banks@viking.dec.com (07/26/86)
In regard to the non-controversy over the ANSI sequences for Erase in Line
and Erase in Display, quoting from pages 35 and 36 from ANSI standard
X3.64-1979:
5.29 ED ERASE IN DISPLAY
(Editor function; format: CSI Ps F; default value: 3/0)
Erases some or all of the characters in the display according to the parameter.
Param. Parameter Meaning
3/0 FROM ACTIVE POSITION TO END INCLUSIVE (DEFAULT)
3/1 FROM START TO ACTIVE POSITION INCLUSIVE
3/2 ALL OF DISPLAY
Whether unprotected areas or all areas are erased depends on the reset or
set state of the Erasure More (ERM). Character positions outside of the
current display may be affected if the Editing Boundary Mode (EBM) is in
the set state.
...
5.31 EL ERASE IN LINE
(Editor function; format: CSI Ps F; default value: 3/0)
Erases some or all of the characters in the active line according to the
parameter.
Param. Parameter Meaning
3/0 FROM ACTIVE POSITION TO END INCLUSIVE (DEFAULT)
3/1 FROM START TO ACTIVE POSITION INCLUSIVE
3/2 ALL OF LINE INCLUSIVE
Whether unprotected areas are erased depends on the reset or set state of
Erasure Mode (ERM). Character positions outside the current display may be
affected if the Editing Boundary Mode (EBM) is in set state.
---
Or, to translate, CSI 1 J, CSI 2 J, CSI 1 K, CSI 2 K are both defined and
supported by ANSI standard X3.64, which is the standard that so called
"ANSI" terminals adhere to. They are NOT VT-100 or Digital private sequences.
In fact, the VT-100/Digital private sequences all adhere to the guidelines
in X3.64 for proprietary sequences, so you can tell by looking at the
sequence whether it's DEC proprietary. Paraphrasing the spec for a moment,
the way you can tell that it's a proprietary sequence is if it fits one of
the following conditions:
o the character immediately following the CSI is one of < = > ?
o the final character is in the range 7/0 thru 7/14 inclusive,
meaning the characters p q r s t u v w x y z { | } ~
I personally know of no DEC private sequence that violates those rules.
* SMALL FLAME *
I don't really know what purpose is served saying that you don't have to
implement DEC private escape sequences, especially given that so much
software in the world that assumes ANSI compatibility is really assuming
VT-100 compatibility. Certainly, no one has to implement all of the
DEC private sequences to be an ANSI device, but doing so makes life for
the rest of us so much easier.
* end small flame, begin inflammatory disclaimer *
Although I work for Digital Equipment Corp, I do not have any affiliation
with any of their Terminal products. My opinions are strictly my own, and
in no way reflect those of any department within my employer's organization.
Most of the time, they just want me to shut up and go away anyway.
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