@Section
    @Tag { dia_summ }
    @Title { Summary }
@Begin
@PP
Here is the complete list of standard node outlines that may be given
diagrams. @RawIndex { diagrams }
diagrams.summary @SubIndex { summary of all options }
summary.diagrams @Index { summary of all options for diagrams }
to the @Code "@Node" symbol.  Each shows the outline name, any extra
options relevant to this outline, base (shown as a grey
box), segments (shown using {@Code "outlinestyle { solid dashed }"}),
tags, and directions (shown as a thick arrowhead wherever defined):
@IndentedList gap { 3v }

@LI {
@Code {
"@Node"
"    outline { box }"
}
||7ct
@Diag {
//0.5f
@Box paint { lightgrey } outlinestyle { noline } margin { 0c }
@ShowTags @ShowDirections @Node
    outline { box }
    outlinestyle { solid dashed }
    outlinewidth { 0.03f }
    vsize { 1.0c } hsize { 2.0c }
}
}

@LI {
@Code {
"@Node"
"    outline { curvebox }"
}
||7ct
@Diag {
@Box paint { lightgrey } outlinestyle { noline } margin { 0c }
@ShowTags @ShowDirections @Node
    outline { curvebox }
    outlinestyle { solid dashed }
    outlinewidth { 0.03f }
    vsize { 1.0c } hsize { 2.0c }
}
}

@LI {
@Code {
"@Node"
"    outline { shadowbox }"
"    shadow { 0.4f }"
}
||7ct
@Diag {
@Box paint { lightgrey } outlinestyle { noline } margin { 0c }
@ShowTags @ShowDirections @Node
    outline { shadowbox }
    outlinestyle { solid dashed }
    outlinewidth { 0.03f }
    vsize { 1.0c } hsize { 2.0c }
}
}

@LI {
@Code {
"@Node"
"    outline { square }"
}
||7ct
@Diag {
//1.5f
@Box paint { lightgrey } outlinestyle { noline } margin { 0c }
@ShowTags @ShowDirections @Node
    outline { square }
    outlinestyle { solid dashed }
    outlinewidth { 0.03f }
    vsize { 1.0c } hsize { 2.0c }
}
}

@LI {
@Code {
"@Node"
"    outline { diamond }"
}
||7ct
@Diag {
@Box paint { lightgrey } outlinestyle { noline } margin { 0c }
@ShowTags @ShowDirections @Node
    outline { diamond }
    outlinestyle { solid dashed }
    outlinewidth { 0.03f }
    vsize { 1.0c } hsize { 2.0c }
}
}

@LI {
@Code {
"@Node"
"    outline { polygon }"
"    sides { 3 }"
"    angle { 180d / sides }"
}
||7ct
@Diag {
//0.5f
@Box paint { lightgrey } outlinestyle { noline } margin { 0c }
@ShowTags @ShowDirections @Node
    outline { polygon }
    outlinestyle { solid dashed }
    outlinewidth { 0.03f }
    vsize { 1.0c } hsize { 2.0c }
&0.5c ... &0.5c
@Box paint { lightgrey } outlinestyle { noline } margin { 0c }
@ShowTags @ShowDirections @Node
    outline { polygon }
    sides { 10 }
    outlinestyle { solid dashed }
    outlinewidth { 0.03f }
    vsize { 1.0c } hsize { 2.0c }
&0.5c ...
}
}

@LI {
@Code {
"@Node"
"    outline { isosceles }"
}
||7ct
@Diag {
@Box paint { lightgrey } outlinestyle { noline } margin { 0c }
@ShowTags @ShowDirections @Node
    outline { isosceles }
    outlinestyle { solid dashed }
    outlinewidth { 0.03f }
    vsize { 1.0c } hsize { 2.0c }
}
}

@LI {
@Code {
"@Node"
"    outline { ellipse }"
}
||7ct
@Diag {
@Box paint { lightgrey } outlinestyle { noline } margin { 0c }
@ShowTags @ShowDirections @Node
    outline { ellipse }
    outlinestyle { solid dashed }
    outlinewidth { 0.03f }
    vsize { 1.0c } hsize { 2.0c }
}
}

@LI {
@Code {
"@Node"
"    outline { circle }"
}
||7ct
@Diag {
@Box paint { lightgrey } outlinestyle { noline } margin { 0c }
@ShowTags @ShowDirections @Node
    outline { circle }
    outlinestyle { solid dashed }
    outlinewidth { 0.03f }
    vsize { 1.0c } hsize { 2.0c }
}
}

