[tex-k] use of $<>$ vs $\ne$ in fancier programs of The METAFONTbook

[胡亚捷 (Hu Yajie)]

(This is an improved version of my report on page 324, lines 2--3.)

The tokens "<>", "<=", and ">=" in "fancier" programs of The METAFONTbook are
sometimes typeset as $<>$, $<=$, $>=$:

Page C119, line 12 (mfbook.tex line 6969)
    $"turningcheck"<=1$.  Plain \MF\ sets $"turningcheck":=2$; the ^@filldraw@
Page C199, line -9 (mfbook.tex line 11457)
    @if@ $.5w<>"good.x"\,.5w$: @change\_width@; @fi@\cr
Page C295, line -10 (mfbook.tex line 15945)
    values $<=0$, but no other information about those values will survive.

and sometimes as $\ne$, $\le$, $\ge$:

Page C105, line 25 (mfbook.tex line 5961)
    character, if we assume that $"slant"\ge0$. Adding $.5u$, subtracting~$w$,
Page C118, line -6 (mfbook.tex line 6947)
    "turningcheck" is $\le0$: If~$q$~is the null pen, path~$p$ is digitized
Page C176, line -8 (mfbook.tex line 10282)
     ^@exitif@ abs$("tx\_"-"fx\_")\le"tolerance"$;\cr
Page C274, line 16 (mfbook.tex line 14806)
    \ (But nothing happens if ^"proofing"$\null\le1$.)
Page C323, line 23 (mfbook.tex line 17461)
    ^"proofing"$\null\ge0$.  A @special@ string should come before
Page C324, lines 2--3 (mfbook.tex lines 17493--6)
    @if@ round $"xoffset"\ne0$: \ @special@ |"xoffset"|; \
     @numspecial@ round ^"xoffset"; @fi@\cr
    @if@ round $"yoffset"\ne0$: \ @special@ |"yoffset"|; \
     @numspecial@ round ^"yoffset"; @fi@\cr
Page C324, line 4 (mfbook.tex line 17500)
    file, if $"proofing"\ge0$, but nothing is output if $"proofing"<0$.
Page C324, line -18 (mfbook.tex line 17536)
    special command is performed at a time when $"proofing"\ge0$, or unless a
Page C324, line -13 (mfbook.tex line 17543)
    based on the current value of~^"hppp". \ (If $"hppp"\le0$, the resolution

Statistics:
                        in programs    in paragraphs
$<>$, $<=$, $>=$                  1                2
$\ne$, $\le$, $\ge$               2                7

My earlier report suggested changing $\ne$ to $<>$, but it turns out the other
way round is better.