Errors in TUS Figure 15.2?

From: Peter Kirk (
Date: Fri Jul 30 2004 - 09:06:29 CDT

  • Next message: Otto Stolz: "Re: Errors in TUS Figure 15.2?"

    There appear to be two errors (not listed in the errata page in Figure 15.2 on page 391 of The
    Unicode Standard 4.0, the online version at

    The fourth and last column of the table appears to be the same as the
    third column, except for the header row and the first content row
    referring to the fi ligature. But the forms in the second and third rows
    seem to be incorrect. (The forms in the fourth row should be the same.)

    The fourth column is supposed to indicate the desired rendering of <C1,
    ZWJ, C2>. But in the text just before, ZWJ is specified as follows:

    > ZWJ requests that glyphs in the highest available category (for the
    > given font) be used:
    > 1. Unconnected
    > 2. Cursively connected
    > 3. Ligated

    The forms in the fourth column of the figure, for <lam, ZWJ, alef> and
    <meem, ZWJ, jeem> are apparently cursively connected forms, but they are
    not the ligatures which appear in the first column of the table. The
    first column shows that there are ligatures available in the font, and
    by the rules for ZWJ these ligatures should be selected by these
    sequences. The correct way of selecting the cursively connected but not
    ligated forms which are shown is to insert <ZWJ, ZWNJ, ZWJ> as in the
    third column. So the forms in the fourth column should be corrected to
    be the ligature forms already shown in the first column.

    There also seems to be an error in the text just before the figure which
    states "In the Arabic examples, the characters on the left side are in
    visual order already, but have not yet been shaped." In fact they have
    been shaped, at least in the second and third rows - no shaping applies
    (by default) to the fourth row.

    Am I correct that there are errors here?

    Ah, now I see the following paragraph. But if this paragraph is intended
    to modify the definition of ZWJ already given, it should be part of the
    specification, rather than being given after the examples, and
    specifically the examples which illustrates it. And this does not
    explain the error in the text.

    PS to John Hudson: The second row of this figure is an example of how
    <C1, C2>, <C1, ZWJ, C2> and <C1, ZWNJ, C2> must have three separate
    renderings, something which you told me (on the Hebrew list) was
    impossible both conceptually and with current rendering engines.

    Peter Kirk (personal) (work)

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