Lucid

[loo-sid] /ˈlu sɪd/

adjective
1.
easily understood; completely intelligible or comprehensible:
a lucid explanation.
2.
characterized by clear perception or understanding; rational or sane:
a lucid moment in his madness.
3.
shining or bright.
4.
clear; pellucid; transparent.
/ˈluːsɪd/
adjective
1.
readily understood; clear
2.
shining or glowing
3.
(psychiatry) of or relating to a period of normality between periods of insane or irresponsible behaviour
adj.

1590s, “bright, shining,” from Latin lucidus “light, bright, clear,” figuratively “perspicuous, lucid, clear,” from lucere “to shine,” from lux (genitive lucis) “light,” from PIE root *leuk- “to shine, be bright” (see light (n.)). Sense of “easy to understand” first recorded 1786. Lucid interval “period of calm or temporary sanity” (1580s) is from Medieval Latin lucida intervalla (plural), which was common in medieval English legal documents (cf. non est compos mentis, sed gaudet lucidis intervallis). Related: Lucidly; lucidness (1640s).

1. Early query language, ca. 1965, System Development Corp, Santa Monica, CA. [Sammet 1969, p.701].
2. A family of dataflow languages descended from ISWIM, lazy but first-order.
Ashcroft & Wadge , 1981.
They use a dynamic demand driven model. 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). Higher-order functions are implemented using pure dataflow and no closures or heaps.
[“Lucid: The Dataflow Language” by Bill Wadge [email protected] and Ed Ashcroft, c. 1985]. [“Lucid, the Dataflow Programming Language”, W. Wadge, Academic Press 1985].
(1995-02-16)