@EndList
@DP
Here are the abbreviations for the standard shapes:
@ID @Tab
    vmargin { 0.5vx }
    @Fmta { @Col @Code { outline "{" A "}" } ! @Col @Code { "@"B } }
{
@Rowa
    A { box }
    B { Box }
@Rowa
    A { curvebox }
    B { CurveBox }
@Rowa
    A { shadowbox }
    B { ShadowBox }
@Rowa
    A { square }
    B { Square }
@Rowa
    A { diamond }
    B { Diamond }
@Rowa
    A { polygon }
    B { Polygon }
@Rowa
    A { isosceles }
    B { Isosceles }
@Rowa
    A { ellipse }
    B { Ellipse }
@Rowa
    A { circle }
    B { Circle }
}
Here are all the options to the @Code "@Node" symbol, their default
values, and their ranges of allowed values.  Definitions of {@I number},
{@I length}, {@I angle}, and {@I point} appear later in this summary.  The
options related to {@Code alabel}, {@Code blabel}, {@Code clabel}, and
{@Code dlabel} have mostly been omitted since they are the same as
the {@Code nodelabel} options except for {@Code nodelabelpos}.
@DP
1fx @Break @Tab
  hmargin { 1s }
  # vmargin { 0.6vx }
  @Fmth { @Col @Code A ! @Col @Code " " ! @Col @Code B ! @Col @Code " " !
	  @Col 0.3c @Wide ! @Col C }
  @Fmta { @Col @Code A ! @Col @Code "{" ! @Col @Code B ! @Col @Code "}" !
	  @Col 0.3c @Wide ! @Col C }
{
@FirstRowh
  A { "@Node" }
@Rowa
  A { "   outline" }
  B { box }
  C { {@Code box}, {@Code curvebox}, {@Code shadowbox}, {@Code square},
{@Code diamond}, {@Code polygon}, {@Code ellipse}, {@Code circle}, or
any outline }
@Rowa
  A { "   margin"    }
  B { 0.6f }
  C { any length from Section {@NumberOf objects} }
@Rowa
  A { "   shadow"    }
  B { 0.4f }
  C { any @I length }
@Rowa
  A { "   sides"    }
  B { 3 }
  C { any @I number (it will be rounded to the nearest integer) }
@Rowa
  A { "   angle"    }
  B { 180d "/" sides }
  C { any @I angle }
@Rowa
  A { "   translate"    }
  B { }
  C { empty, or @I point @Code to @I point }
@Rowa
  A { "   outlinestyle" }
  B { solid }
  C { {@Code solid}, {@Code dashed}, {@Code cdashed}, {@Code dotted},
{@Code dotdashed}, {@Code dotcdashed}, {@Code dotdotdashed},
{@Code dotdotcdashed}, {@Code dotdotdotdashed}, {@Code dotdotdotcdashed},
{@Code noline}, or any sequence of one or more of these }
@Rowa
  A { "   outlinedashlength"}
  B { 0.2f }
  C { any @I length }
@Rowa
  A { "   outlinewidth" }
  B { thin }
  C { {@Code thin}, {@Code medium}, {@Code thick}, or any @I length }
@Rowa
  A { "   outlinecolour" }
  B { nochange }
  C { @Code nochange or any colour from  Section {@NumberOf colour} }
@Rowa
  A { "   paint"     }
  B { none }
  C { @Code none or any colour from Section {@NumberOf colour} }
@Rowa
  A { "   texture"     }
  B { solid }
  C { Any texture from Section {@NumberOf textures} }
@Rowa
  A { "   font"     }
  B { }
  C { any value suitable for the @Code "@Font" symbol }
@Rowa
  A { "   break"     }
  B { }
  C { any value suitable for the @Code "@Break" symbol }
@Rowa
  A { "   format"     }
  B { "@Body" }
  C { any object, usually containing {@Code "@Body"} }
@Rowa
  A { "   valign"}
  B { ctr }
  C { {@Code "top"}, {@Code "ctr"}, {@Code "foot"}, or any length
from Section {@NumberOf objects} }
@Rowa
  A { "   vsize"}
  B { }
  C { empty, or any length from Section {@NumberOf objects} }
@Rowa
  A { "   vindent"}
  B { ctr }
  C { {@Code "top"}, {@Code "ctr"}, {@Code "mctr"}, {@Code "foot"}, or any
length from Section {@NumberOf objects} }
@Rowa
  A { "   vstrut"}
  B { no }
  C { {@Code no}, {@Code yes}, or any length from Section {@NumberOf objects} }
@Rowa
  A { "   vmargin"    }
  B { margin }
  C { any length from Section {@NumberOf objects} }
@Rowa
  A { "   topmargin"    }
  B { vmargin }
  C { any length from Section {@NumberOf objects} }
@Rowa
  A { "   footmargin"    }
  B { vmargin }
  C { any length from Section {@NumberOf objects} }
@Rowa
  A { "   halign"}
  B { ctr }
  C { {@Code "left"}, {@Code "ctr"}, {@Code "right"}, or any length from Section {@NumberOf objects} }
@Rowa
  A { "   hsize"}
  B { }
  C { empty, or any length from Section {@NumberOf objects} }
@Rowa
  A { "   hindent"}
  B { ctr }
  C { {@Code "left"}, {@Code "ctr"}, {@Code "mctr"}, {@Code "right"}, or any
length from Section {@NumberOf objects} }
@Rowa
  A { "   hstrut"}
  B { no }
  C { {@Code no}, {@Code yes}, or any length from Section {@NumberOf objects} }
@Rowa
  A { "   hmargin"    }
  B { margin }
  C { any length from Section {@NumberOf objects} }
@Rowa
  A { "   leftmargin"    }
  B { hmargin }
  C { any length from Section {@NumberOf objects} }
@Rowa
  A { "   rightmargin"    }
  B { hmargin }
  C { any length from Section {@NumberOf objects} }
@Rowa
  A { "   nodelabel"}
  B {  }
  C { any object }
@Rowa
  A { "   nodelabelmargin"}
  B { 0.2f }
  C { any length from Section {@NumberOf objects} }
@Rowa
  A { "   nodelabelfont"}
  B { -2p }
  C { any value suitable for the @Code "@Font" symbol }
@Rowa
  A { "   nodelabelbreak"}
  B { ragged nohyphen }
  C { any value suitable for the @Code "@Break" symbol }
@Rowa
  A { "   nodelabelformat"}
  B { "@Body" }
  C { any object, usually containing @Code "@Body" }
@Rowa
  A { "   nodelabelpos"}
  B { }
  C { any @I point }
@Rowa
  A { "   nodelabelangle"}
  B { horizontal }
  C { {@Code horizontal}, {@Code aligned}, or {@Code perpendicular};
{@Code parallel}, {@Code antiparallel}, or any @I angle }
@Rowa
  A { "   nodelabelprox"}
  B { outside }
  C { {@Code above}, {@Code below}, {@Code left}, {@Code right},
{@Code inside}, or {@Code outside}; {@Code CTR}, {@Code N}, {@Code S},
{@Code E}, {@Code W}, {@Code NE}, {@Code NW}, {@Code SW}, {@Code SE},
{@Code NNW}, {@Code NNE}, {@Code SSW}, or {@Code SSE}
}
@Rowa
  A { "   nodelabelctr"}
  B { no }
  C { @Code yes or @Code no }
@Rowa
  A { "   nodelabeladjust"}
  B { 0 0 }
  C { any @I point }
@Rowa
  A { "   alabelpos"}
  B { NE }
  C { any @I point }
@Rowa
  A { "   blabelpos"}
  B { NW }
  C { any @I point }
@Rowa
  A { "   clabelpos"}
  B { SW }
  C { any @I point }
@Rowa
  A { "   dlabelpos"}
  B { SE }
  C { any @I point }
}
@DP
Here is the complete list of standard link paths that may be given
to the @Code "@Link" symbol.  Each entry shows the link path name,
any extra options relevant to this path, segments (shown using
{@Code "outlinestyle { solid dashed }"}, and tags.  All tags
have directions pointing along the link from @Code FROM to
{@Code TO}; these have been omitted for clarity.  The @Code frompt
and @Code topt options of @Code bezier are compulsory and denote the
two control points (Section {@NumberOf dia_defi}).
@IndentedList gap { 2v }

@LI {
@Code {
"@Link"
"    path { line }"
}
||6ct
@Diag {
//0.5f
A:: @Circle /0.8c |1.5c B:: @Circle 
//
@ShowTags @Link
    pathstyle { solid dashed }
    path { line } from { A } to { B }
}
&2.5c
#@Diag {
#|1.5c B:: @Circle /0.8c A:: @Circle 
#//
#@ShowTags @Link
#    pathstyle { solid dashed }
#    path { line } from { A } to { B }
#}
}

@LI {
@Code {
"@Link"
"    path { doubleline }"
}
||6ct
@Diag {
//0.5f
A:: @Circle /0.8c |1.5c B:: @Circle 
//
@ShowTags @Link
    pathstyle { solid dashed }
    path { doubleline } from { A } to { B }
}
&2.5c
#@Diag {
#|1.5c B:: @Circle /0.8c A:: @Circle 
#//
#@ShowTags @Link
#    pathstyle { solid dashed }
#    path { line } from { A } to { B }
#}
}

@LI {
@Code {
"@Link"
"    path { curve }"
"    bias { 2.0f }"
}
||6ct
@Diag {
A:: @Circle /0.8c |1.5c B:: @Circle 
//
@ShowTags @Link
    pathstyle { solid dashed }
    path { curve } from { A } to { B }
}
&2.5c
@Diag {
|1.5c B:: @Circle /0.8c A:: @Circle 
//
@ShowTags @Link
    pathstyle { solid dashed }
    path { curve } from { A } to { B }
}
}

