Proposal: Document use of control characters
Murray Maloney <murray@oclc.org>
Date: Thu, 16 Jun 94 12:20:40 EDT
Message-id: <9406161206.aa11328@dali.scocan.sco.COM>
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From: Murray Maloney <murray@oclc.org>
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Subject: Proposal: Document use of control characters
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Proposal: Identify the control characters in ISO 8859/1
that are recognized as valid HTML. identify those
control characters which are not valid by specifying
them as SHUNCHARs in the SGML declaration, and document
them in the HTML specification. For each control character
that is valid, identify its meaning and potential uses.
For all control characters which are not valid, list
the characters and their codes, and specify the error
(if any) which may result if the character is discovered.
Some background...
The character set for ISO 8859/1 Latin alphabet No 1
includes characters from most Western European languages.
It consists of the space character, 186 characters
that form a subset of the graphic characters
in ISO 6937/2 (1983), and four additional characters
that are intended for inclusion in ISO 6937/2.
The standard specifically states that control characters
are beyond the scope of ISO 8859/1. However, in practice,
reference to thsi character set includes reference
to the control characters that are specified in
ISO 646, ISO 6429, and the ASCII character sets.
The following two characters fall within 8859/1.
Their behaviour should be specified in the standard.
160 nbsp no-break space
173 shy soft hyphen
There are also several character positions which are unassigned.
The character positions in question are (in decimal):
128 UNNASSIGNED
129 UNNASSIGNED
130 UNNASSIGNED
131 UNNASSIGNED
132 ind index
133 nel next line
134 ssa start of selected area
135 esa end of selected area
136 hts horizontal tab set
137 htj horizontal tab with justification
138 vts vertical tab set
139 pld partial line down
140 plu partial line up
141 ri reverse index
142 ss2 single shift 2
143 ss3 single shift 3
144 dcs device control string
145 pu1 private use 1
146 pu2 private use 2
147 sts set transmit state
148 cch cancel character
149 mw message waiting
150 spa start of guarded protected area
151 epa end of guarded protected area
152 UNNASSIGNED
153 UNNASSIGNED
154 UNNASSIGNED
155 csi control sequence character
156 st ???
157 osc operating system command
158 pm privacy message
159 apc application program command
216 UNASSIGNED