 25(10):44-56 (OOPSLA/ECOOP '90) (Oct 1990).

{log} - "{log}: A Logic Programming Language with Finite Sets", A Dovier et al, Proc 8th Intl Conf Logic Prog, June 1991, pp.111-124.

LogC - C extension ncorporating rule-oriented programming, for AI applications. Production rules are encapsulated into functional components called rulesets. Uses a search network algorithm similar to RETE. "LogC: A Language and Environment for Embedded Rule Based Systems", F. Yulin et al, SIGPLAN Notices 27(11):27-32 (Nov 1992). Version: LogC 1.6.

Logic Design Language - Language for computer design. "A System Description Language Using Parametric Text Generation", R.H. Williams, TR 02.487, IBM San Jose, Aug 1970.

LOGIN - Integration of logic programming and inheritance. "LOGIN: A Logic Programming Language with Built-In Inheritance", H. Ait-Kaci et al, J Logic Programming 3(3):185-215 (1986).

LOGLAN - Inst Informatics, Warsaw U. Object-oriented. Not to be confused with Charles Brown's 'Loglan', a high-precision artificial language designed for humans, intended to test the Sapir-Whorf Hypothesis and investigate the mechanisms of natural learning. "LOGLAN '88 - Report on the Programming Language", LNCS 414, Springer, ISBN 3-540-52325-1.

LOGLISP - Robertson & Sibert, Syracuse 1980. A Prolog-like language called LOGIC, embedded in LISP. "LOGLISP: An Alternative to Prolog", J. Alan Robinson et al in Machine Intelligence 10, D. Michie ed, Ellis Horwood 1982.

LOGO - Developed 1966-1968 by a group at Bolt, Beranek & Newman headed by Wally Fuerzeig <> and including Seymour Papert <>. A LISP-like language aimed at children and other beginning programmers, noted for its "turtle graphics" used to draw geometric shapes. Logo interpreters for Mac, Unix, PC, X are available:

LOGOL - Strings are stored on cyclic lists or 'tapes', which are operated upon by finite automata. J. Mysior et al, "LOGOL, A String manipulation Language", in Symbol Manipulations Languages and Techniques, D.G. Bobrow ed, N-H 1968, pp.166-177.

LOLITA - Language for the On-Line Investigation and Transformation of Abstractions. Extension of Culler-Fried system for symbolic math. "An On- line Symbol Manipulation System", F.W. Blackwell, Proc ACM 22nd Natl Conf (1967). Sammet 1969, p.464.

Lolli - (named for the "lollipop" operator "-o") Based on linear logic, in which clauses can be used exactly once. All the operators of lambda- Prolog plus linear variations. Implemented in SML/NJ. Josh Hodas et al, "Logic Programming in a Fragment of Intuitionistic Linear Logic", Information and Computation, to appear.

LOM - Toulouse, early 1980's. Language for data processing.

LOOK - Specification language. "A Look at Algebraic Specifications", S.N. Zilles et al, IBM RR, 1982.


1. "LOOKS: Knowledge-Representation System for Designing Expert Systems in a Logical Programming Framework", F. Mizoguchi, Proc Intl Conf 5th Gen Comp Sys, ICOT 1984.

2. Language for Object-Oriented Kinematics Specifications. E. Peeters <>, 1993. Imperative, object-oriented language for specifying motion. "Design and Implementation of an Object-Oriented Interactive Animation System", Eric Peeters, in Technology of Object- Oriented Languages and Systems, TOOLS 12 & 9, C. Mingins et al eds, P-H 1993, pp.255-267.

LOOPN - U Tasmania. An object-oriented language for simulation of Petri nets.

LOOPS - Lisp Object-Oriented Programming System. Xerox's object-oriented LISP extension, used in development of knowledge-based systems. "The LOOPS Manual", D.G. Bobrow & M. Stefik, Xerox Corp 1983. (See CommonLoops).

LOP - Language based on first-order logic. "SETHEO - A High-Perormance Theorem Prover for First-Order Logic", Reinhold Letz et al, J Automated Reasoning 8(2):183-212 (1992).

Lore -

1. Object-oriented language for knowledge representation. "Etude et Realisation d'un Language Objet: LORE", Y. Caseau, These, Paris-Sud, Nov 1987.

2. CGE, Marcoussis, France. Set-based language [same as 1?] info: Christophe Dony <>

LOTIS - LOgic, TIming, Sequencing. Describes a computer via its data flow. Sammet 1969, p.620.

LOTOS - Specification language based on temporal ordering. "The Formal Description Technique LOTOS", P.H.J. van Eijk et al eds, N-H 1989. ISO 8807 (1990).

Lout - J. Kingson <> Embedded language for the lout document preparation system. Procedural, with Scribe-like syntax. // for Amiga

Low-Ada - An intermediate language for Ada, intended for formal verification. Just a comcept, not yet fully defined or implemented. "Low- Ada: an Ada Validation Tool", B.A. Wichmann, Ada User 11(1): pp.27-32.

LOWL - Abstract machine for bootstrapping ML/1. Mentioned in Machine Oriented Higher Level Languages, W. van der Poel, N-H 1974, p.271.

LPC - ca 1988. Variant of C used to program the LP MUDs, programmable multi-user adventures.