@LI {
@Code {
"@Link"
"    path { ccurve }"
"    bias { 2.0f }"
}
||6ct
@Diag {
//0.5f
A:: @Circle /0.8c |1.5c B:: @Circle 
//
@ShowTags @Link
    pathstyle { solid dashed }
    path { ccurve } from { A } to { B }
}
&2.5c
@Diag {
//0.5f
|1.5c B:: @Circle /0.8c A:: @Circle 
//
@ShowTags @Link
    pathstyle { solid dashed }
    path { ccurve } from { A } to { B }
}
}

@LI {
@Code {
"@Link"
"    path { bezier }"
"    frompt { A@CTR ++ { 3f 0 } }"
"    topt { B@CTR ++ { 3f 0 } }"
}
||6ct
@Diag {
//0.5f
A:: @Circle /0.8c |1.5c B:: @Circle 
//
@ShowTags @Link
    pathstyle { solid dashed }
    path { bezier } from { A } to { B }
    frompt { A@CTR ++ { 3f 0 } }
    topt { B@CTR ++ { 3f 0 } }
}
&2.5c
@Diag {
//0.5f
|1.5c B:: @Circle /0.8c A:: @Circle 
//
@ShowTags @Link
    pathstyle { solid dashed }
    path { bezier } from { A } to { B }
    frompt { A@CTR ++ { 3f 0 } }
    topt { B@CTR ++ { 3f 0 } }
}
}

@LI {
@Code {
"@Link"
"    path { vhline }"
}
||6ct
@Diag {
//0.5f
A:: @Circle /0.8c |1.5c B:: @Circle 
//
@ShowTags @Link
    pathstyle { solid dashed }
    path { vhline } from { A } to { B }
}
&2.5c
@Diag {
//0.5f
|1.5c B:: @Circle /0.8c A:: @Circle 
//
@ShowTags @Link
    pathstyle { solid dashed }
    path { vhline } from { A } to { B }
}
}

@LI {
@Code {
"@Link"
"    path { hvline }"
}
||6ct
@Diag {
//0.5f
A:: @Circle /0.8c |1.5c B:: @Circle 
//
@ShowTags @Link
    pathstyle { solid dashed }
    path { hvline } from { A } to { B }
}
&2.5c
@Diag {
//0.5f
|1.5c B:: @Circle /0.8c A:: @Circle 
//
@ShowTags @Link
    pathstyle { solid dashed }
    path { hvline } from { A } to { B }
}
}

@LII {
In the following links, the @Code radius option determines the
radius of the curved corners of the link.
}

@LI {
@Code {
"@Link"
"    path { vhcurve }"
"    radius { 1.0f }"
}
||6ct
@Diag {
//0.5f
A:: @Circle /0.8c |1.5c B:: @Circle 
//
@ShowTags @Link
    pathstyle { solid dashed }
    path { vhcurve } from { A } to { B }
}
&2.5c
@Diag {
//0.5f
|1.5c B:: @Circle /0.8c A:: @Circle 
//
@ShowTags @Link
    pathstyle { solid dashed }
    path { vhcurve } from { A } to { B }
}
}

@LI {
@Code {
"@Link"
"    path { hvcurve }"
"    radius { 1.0f }"
}
||6ct
@Diag {
//0.5f
A:: @Circle /0.8c |1.5c B:: @Circle 
//
@ShowTags @Link
    pathstyle { solid dashed }
    path { hvcurve } from { A } to { B }
}
&2.5c
@Diag {
//0.5f
|1.5c B:: @Circle /0.8c A:: @Circle 
//
@ShowTags @Link
    pathstyle { solid dashed }
    path { hvcurve } from { A } to { B }
}
}

@LII {
In the following links, the @Code bias option determines how far
the link extends to the left of the leftmost node, or to the
right of the rightmost node.
}

@LI {
@Code {
"@Link"
"    path { lvrline }"
"    bias { 2.0f }"
}
||6ct
@Diag {
//0.5f
A:: @Circle /0.8c |1.5c B:: @Circle 
//
@ShowTags @Link
    pathstyle { solid dashed }
    path { lvrline } from { A } to { B }
}
&2.5c
@Diag {
//0.5f
|1.5c B:: @Circle /0.8c A:: @Circle 
//
@ShowTags @Link
    pathstyle { solid dashed }
    path { lvrline } from { A } to { B }
}
}

@LI {
@Code {
"@Link"
"    path { rvlline }"
"    bias { 2.0f }"
}
||6ct
@Diag {
//0.5f
A:: @Circle /0.8c |1.5c B:: @Circle 
//
@ShowTags @Link
    pathstyle { solid dashed }
    path { rvlline } from { A } to { B }
}
&2.5c
@Diag {
//0.5f
|1.5c B:: @Circle /0.8c A:: @Circle 
//
@ShowTags @Link
    pathstyle { solid dashed }
    path { rvlline } from { A } to { B }
}
}

@LI {
@Code {
"@Link"
"    path { lvrcurve }"
"    bias { 2.0f }"
"    radius { 1.0f }"
}
||6ct
@Diag {
//0.5f
A:: @Circle /0.8c |1.5c B:: @Circle 
//
@ShowTags @Link
    pathstyle { solid dashed }
    path { lvrcurve } from { A } to { B }
}
&2.5c
@Diag {
//0.5f
|1.5c B:: @Circle /0.8c A:: @Circle 
//
@ShowTags @Link
    pathstyle { solid dashed }
    path { lvrcurve } from { A } to { B }
}
}

@LI {
@Code {
"@Link"
"    path { rvlcurve }"
"    bias { 2.0f }"
"    radius { 1.0f }"
}
||6ct
@Diag {
//0.5f
A:: @Circle /0.8c |1.5c B:: @Circle 
//
@ShowTags @Link
    pathstyle { solid dashed }
    path { rvlcurve } from { A } to { B }
}
&2.5c
@Diag {
//0.5f
|1.5c B:: @Circle /0.8c A:: @Circle 
//
@ShowTags @Link
    pathstyle { solid dashed }
    path { rvlcurve } from { A } to { B }
}
}

@LI {
@Code {
"@Link"
"    path { dhuline }"
"    bias { 2.0f }"
}
||6ct
@Diag {
//0.5f
A:: @Circle /0.8c |1.5c B:: @Circle /2f
//
@ShowTags @Link
    pathstyle { solid dashed }
    path { dhuline } from { A } to { B }
}
&2.5c
@Diag {
//0.5f
|1.5c B:: @Circle /0.8c A:: @Circle /2f
//
@ShowTags @Link
    pathstyle { solid dashed }
    path { dhuline } from { A } to { B }
}
}

@LI {
@Code {
"@Link"
"    path { uhdline }"
"    bias { 2.0f }"
}
||6ct
@Diag {
//2.5f
A:: @Circle /0.8c |1.5c B:: @Circle
//
@ShowTags @Link
    pathstyle { solid dashed }
    path { uhdline } from { A } to { B }
}
&2.5c
@Diag {
//2.5f
|1.5c B:: @Circle /0.8c A:: @Circle
//
@ShowTags @Link
    pathstyle { solid dashed }
    path { uhdline } from { A } to { B }
}
}

