Re: Why no numbers allowed in variables?

[J Martin Rushton]

On 02/10/18 23:25, David Kastrup wrote:
> J Martin Rushton <address@hidden> writes:
> 
>> This discussion is strangely familiar.  As one who learnt on FORTRAN IV
>> many years ago, I'm used to seeing that:
>>
>> READ INPUT TAPE 5, 501, IA, IB, IC
>> and
>> READINPUTTAPE5,501,IA,IB,IC
>> or even
>> RE ADIN PUTTA PE5,5 01,I A,I B,I C
>>
>> are the same.  I'm sure there were those back in the late '50s arguing
>> over the use of spaces and numbers within variables.
>>
>> (OT) I've even seen code which intentionally mangled FORTRAN source to
>> make it unreadable, like the third example above.
> 
> That's more like making spaces not have any lexical meaning, ever.
> Basically, if it cannot be part of an identifier, it also cannot
> separate them.  Also you have to be aware that a fresh punch card is
> both empty and contains 80 spaces.  Basically spaces are not even
> recognizable characters in the original typical Fortran input medium.
> 
> For TeX it was more the decision to be able to write things like
> 
> \count5=7
> 
> and LilyPond input is very very loosely modeled after that (via MusicTeX
> and MPP).
> 
Quite correct.  Early FORTRAN compilers eliminated all spaces (other
than those in Hollerith strings) and then parsed the resultant mess.
-- 
J Martin Rushton MBCS

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