Ada explanation?

[Bob Wells #402 <wel@EUROCONTROL.DE>]

G'day,
I was just browsing around the WWW when I came upon "The Free
On-Line Dictionary of Computing." I looked up Ada and found the
following. Perhaps we can give a bit better explanation to the
maintainer of the dictionary.

The dictionary's URL is http://wombat.doc.ic.ac.uk/

Bob W.

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Ada

A Pascal-descended language, designed by Jean Ichbiah's team at CII Honeywell in
1979, made mandatory for Department of Defense software projects by the
Pentagon.

Hackers are nearly unanimous in observing that, technically, it is precisely
what one might expect given that kind of endorsement by fiat; designed by
committee, crockish, difficult to use, and overall a disastrous,
multi-billion-dollar boondoggle (one common description is "The PL/I of the
1980s"). Hackers find Ada's exception handling and inter-process communication
features particularly hilarious.

Ada Lovelace (1811-1852), the daughter of Lord Byron who became the world's
first programmer while cooperating with Charles Babbage on the design of his
mechanical computing engines in the mid-1800s, would almost certainly blanch at
the use to which her name has latterly been put; the kindest thing that has been
said about it is that there is probably a good small language screaming to get
out from inside its vast, elephantine bulk.

Ada is a large, complex block-structured language aimed primarily at embedded
computer applications. It has facilities for real-time response, concurrency,
hardware access and reliable run-time error handling. In support of large-scale
software engineering, it emphasises strong typing, data abstraction and
encapsulation. The type system uses name equivalence and includes both subtypes
and derived types. Both fixed and floating-point numerical types are supported.

Control flow is fully bracketed: if-then-elsif-end if, case-is-when-end case,
loop-exit-end loop, goto. Subprogram parameters are in, out, or inout. Variables
imported from other packages may be hidden or directly visible. Operators may be
overloaded and so may enumeration literals. There are user-defined exceptions
and exception handlers.

An Ada program consists of a set of packages encapsulating data objects and
their related operations. A package has a separately compilable body and
interface. Ada permits generic packages and subroutines, possibly parametrised.
Ada programming places a heavy emphasis on multitasking. Tasks are synchronised
by the rendezvous, in which a task waits for one of its subroutines to be
executed by another. The conditional entry makes it possible for a task to test
whether an entry is ready. The selective wait waits for either of two entries or
waits for a limited time.

See also Ada/Ed, Toy/Ada.

E-mail: adainfo@ajpo.sei.cmu.edu.

FTP, FTP, FTP.

An Ada grammar including a lex scanner and yacc parser is available. E-mail:
compilers-server@iecc.cambridge.ma.us, masticol@dumas.rutgers.edu.

Another yacc grammar and parser for Ada by Herman Fischer is here.

An LR parser and pretty-printer for Ada from NASA is available from the Ada
Software Repository. Michael Feldman <mfeldman@seas.gwu.edu> referred to this
package in comp.compilers, he also has a yacc grammar for ada.

Adamakegen generates makefiles for Ada programs.

["Reference Manual for the Ada Programming Language", ANSI/MIL STD 1815A, US DoD
(Jan 1983)]. Earlier draft versions appeared in July 1980 and July 1982. ISO
1987.

(08 Nov 1994)


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