@LI {
@Code {
"@Link"
"    path { dhucurve }"
"    bias { 2.0f }"
"    radius { 1.0f }"
}
||6ct
@Diag {
//0.5f
A:: @Circle /0.8c |1.5c B:: @Circle /2f
//
@ShowTags @Link
    pathstyle { solid dashed }
    path { dhucurve } from { A } to { B }
}
&2.5c
@Diag {
//0.5f
|1.5c B:: @Circle /0.8c A:: @Circle  /2f
//
@ShowTags @Link
    pathstyle { solid dashed }
    path { dhucurve } from { A } to { B }
}
}

@LI {
@Code {
"@Link"
"    path { uhdcurve }"
"    bias { 2.0f }"
"    radius { 1.0f }"
}
||6ct
@Diag {
//2.5f
A:: @Circle /0.8c |1.5c B:: @Circle
//
@ShowTags @Link
    pathstyle { solid dashed }
    path { uhdcurve } from { A } to { B }
}
&2.5c
@Diag {
//2.5f
|1.5c B:: @Circle /0.8c A:: @Circle
//
@ShowTags @Link
    pathstyle { solid dashed }
    path { uhdcurve } from { A } to { B }
}
}

@LII {
In the following links, the @Code "hfrac" and @Code "hbias" options
determine how far across from @Code "FROM" to @Code "TO" the path turns
vertical:  a fraction @Code "hfrac" of the way across, plus a distance
{@Code "hbias"}.  The default settings shown make this point halfway; by
changing @Code "hfrac" to 0 and giving a length to {@Code "hbias"}, one can
select a particular distance, rather than a fraction of the total distance.
}

@LI {
@Code {
"@Link"
"    path { hvhline }"
"    hfrac { 0.5 }"
"    hbias { 0f }"
"    radius { 1.0f }"
}
||6ct
@Diag {
//0.5f
A:: @Circle /0.8c |1.5c B:: @Circle 
//
@ShowTags @Link
    pathstyle { solid dashed }
    path { hvhline } from { A } to { B }
}
&2.5c
@Diag {
//0.5f
|1.5c B:: @Circle /0.8c A:: @Circle 
//
@ShowTags @Link
    pathstyle { solid dashed }
    path { hvhline } from { A } to { B }
}
}

@LI {
@Code {
"@Link"
"    path { hvhcurve }"
"    hfrac { 0.5 }"
"    hbias { 0f }"
"    radius { 1.0f }"
}
||6ct
@Diag {
//0.5f
A:: @Circle /0.8c |1.5c B:: @Circle 
//
@ShowTags @Link
    pathstyle { solid dashed }
    path { hvhcurve } from { A } to { B }
}
&2.5c
@Diag {
//0.5f
|1.5c B:: @Circle /0.8c A:: @Circle 
//
@ShowTags @Link
    pathstyle { solid dashed }
    path { hvhcurve } from { A } to { B }
}
}

@LI {
@Code {
"@Link"
"    path { vhvline }"
"    hfrac { 0.5 }"
"    hbias { 0f }"
"    radius { 1.0f }"
}
||6ct
@Diag {
//0.5f
A:: @Circle /1.8c |1.5c B:: @Circle 
//
@ShowTags @Link
    pathstyle { solid dashed }
    path { vhvline } from { A } to { B }
}
&2.5c
@Diag {
//0.5f
|1.5c B:: @Circle /1.8c A:: @Circle 
//
@ShowTags @Link
    pathstyle { solid dashed }
    path { vhvline } from { A } to { B }
}
}

@LI {
@Code {
"@Link"
"    path { vhvcurve }"
"    hfrac { 0.5 }"
"    hbias { 0f }"
"    radius { 1.0f }"
}
||6ct
@Diag {
//0.5f
A:: @Circle /1.8c |1.5c B:: @Circle 
//
@ShowTags @Link
    pathstyle { solid dashed }
    path { vhvcurve } from { A } to { B }
}
&2.5c
@Diag {
//0.5f
|1.5c B:: @Circle /1.8c A:: @Circle 
//
@ShowTags @Link
    pathstyle { solid dashed }
    path { vhvcurve } from { A } to { B }
}
}

@LII {
In the following links, the @Code "fbias" option determines
how far the curve extends away from the FROM node; the
@Code "tbias" option determines how far it extends away from
the TO node; and the @Code "bias" option determines how far
it extends above the higher or below the lower node.
}

@LI {
@Code {
"@Link"
"    path { dwrapline }"
"    tbias { 2.0f }"
"    bias { 2.0f }"
"    fbias { 2.0f }"
}
||6ct
@Diag {
//0.5f
A:: @Circle /0.8c |1.5c B:: @Circle /2f
//
@ShowTags @Link
    pathstyle { solid dashed }
    path { dwrapline } from { A } to { B }
}
&2.5c
@Diag {
//0.5f
|1.5c B:: @Circle /0.8c A:: @Circle /2f
//
@ShowTags @Link
    pathstyle { solid dashed }
    path { dwrapline } from { A } to { B }
}
}

@LI {
@Code {
"@Link"
"    path { uwrapline }"
"    tbias { 2.0f }"
"    bias { 2.0f }"
"    fbias { 2.0f }"
}
||6ct
@Diag {
//0.5f
/2f A:: @Circle /0.8c |1.5c B:: @Circle 
//
@ShowTags @Link
    pathstyle { solid dashed }
    path { uwrapline } from { A } to { B }
}
&2.5c
@Diag {
//0.5f
/2f |1.5c B:: @Circle /0.8c A:: @Circle 
//
@ShowTags @Link
    pathstyle { solid dashed }
    path { uwrapline } from { A } to { B }
}
}

@LI {
@Code {
"@Link"
"    path { dwrapcurve }"
"    tbias { 2.0f }"
"    bias { 2.0f }"
"    fbias { 2.0f }"
"    radius { 1.0f }"
}
||6ct
@Diag {
//0.5f
A:: @Circle /0.8c |1.5c B:: @Circle /2f
//
@ShowTags @Link
    pathstyle { solid dashed }
    path { dwrapcurve } from { A } to { B }
}
&2.5c
@Diag {
//0.5f
|1.5c B:: @Circle /0.8c A:: @Circle /2f
//
@ShowTags @Link
    pathstyle { solid dashed }
    path { dwrapcurve } from { A } to { B }
}
}

@LI {
@Code {
"@Link"
"    path { uwrapcurve }"
"    tbias { 2.0f }"
"    bias { 2.0f }"
"    fbias { 2.0f }"
"    radius { 1.0f }"
}
||6ct
@Diag {
//0.5f
/2f A:: @Circle /0.8c |1.5c B:: @Circle 
//
@ShowTags @Link
    pathstyle { solid dashed }
    path { uwrapcurve } from { A } to { B }
}
&2.5c
@Diag {
//0.5f
/2f |1.5c B:: @Circle /0.8c A:: @Circle 
//
@ShowTags @Link
    pathstyle { solid dashed }
    path { uwrapcurve } from { A } to { B }
}
}

