Re: Ada versus Pascal

[Dennis Lee Bieber <wlfraed@ix.netcom.com>]

On Thu, 21 Oct 2021 22:29:15 -0500, 711 Spooky Mart <711@spooky.mart>
declaimed the following:

>The little snippets of Ada code I've seen look _alot_ like Pascal.
>
	No surprise. The teams that took part in the DoD competition to design
a language to replace the mish-mash of languages being used in the 70s
tended to choose Pascal as the starting point (Modula-2 hadn't escaped
ETH-Zurich yet <G>).

	The main difference is that Ada incorporated block closing syntax at
the base, finding Pascal (and C) [begin/end, {/} respectively] usage
error-prone (dangling else, etc.) along with using ; as a terminator
instead of separator. Oh, and using (/) for both function arguments and
array indexing (back then, most US keypunches didn't support [/] or {/} ).

	Declarations do not have a defined sequence (type, constant, variable).

	Also, Pascal of the era typically did not support separate compilation
and/or include files -- programs were all single monolithic files, any
change required recompiling the entire program.

	Pascal also had a relatively limited I/O system -- with the bad quirk
that it did "pre-reads" of files. Made interactive/console programs
difficult (or required special handling by the run-time startup) --
starting a program would result in stdin reading at the least one
character, if not one line, into the file buffer variable... But the
program may not want the data until after lots of initialization and
prompts.

>What degree of learning curve is there to learn Ada, coming from a
>Pascal background? What kind of rough timeframes to get comfortable with
>programming without always looking to the manuals?
>
	If all one is writing is "Pascal" type applications, without using
complex data types (ie; defining specific types for each "concept") -- it
shouldn't take too long.

	Tasking, rendezvous, protected objects (not to be confused with private
objects), and generics, may take longer to get comfortable with.

	The appendices of the LRM will tend to get lots of usage; there are
many subtleties to the standard libraries.


-- 
	Wulfraed                 Dennis Lee Bieber         AF6VN
	wlfraed@ix.netcom.com    http://wlfraed.microdiversity.freeddns.org/