opal 音標拼音: ['opəl]
n . 蛋白石,貓眼石
蛋白石,貓眼石
opal n 1 :
a translucent mineral consisting of hydrated silica of variable color ;
some varieties are used as gemstones Opal \
O "
pal \,
n . [
L .
opalus :
cf .
Gr . ?,
Skr .
upala a rock ,
stone ,
precious stone :
cf .
F .
opale .] (
Min .)
A mineral consisting ,
like quartz ,
of silica ,
but inferior to quartz in hardness and specific gravity .
[
1913 Webster ]
Note :
The {
precious opal }
presents a peculiar play of colors of delicate tints ,
and is highly esteemed as a gem .
One kind ,
with a varied play of color in a reddish ground ,
is called the {
harlequin opal }.
The {
fire opal }
has colors like the red and yellow of flame . {
Common opal }
has a milky appearance . {
Menilite }
is a brown impure variety ,
occurring in concretions at Menilmontant ,
near Paris .
Other varieties are {
cacholong }, {
girasol },
{
hyalite },
and {
geyserite }.
[
1913 Webster ]
1 .
A {
DSP }
language .
["
OPAL :
A High Level Language and Environment for DSP boards
on PC ",
J .
P .
Schwartz et al ,
Proc ICASSP -
89 ,
1989 ].
2 .
The language of the {
object -
oriented database } {
GemStone }.
["
Making Smalltalk a Database System ",
G .
Copeland et al ,
Proc
SIGMOD '
84 ,
ACM 1984 ,
pp .
316 -
325 ].
3 .
A {
simulation }
language with provision for {
stochastic
variables }.
An extension of {
Autostat }.
["
C -
E -
I -
R OPAL ",
D .
Pilling ,
Internal Report ,
C .
E .
I .
R .
Ltd . (
1963 )].
4 .
A language for compiler testing said to be used internally
by {
DEC }.
5 .
A {
functional programming }
language designed at the
{
Technische Universitaet Berlin }
as a testbed for the
development of {
functional programs }.
OPAL integrates
concepts from Algebraic Specification and Functional
Programming ,
which favour the (
formal )
development of (
large )
production -
quality software written in a {
purely functional }
style .
The core of OPAL is a {
strongly typed }, {
higher -
order },
{
strict }
applicative language which belongs to the tradition
of {
Hope }
and {
ML }.
The algebraic flavour of OPAL is visible
in the syntactical appearance and in the preference of
{
parameterisation }
to {
polymorphism }.
OPAL supports : {
information hiding } -
each language unit is
divided into an interface (
signature )
and an implementation
part ;
selective import ; {
parameterised modules };
free
constructor {
views }
on {
sorts },
which allow pattern -
based
function definitions despite quite different implementations ;
full {
overloading }
of names ;
puristic scheme language with no
{
built -
in }
data types (
except {
Booleans }
and denotations ).
OPAL and its predecessor OPAL -
0 have been used for some time
at the Technische Universitaet Berlin in CS courses and for
research into optimising compilers for applicative languages .
The OPAL compiler itself is writte entirely in OPAL .
An overview is given in "
OPAL :
Design And Implementation of an
Algebraic Programming Language ".
{(
http ://
cs .
tu -
berlin .
de /~
opal /)}.
{(
ftp ://
ftp .
cs .
tu -
berlin .
de /
pub /
local /
uebb /
papers /
DesignImplOpal .
ps .
gz )}.
(
1995 -
02 -
16 )
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