@EndList
Here is the list of abbreviations for the standard paths (note
that @Code curve and @Code acurve are the same).  Each
path also has an abbreviation which adds a forward arrow:
@DP
@Tab
    @Fmta { @Col { @DisplayIndent @Wide & @Code { path "{" A "}" } } !
	    @Col @Code "@"B ! @Col @Code "@"C }
{
@FirstRowa
    A { line }
    B { Line }
    C { Arrow }
@Rowa
    A { doubleline }
    B { DoubleLine }
    C { DoubleArrow }
@Rowa
    A { curve }
    B { Curve }
    C { CurveArrow }
@Rowa
    A { acurve }
    B { ACurve }
    C { ACurveArrow }
@Rowa
    A { ccurve }
    B { CCurve }
    C { CCurveArrow }

@Rowa
    A { bezier }
    B { Bezier }
    C { BezierArrow }

@Rowa
    A { hvline }
    B { HVLine }
    C { HVArrow }
@Rowa
    A { vhline }
    B { VHLine }
    C { VHArrow }
@Rowa
    A { hvcurve }
    B { HVCurve }
    C { HVCurveArrow }
@Rowa
    A { vhcurve }
    B { VHCurve }
    C { VHCurveArrow }

@Rowa
    A { lvrline }
    B { LVRLine }
    C { LVRArrow }
@Rowa
    A { rvlline }
    B { RVLLine }
    C { RVLArrow }
@Rowa
    A { lvrcurve }
    B { LVRCurve }
    C { LVRCurveArrow }
@Rowa
    A { rvlcurve }
    B { RVLCurve }
    C { RVLCurveArrow }

@Rowa
    A { dhuline }
    B { DHULine }
    C { DHUArrow }
@Rowa
    A { uhdline }
    B { UHDLine }
    C { UHDArrow }
@Rowa
    A { dhucurve }
    B { DHUCurve }
    C { DHUCurveArrow }
@Rowa
    A { uhdcurve }
    B { RVLCurve }
    C { RVLCurveArrow }

@Rowa
    A { hvhline }
    B { HVHLine }
    C { HVHArrow }
@Rowa
    A { vhvline }
    B { VHVLine }
    C { VHVArrow }
@Rowa
    A { hvhcurve }
    B { HVHCurve }
    C { HVHCurveArrow }
@Rowa
    A { vhvcurve }
    B { VHVCurve }
    C { VHVCurveArrow }

