[DFDL-WG] Zoned decimals: spec errata 2.92 & 2.88

[Steve Hanson]

2.92. Section 13.6. When property textNumberRep is ‘zoned’, the property 
description should state that ‘zoned’ is only allowed for SBCS encodings 
(schema definition error otherwise). 

When I came to implement this for IBM DFDL, I noticed there were already 
tests for UTF-8 and Shift_JIS which succeeded. The point being that both 
these character sets are ASCII compatible for the first 128 code points 
(Shift_JIS has two code points that differ, x5C and x7E).  I am wondering 
if this errata is therefore too strict?  I am particularly concerned that 
there might be Japanese users who will have COBOL data in Shift_JIS or 
MS_Kanji.


2.88. Section 13.5. Add support for HP NonStop Tandem zoned decimals. In 
this architecture, the negative sign is incorporated in the last byte of 
the number in the usual manner, but the overpunching occurs on the highest 
bit (ie, value 8) of the nibble. Consequently, a new enum value 
'asciiTandemModified’ is added to property textZonedSignStyle.
 
The range of ASCII code points that are used in a zoned number is x30-x39 
and either x70-x79 (standard overpunch) or x7B, x41-x49 (translated EBCDIC 
overpunch) or x20-x29 (CA Realia overpunch). This errata adds x80-x89. But 
these are not code points in standard ASCII, so the modeller must specify 
something like ISO-8859-1 in order for this to parse without an encoding 
error. The wording in the spec for this errata alludes to this but could 
make this clearer.
asciiTandemModified: In this style the ascii characters ‘0-9’ represent 
positive sign and digits 0 to 9, but bytes from 0x80 to 0x89 are used to 
represent overpunched negative sign and a digit. There are no 
corresponding character codepoints in the standard ASCII encoding since 
these values are all above 128 (decimal). (Note that neither ISO-8859-1 
encoding nor Unicode have assigned glyphs for these codepoints. They are 
considered control characters.)

Regards

Steve Hanson
Architect, IBM Data Format Description Language (DFDL)
Co-Chair, OGF DFDL Working Group
IBM SWG, Hursley, UK
smh at uk.ibm.com
tel:+44-1962-815848
Unless stated otherwise above:
IBM United Kingdom Limited - Registered in England and Wales with number 
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Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6 3AU

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