1. Linguaggio Procedure Grafiche (Italian for "Graphical Procedures Language"). dott. Gabriele Selmi. Roughly a cross between FORTRAN and APL, with graphical-oriented extensions and several peculiarities. Underlies the products of CAD.LAB Spa. "Graphical Procedure Language User's Guide and Reference Manual", CAD.LAB , Bologna, Italy, 1989, order code GO89/9.

2. Langage de Programmation Generique. An applicative language, both specification and functional. Special emphasis on parametrized declarations. "Design and Implementation of a Generic, Logic and Functional Programming Language", D. Bert et al, ESOP 86, LNCS 213, Springer 1986.

LPL - List Programming Language. LISP-like language with ALGOL-like syntax, for IBM 360. "LPL - LISP Programming Language", F.W. Blair et al, RC 3062, TJWRC, IBM, Sep 1970.

LPS - Sets with restricted universal quantifiers. "Logic Programming with Sets", G. Kuper, J Computer Sys Sci 41:44-64 (1990).

LRLTRAN - Lawrence Radiation Laboratory TRANslator. FORTRAN extension with vector arithmetic and dynamic storage, used for scientific work and systems programming, including the LTSS OS. "The LRLTRAN Compiler", S.F. Mendicino, CACM 11(11):747-775 (Nov 1969).


1. Larch Shared Language. An assertion language. (See Larch).

2. Link and Selector Language. Graphic query language. "LSL: A Link and Selector Language", D.C. Tsichritzis, Proc Intl Conf Management of Data, ACM 1976, pp.123-134.

LSYD - Language for SYstems Development. PL/I-like language with data structure and character extensions. "Systems Programming Languages", R.D. Bergeron et al, in Advances in Computers 1971, A-P.

LT-2 - Early system on IBM 701. Listed in CACM 2(5):16 (May 1959).

LTR - Langage Temps-Reel. A French predecessor to Ada, Modula-like with a set of special-purpose real-time constructs based on an event model. Mentioned in "An Overview of Ada", J.G.P. Barnes, Soft Prac & Exp 10:851- 887 (1980).

LTR2 -

LTR3 - Parayre, France. Saw wide use by French military and avionics. "The LTR3 Reference Manual", A. Parayre, Delegation Generale pour l'Armement, France.

Lua - TeCGraf, Pontifical Cath U Rio de Janeiro (PUC/Rio), 1994. Pascal- like, functions can have variable number of arguments and return multiple values. Implemented in C, bytecode interpreted. ftp: info: Luiz Henrique de Figueiredo <>


1. Early query language, ca. 1965, System Development Corp, Santa Monica, CA. Sammet 1969, p.701.

2. Ashcroft & Wadge <>, 1981. A dataflow language descended from ISWIM, lazy but first-order. Statements are regarded as equations defining a network of processors and communication lines, through which the data flows. Every data object is thought of as an infinite stream of simple values, every function as a filter. Lucid has no data constructors such as arrays or records. Iteration is simulated with 'is current' and 'fby' (concatenation of sequences). "Lucid, the Dataflow Programming Language", W. Wadge, Academic Press 1985.

Lucinda - Combines Russell-like polymorphism with Linda-like concurrency. Implemented as a threaded interpreter written in C, for a Sun network and a Meiko Computing Surface. "Lucinda - An Overview", P. Butcher, U York <> et al, SIGPLAN Notices 26(8):90-100 (Aug 1991).

Lucy - Distributed constraint programming language. An actor subset of Janus. "Actors as a Special Case of Concurrent Constraint Programming", K. Kahn <> et al, SIGPLAN Notices 25(10):57-66 (OOPSLA/ ECOOP '90) (Oct 1990).

LUKKO - Heinanen, 1983. An object-oriented microprogramming language, influenced by Alphard and Modula. "A Data and Control Abstraction Approach to Microprogramming", J. Heinanen, Publ 18, Tampere U of Tech, Tampere, Finland, 1983.

LUSTRE - Real-time dataflow language for synchronous systems, especially automatic control and signal processing. A Lucid subset, plus timing operators and user-defined clocks. "Outline of a Real-Time Data-Flow Language", J.-L. Bergerand et al, Proc IEE-CS Real Time Systems Symp, San Diego, IEEE Dec 1985, pp.33-42. "LUSTRE: A Declarative Language for Programming Synchronous Systems", P. Caspi et al, Conf Rec 14th Ann ACM Symp on Princ Prog Langs, 1987.

LYaPAS - (Russian acronym for "Logical Language for the Representation of Synthesis Algorithms"). For the URAL-1 computer. Coded in octal! "LYaPAS: A Programming Language for Logic and Coding Algorithms", M.A. Gavrilov et al eds, Academic Press 1969.

LYNX - U Wisc 1984. Language for large distributed networks, using remote procedure calls. "The Lynx Distributed Programming Language: Motivation, Design and Experience", M.L. Scott, Computer Langs 16:209-233 (1991).

LYRIC - Language for Your Remote Instruction by Computer. CAI language implemented as a FORTRAN preprocessor. "Computer Assisted Instruction: Specification of Attributes for CAI Programs and Programmers", G.M. Silvern et al, Proc ACM 21st Natl Conf (1966).