@Rowa
    A { dwrapline }
    B { DWrapLine }
    C { DWrapArrow }
@Rowa
    A { uwrapline }
    B { UWrapLine }
    C { UWrapArrow }
@Rowa
    A { dwrapcurve }
    B { DWrapCurve }
    C { DWrapCurveArrow }
@Rowa
    A { uwrapcurve }
    B { UWrapCurve }
    C { UWrapCurveArrow }
}
@DP
Here is the complete list of options to the @Code "@Link" symbol.  The
options related to {@Code xlabel}, {@Code ylabel}, and {@Code zlabel}
have been omitted where they are the same as the {@Code linklabel} options.
@DP
1fx @Break @Tab
  hmargin { 1s }
  # vmargin { 0.6vx }
  @Fmth { @Col @Code A ! @Col @Code " " ! @Col @Code B ! @Col @Code " " !
	  @Col 0.3c @Wide ! @Col C }
  @Fmta { @Col @Code A ! @Col @Code "{" ! @Col @Code B ! @Col @Code "}" !
	  @Col 0.3c @Wide ! @Col C }
{
@Rowh
  A { "@Link" }
@Rowa
  A { "   path" }
  B { line }
  C { {@Code "line"}, {@Code "doubleline"}, {@Code "curve"}, {@Code "acurve"},
{@Code "ccurve"}, {@Code "bezier"},
{@Code "vhline"}, {@Code "hvline"}, {@Code "vhcurve"}, {@Code "hvcurve"},
{@Code "lvrline"}, {@Code "rvlline"}, {@Code "lvrcurve"}, {@Code "rvlcurve"},
{@Code "dhuline"}, {@Code "uhdline"}, {@Code "dhucurve"}, {@Code "uhdcurve"},
{@Code "hvhline"}, {@Code "vhvline"}, {@Code "hvhcurve"}, {@Code "vhvcurve"},
{@Code "dwrapline"}, {@Code "uwrapline"}, {@Code "dwrapcurve"},
{@Code "uwrapcurve"}, or any path }
@Rowa
  A { "   from"}
  B { 0,0 }
  C { any @I point or node label }
@Rowa
  A { "   to"}
  B { 1,1 }
  C { any @I point or node label }
@Rowa
  A { "   bias"}
  B { 2.0f }
  C { any @I length }
@Rowa
  A { "   fbias"}
  B { 2.0f }
  C { any @I length }
@Rowa
  A { "   tbias"}
  B { 2.0f }
  C { any @I length }
@Rowa
  A { "   hfrac"}
  B { 0.5 }
  C { any fractional @I number }
@Rowa
  A { "   hbias"}
  B { 0.0f }
  C { any @I length }
@Rowa
  A { "   radius"}
  B { 1.0f }
  C { any @I length }
@Rowa
  A { "   xindent"}
  B { 0.8f }
  C { any @I length }
@Rowa
  A { "   zindent"}
  B { 0.8f }
  C { any @I length }
@Rowa
  A { "   frompt"}
  B { 0 0 }
  C { any @I point }
@Rowa
  A { "   topt"}
  B { 0 0 }
  C { any @I point }
@Rowa
  A { "   pathstyle" }
  B { solid }
  C { {@Code solid}, {@Code dashed}, {@Code cdashed}, {@Code dotted},
{@Code dotdashed}, {@Code dotcdashed}, {@Code dotdotdashed},
{@Code dotdotcdashed}, {@Code dotdotdotdashed}, {@Code dotdotdotcdashed},
{@Code noline}, or any sequence of one or more of these values }
@Rowa
  A { "   pathdashlength"}
  B { 0.2f }
  C { any @I length }
@Rowa
  A { "   pathwidth" }
  B { thin }
  C { {@Code thin}, {@Code medium}, {@Code thick}, or any @I length }
@Rowa
  A { "   pathcolour" }
  B { nochange }
  C { @Code nochange or any colour from  Section {@NumberOf colour} }
@Rowa
  A { "   pathgap" }
  B { thin }
  C { {@Code thin}, {@Code medium}, {@Code thick}, or any @I length }
@Rowa
  A { "   arrow"}
  B { no }
  C { {@Code no}, {@Code yes}, {@Code forward}, {@Code back},
or {@Code both} }
@Rowa
  A { "   arrowstyle"}
  B { solid }
  C { {@Code solid}, {@Code solidwithbar}, {@Code halfopen}, {@Code open},
{@Code curvedsolid}, {@Code curvedhalfopen}, {@Code curvedopen},
{@Code circle}, {@Code box}, or {@Code many} }
@Rowa
  A { "   arrowwidth"}
  B { 0.3f }
  C { any @I length }
@Rowa
  A { "   arrowlength"}
  B { 0.5f }
  C { any @I length }
@Rowa
  A { "   backarrowstyle"}
  B { solid }
  C { {@Code solid}, {@Code solidwithbar}, {@Code halfopen}, {@Code open},
{@Code curvedsolid}, {@Code curvedhalfopen}, {@Code curvedopen},
{@Code circle}, {@Code box}, or {@Code many} }
@Rowa
  A { "   backarrowwidth"}
  B { 0.3f }
  C { any @I length }
@Rowa
  A { "   backarrowlength"}
  B { 0.5f }
  C { any @I length }
@Rowa
  A { "   linklabel"}
  B {  }
  C { any object }
@Rowa
  A { "   linklabelmargin"}
  B { 0.2f }
  C { any length from Section {@NumberOf objects} }
@Rowa
  A { "   linklabelfont"}
  B { -2p }
  C { any value suitable for the @Code "@Font" symbol }
@Rowa
  A { "   linklabelbreak"}
  B { ragged nohyphen }
  C { any value suitable for the @Code "@Break" symbol }
@Rowa
  A { "   linklabelformat"}
  B { "@Body" }
  C { any object, usually containing @Code "@Body" }
@Rowa
  A { "   linklabelpos"}
  B { }
  C { any @I point }
@Rowa
  A { "   linklabelangle"}
  B { horizontal }
  C { {@Code horizontal}, {@Code aligned}, or {@Code perpendicular};
{@Code parallel}, {@Code antiparallel}, or any @I angle }
@Rowa
  A { "   linklabelprox"}
  B { above }
  C { {@Code above}, {@Code below}, {@Code left}, {@Code right},
{@Code inside}, or {@Code outside}; {@Code CTR}, {@Code N}, {@Code S},
{@Code E}, {@Code W}, {@Code NE}, {@Code NW}, {@Code SW}, {@Code SE},
{@Code NNW}, {@Code NNE}, {@Code SSW}, or {@Code SSE}
}
@Rowa
  A { "   linklabelctr"}
  B { no }
  C { @Code yes or @Code no }
@Rowa
  A { "   linklabeladjust"}
  B { 0 0 }
  C { any @I point }
@Rowa
  A { "   xlabelpos"}
  B { LFROM }
  C { any @I point }
@Rowa
  A { "   ylabelpos"}
  B { LMID }
  C { any @I point }
@Rowa
  A { "   ylabelctr"}
  B { yes }
  C { @Code yes or @Code no }
@Rowa
  A { "   zlabelpos"}
  B { LTO }
  C { any @I point }
@Rowa
  A { "   fromlabel"}
  B {  }
  C { any object }
@Rowa
  A { "   fromlabelmargin"}
  B { 0f }
  C { any length from Section {@NumberOf objects} }
@Rowa
  A { "   fromlabelfont"}
  B { "-2p" }
  C { Any value suitable for the @Code "@Font" symbol }
@Rowa
  A { "   fromlabelbreak"}
  B { ragged nohyphen }
  C { Any value suitable for the @Code "@Break" symbol }
@Rowa
  A { "   fromlabelformat"}
  B { "@Body" }
  C { any object, usually containing @Code "@Body" }
@Rowa
  A { "   fromlabelpos"}
  B { FROM }
  C { any @I point }
@Rowa
  A { "   fromlabelangle"}
  B { antiparallel }
  C { {@Code horizontal}, {@Code aligned}, or {@Code perpendicular};
{@Code parallel}, {@Code antiparallel}, or any @I angle }
@Rowa
  A { "   fromlabelprox"}
  B { W }
  C { {@Code above}, {@Code below}, {@Code left}, {@Code right},
{@Code inside}, or {@Code outside}; {@Code CTR}, {@Code N}, {@Code S},
{@Code E}, {@Code W}, {@Code NE}, {@Code NW}, {@Code SW}, {@Code SE},
{@Code NNW}, {@Code NNE}, {@Code SSW}, or {@Code SSE}
}
@Rowa
  A { "   fromlabelctr"}
  B { no }
  C { @Code yes or @Code no }
@Rowa
  A { "   fromlabeladjust"}
  B { 0 0 }
  C { any @I point }
@Rowa
  A { "   tolabel"}
  B {  }
  C { any object }
@Rowa
  A { "   tolabelmargin"}
  B { 0f }
  C { any length from Section {@NumberOf objects} }
@Rowa
  A { "   tolabelfont"}
  B { "-2p" }
  C { Any value suitable for the @Code "@Font" symbol }
@Rowa
  A { "   tolabelbreak"}
  B { ragged nohyphen }
  C { Any value suitable for the @Code "@Break" symbol }
@Rowa
  A { "   tolabelformat"}
  B { "@Body" }
  C { any object, usually containing @Code "@Body" }
@Rowa
  A { "   tolabelpos"}
  B { TO }
  C { any @I point }
@Rowa
  A { "   tolabelangle"}
  B { parallel }
  C { {@Code horizontal}, {@Code aligned}, or {@Code perpendicular};
{@Code parallel}, {@Code antiparallel}, or any @I angle }
@Rowa
  A { "   tolabelprox"}
  B { W }
  C { {@Code above}, {@Code below}, {@Code left}, {@Code right},
{@Code inside}, or {@Code outside}; {@Code CTR}, {@Code N}, {@Code S},
{@Code E}, {@Code W}, {@Code NE}, {@Code NW}, {@Code SW}, {@Code SE},
{@Code NNW}, {@Code NNE}, {@Code SSW}, or {@Code SSE}
}
@Rowa
  A { "   tolabelctr"}
  B { no }
  C { @Code yes or @Code no }
@Rowa
  A { "   tolabeladjust"}
  B { 0 0 }
  C { any @I point }
}
@DP
Here is the complete list of options to the @Code "@Tree" symbol:
@DP @OneRow 1fx @Break @Tab
  hmargin { 1s }
  # vmargin { 0.6vx }
  @Fmth { @Col @Code A ! @Col @Code " " ! @Col @Code B ! @Col @Code " " !
	  @Col 1.0c @Wide ! @Col C }
  @Fmta { @Col @Code A ! @Col @Code "{" ! @Col @Code B ! @Col @Code "}" !
	  @Col 1.0c @Wide ! @Col C }
{
@Rowh
  A { "@Tree" }
@Rowa
  A { "   treehindent" }
  B { ctr }
  C { {@Code left}, {@Code ctr}, {@Code right}, or any length from
Section {@NumberOf objects} }
}
@DP
The @Code "@HTree" option has a similar @Code "treevindent" option,
which may be {@Code "top"}, {@Code ctr}, {@Code foot}, or any length
from Section {@NumberOf objects}.
@PP
Here are all the syntax diagrams symbols, used within {@Code "@SyntaxDiag"}
usually but also available within {@Code "@Diag"}.  To begin with we have
the six starter symbols:
@CD @SyntaxDiag {
@Tbl
    aformat { @Cell @Code A | @Cell B | @Cell | @Cell @Code C |
	      @Cell D | @Cell | @Cell @Code E | @Cell F }
{
@Rowa
    A { "@StartRight ..." }
    B { @StartRight @ACell "..." }
    C { "@StartUp ..." }
    D { @StartUp @ACell "..." }
    E {
"@StartRightRight"
      "A { ... }"
      "B { ... }"
}
    F { @StartRightRight A { @ACell A } B { @ACell B } }
@Rowa
    A { "@StartLeft ..." }
    B { @StartLeft @ACell "..." }
    C { "@StartDown ..." }
    D { @StartDown @ACell "..." }
    E {
"@StartRightDown"
      "A { ... }"
      "B { ... }"
}
    F { @StartRightDown A { @ACell A } B { @ACell B } }
}
}
And here are all the syntax diagram types, shown in all four directions
(right, up, left, and down).  @Code "@Sequence" and @Code "@Select" may
have up to twelve options, {@Code "A"} to {@Code "L"}.
@IndentedList

