Re: Terminal Graphics Draft 2

From: John Cowan (cowan@locke.ccil.org)
Date: Thu Oct 08 1998 - 15:09:44 EDT


Frank da Cruz wrote:

> NEL stands for Next Line (not Newline). The definition of NEL
> in ISO 6429 [8.3.87] is rather complex: "The effect of NEL
> depends on the setting of the DEVICE COMPONENT SELECT MODE
> (DCSM) and on the parameter value of SELECT IMPLICIT MOVEMENT
> DIRECTION (SIMD)." Several paragraphs go on to explain this.

The purpose of NEL and its fraternal twin IND (Index) was to
separate the multiple semantics of LF. LF could mean either
advance-to-next line or advance-to-start-of-next-line (the semantics
adopted by Unix). IND was given the first semantics, and
NEL the second. So representing a NEL by the SYMBOL FOR NEWLINE
character is quite reasonable.

But the SYMBOL FOR NEWLINE is not tied to U+2424, which is a LINE
SEPARATOR, not a line terminator. A typical (though not the only)
glyph for U+2424 is the one which appears on the Enter key of PC
keyboards.

-- 
John Cowan	http://www.ccil.org/~cowan		cowan@ccil.org
	You tollerday donsk?  N.  You tolkatiff scowegian?  Nn.
	You spigotty anglease?  Nnn.  You phonio saxo?  Nnnn.
		Clear all so!  'Tis a Jute.... (Finnegans Wake 16.5)



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