Re: parsability (News Subsystem)
Mon, 9 Feb 2015 14:37:46 +1100

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Related articles
Choosing a parser for Mathematica input (David Kirkby) (2010-11-07)
Re: Choosing a parser for Mathematica input (2015-02-05)
parsability (was: Choosing a parser for Mathematica input) (glen herrmannsfeldt) (2015-02-06)
Re: parsability (Robin Vowels) (2015-02-09)
Re: parsability (Hans-Peter Diettrich) (2015-02-08)
Re: parsability (2015-02-09)
| List of all articles for this month |

From: (News Subsystem)
Newsgroups: comp.compilers
Date: Mon, 9 Feb 2015 14:37:46 +1100
Organization: Compilers Central
References: 10-11-017 15-02-009 15-02-011 15-02-017 15-02-019
Keywords: history, design
Posted-Date: 10 Feb 2015 01:49:07 EST
rFom: "Robin Vowels" <>

From: "Hans-Peter Diettrich" <>
Sent: Monday, February 09, 2015 6:49 AM
> Robin Vowels schrieb:
>> A number of special characters have traditionally acquired multiple uses.
>> The asterisk, parentheses, apostrophe, colon, period, feature heavily
>> on account of the limited number of characters available in equipment
>> of the era (48-character set, 60 character set, etc.) and continue to do so
>> for historical reasons.
> IMO the real and persistent limit is the keyboard, with a limited number
> of keys.

Present keyboards for the PC have keys for 33 special characters
(in addition to upper and lower-case and digits).
That's twice as many in use in languages.

> Increasing the number of keys is not a solution, because then
> it may be more time consuming to find an special key, instead of reusing
> a character or typing more characters.

No need to increase the number of keys. Recall old typewriters?
Some had provision for three shifts (lower-case, upper-case, and special characters).
The same could be done with computer keyboards (well, it's sort of done with the normal, caps, and
CTRL keys).
A proper third shift key with corresponding glyphs inscribed on the keys
could extend the range of special characters. After all, there is provision for 256 characters
encoded in a byte, and we use only half of them.

>Why didn't APL succeed in the long run?

Because it was write once throw-away language.
Programs were largely unintelligible to all except the writer.

This email probably contains viruses and malware despite what avast! Antivirus protection says.
[It was perfectly possible to write readable APL programs, but almost
nobody did. -John]

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