@LI @SyntaxDiag { @Four code { "@ACell ..." } @ACell "..." }

@LI @SyntaxDiag { @Four code { "@BCell ..." } @BCell "..." }

@LI @SyntaxDiag { @Four code { "@CCell ..." } @CCell "..." }

@LI @SyntaxDiag { @Four code { "@Skip"      } @Skip        }

@LI @SyntaxDiag { @Four code {
"@Sequence"
      "A { ... }"
      "B { ... }"
      "C { ... }"
} @Sequence A { @ACell A } B { @ACell B } C { @ACell C } }

@LI @SyntaxDiag { @Four code {
"@Select"
      "A { ... }"
      "B { ... }"
      "C { ... }"
} @Select A { @ACell A } B { @ACell B } C { @ACell C } }

@LI @SyntaxDiag { @Four code { "@Optional ..." } @Optional @ACell "..." }

@LI @SyntaxDiag { @Four code { "@OptionalDiverted ..." }
	@OptionalDiverted @ACell "..." }

@LI @SyntaxDiag { @Four code { "@Diverted ..." } @Diverted @ACell "..." }

@LI @SyntaxDiag { @Four code {
"@OneOrBoth"
      "A { ... }"
      "B { ... }"
} @OneOrBoth A { @ACell A } B { @ACell B } }

@LI @SyntaxDiag { @Four code {
"@Loop"
      "A { ... }"
      "B { ... }"
} @Loop A { @ACell A } B { @ACell B } }

@LI @SyntaxDiag { @Four code { "@Repeat ..." } @Repeat @ACell "..." }

@LI @SyntaxDiag { @Four code {
"@LoopOpposite"
      "A { ... }"
      "B { ... }"
} @LoopOpposite A { @ACell A } B { @ACell B } }

@LI @SyntaxDiag { @Four code { "@RepeatOpposite ..." }
	@RepeatOpposite @ACell "..." }

@LI @SyntaxDiag { @Four code { "@RepeatDiverted ..." }
	@RepeatDiverted @ACell "..." }

@EndList
The @Code "@Diag" symbol and to the {@Code "@DiagSetup"} setup
file symbol have all of the options of {@Code "@Node"}, {@Code "@Link"},
{@Code "@Tree"}, and {@Code "@HTree"}.  They also have the following
options:
@DP
1fx @Break @Tab
  hmargin { 1s }
  # vmargin { 0.6vx }
  @Fmth { @Col @Code A ! @Col @Code " " ! @Col @Code B ! @Col @Code " " !
	  @Col 1.0c @Wide ! @Col C }
  @Fmta { @Col @Code A ! @Col @Code "{" ! @Col @Code B ! @Col @Code "}" !
	  @Col 1.0c @Wide ! @Col C }
{
@Rowh
  A { "@Diag" }
@Rowa
  A { "   maxlabels" }
  B { 200 }
  C { any whole number }
@Rowa
  A { "   save" }
  B { no }
  C { @Code no or @Code yes }
@Rowa
  A { "   treehsep" }
  B { 0.5f }
  C { any length from Section {@NumberOf objects} }
@Rowa
  A { "   syntaxgap" }
  B { 0.35f }
  C { any length from Section {@NumberOf objects} }
@Rowa
  A { "   syntaxbias" }
  B { 1.0f }
  C { any length from Section {@NumberOf objects} }
@Rowa
  A { "   syntaxradius" }
  B { 0.3f }
  C { any length from Section {@NumberOf objects} }
}
@DP
The following lists define all the ways to specify numbers, lengths,
angles, points, and booleans.  Brief explanations appear to the right,
with the symbols' precedences in parentheses.
@DP
1fx @Break @Tab
  # vmargin { 0.6vx }
  @Fmth { @Col { &@DisplayIndent     A } ! @Col   }
  @Fmta { @Col { &@DisplayIndent &2s A } ! @Col B }
{

@Rowh A { @I number } vmargin { 0.2vx }
@Rowh
@Rowa
  A { {@Sym minus}27.56 }
  B { or any literal number }
@Rowa
  A { @Code sqrt @I number }
  B { square root (99) }
@Rowa
  A { @Code abs @I number }
  B { absolute value (99) }
@Rowa
  A { @Code ceiling @I number }
  B { least integer greater than or equal to (99) }
@Rowa
  A { @Code floor @I number }
  B { greatest integer less than or equal to (99) }
@Rowa
  A { @Code truncate @I number }
  B { delete fractional part (99) }
@Rowa
  A { @Code round @I number }
  B { round to nearest integer (99) }
@Rowa
  A { @Code sin @I angle }
  B { sine of angle measured in degrees (99) }
@Rowa
  A { @Code cos @I angle }
  B { cosine of angle measured in degrees (99) }
@Rowa
  A { @I number @Code atan @I number }
  B { arc tangent of first over second (98) }
@Rowa
  A { @I number @Code exp @I number }
  B { first number raised to second number (98) }
@Rowa
  A { @I number @Code log @I number }
  B { logarithm of second number to base first (98) }
@Rowa
  A { @I number @Code rand @I number }
  B { random real number in this range inclusive (98) }
@Rowa
  A { @I number @Code max @I number }
  B { the larger of two numbers (98) }
@Rowa
  A { @I number @Code min @I number }
  B { the smaller of two numbers (98) }
@Rowa
  A { @I number @Code "*" @I number }
  B { the product of two numbers (97) }
@Rowa
  A { @I number @Code "/" @I number }
  B { real-valued division (96, left associative) }
@Rowa
  A { @I length @Code "/" @I length }
  B { the ratio of two lengths (96, left associative) }
@Rowa
  A { @I angle @Code "/" @I angle }
  B { the ratio of two angles (96, left associative) }
@Rowa
  A { @I number @Code idiv @I number }
  B { integer division of two numbers (96, left associative) }
@Rowa
  A { @I number @Code mod @I number }
  B { integer remainder when first divided by second (96) }
@Rowa
  A { @I number @Code "+" @I number }
  B { sum of two numbers (96, left associative) }
@Rowa
  A { @Code "+" @I number }
  B { identity operation (96) }
@Rowa
  A { @I number @Sym minus @I number }
  B { difference of two numbers (96, left associative) }
@Rowa
  A { @Sym minus @I number }
  B { negation (96) }
@Rowa
  A { @Code sides }
  B { ({@Code outline} only) value of the node's @Code sides option }

@Rowh
@Rowh
@Rowh
@Rowh
@Rowh A { @I length } vmargin { 0.2vx }
@Rowh
@Rowa
  A { 0 }
  B { zero }
@Rowa
  A { @Code xsize }
  B { ({@Code outline} only) distance to right boundary }
@Rowa
  A { @Code ysize }
  B { ({@Code outline} only) distance to top boundary }
@Rowa
  A { @Code xmark }
  B { ({@Code outline} only) distance to column mark }
@Rowa
  A { @Code ymark }
  B { ({@Code outline} only) distance to row mark }
@Rowa
  A { @Code margin }
  B { ({@Code outline} only) value of the node's @Code margin option }
@Rowa
  A { @Code shadow }
  B { ({@Code outline} only) value of the node's @Code shadow option }
@Rowa
  A { @I number @Code i }
  B { @I number inches (100) }
@Rowa
  A { @I number @Code c }
  B { @I number centimetres (100) }
@Rowa
  A { @I number @Code p }
  B { @I number points (100) }
@Rowa
  A { @I number @Code m }
  B { @I number ems (100) }
@Rowa
  A { @I number @Code s }
  B { @Code 1s is the current width of a space (100) }
@Rowa
  A { @I number @Code v }
  B { @Code 1v is the current inter-line space (100) }
@Rowa
  A { @I number @Code f }
  B { @Code 1f is the size of the current font (100) }
@Rowa
  A { @Code "xcoord" @I point }
  B { the @I x coordinate of the point (99) }
@Rowa
  A { @Code "ycoord" @I point }
  B { the @I y coordinate of the point (99) }
@Rowa
  A { @Code abs @I length }
  B { absolute value (99) }
@Rowa
  A { @I length @Code rand @I length }
  B { random real length in this range inclusive (98) }
@Rowa
  A { @I length @Code max @I length }
  B { the larger of two lengths (98) }
@Rowa
  A { @I length @Code min @I length }
  B { the smaller of two lengths (98) }
@Rowa
  A { @I point @Code "distance" @I point }
  B { (non-negative) distance between two points (98) }
@Rowa
  A { @I length @Code "*" @I number }
  B { length multiplied by number (97) }
@Rowa
  A { @I number @Code "*" @I length }
  B { length multiplied by number (97) }
@Rowa
  A { @I length @Code "/" @I number }
  B { length divided by number (96, left associative) }
@Rowa
  A { @I length @Code "+" @I length }
  B { sum of two lengths (96, left associative) }
@Rowa
  A { @Code "+" @I length }
  B { identity operation (96) }
@Rowa
  A { @I length @Sym minus @I length }
  B { difference of two lengths (96, left associative) }
@Rowa
  A { @Sym minus @I length }
  B { negation (96) }

@Rowh
@Rowh
@Rowh
@Rowh
@Rowh A { @I angle } vmargin { 0.2vx }
@Rowh
@Rowa
  A { @I number @Code d }
  B { @I number degrees (100) }
@Rowa
  A { @I number }
  B { @I number degrees (@Code d is optional) (100) }
@Rowa
  A { @Code parallel }
  B { ({@Code labelangle} options only) angle parallel to curve at label point }
@Rowa
  A { @Code antiparallel }
  B { ({@Code labelangle} options only) angle antiparallel to curve at label point }
@Rowa
  A { @Code perpendicular }
  B { ({@Code labelangle} options only) angle perpendicular to curve at label point }
@Rowa
  A { @Code antiperpendicular }
  B { ({@Code labelangle} options only) angle antiperpendicular to curve at label point }
@Rowa
  A { {@I label}{@Code "??ANGLE"} }
  B { angle parallel to curve at {@I label} if known, else @Code "0d" (99) }
@Rowa
  A { @Code anglefix @I angle }
  B { @I angle normalized to between @Code 0d inclusive and @Code 360d exclusive (99) }
@Rowa
  A { @Code abs @I angle }
  B { absolute value (99) }
@Rowa
  A { @I length @Code atan @I length }
  B { arc tangent of first over second (98) }
@Rowa
  A { @I point @Code "angleto" @I point }
  B { angle from first point to second (98) }
@Rowa
  A { @I angle @Code rand @I angle }
  B { random angle in this range inclusive (98) }
@Rowa
  A { @I angle @Code max @I angle }
  B { the larger of two angles (98) }
@Rowa
  A { @I angle @Code min @I angle }
  B { the smaller of two angles (98) }
@Rowa
  A { @I angle @Code "*" @I number }
  B { angle multiplied by number (97) }
@Rowa
  A { @I number @Code "*" @I angle }
  B { angle multiplied by number (97) }
@Rowa
  A { @I angle @Code "/" @I number }
  B { division of angle by number (96, left associative) }
@Rowa
  A { @I angle @Code "+" @I angle }
  B { sum of two angles (96, left associative) }
@Rowa
  A { @Code "+" @I angle }
  B { identity operation (96) }
@Rowa
  A { @I angle @Sym minus @I angle }
  B { difference of two angles (96, left associative) }
@Rowa
  A { @Sym minus @I angle }
  B { negation (96) }
@Rowa
  A { @Code angle }
  B { ({@Code outline} only) value of the node's @Code angle option }


@Rowh
@Rowh
@Rowh
@Rowh
@Rowh A { @I point } vmargin { 0.2vx }
@Rowh
@Rowa
  A { @I label }
  B { a previously defined label }
@Rowa
  A { {@I any}{@Code "??"}{@I label} }
  B { {@I any}{@Code "@"}{@I label} if sensible, else {@I any} (99) }
@Rowa
  A { @Code "prev" }
  B { the previous point in a shape }
@Rowa
  A { @I length  @Code "atangle"  @I angle }
  B { point at distance and angle from origin (89) }
@Rowa
  A { @I "point/tag" @Code "boundaryatangle" @I angle }
  B { @I {point}, or point on boundary of @I tag at @I angle (89) }
@Rowa
  A { @I point  @Code "**"  @I number }
  B { multiplication of point by number (88) }
@Rowa
  A { @I point  @Code "++"  @I point }
  B { vector sum of two points (87) }
@Rowa
  A { @I point  {@Sym minus}{@Sym minus}  @I point }
  B { vector difference of two points (87) }
@Rowa
  A { @I {number, number} }
  B { @I x and @I y coordinates with respect to base (70) }
@Rowa
  A { @I {length  length} }
  B { @I x and @I y distance from origin (5) }
@Rowa
  A { @Code from }
  B { ({@Code path} only) the value of the link's @Code from option }
@Rowa
  A { @Code to }
  B { ({@Code path} only) the value of the link's @Code to option }

@Rowh
@Rowh
@Rowh
@Rowh
@Rowh A { @I boolean } vmargin { 0.2vx }
@Rowh
@Rowa
  A { @I number @Code "=" @I number }
  B { @M { non = }; also between lengths (79) }
@Rowa
  A { @I number @Code "!=" @I number }
  B { @M { non != }; also between lengths (79) }
@Rowa
  A { @I number @Code "==" @I number }
  B { @M { non = } between angles (79) }
@Rowa
  A { @I number @Code "!==" @I number }
  B { @M { non != } between angles (79) }
@Rowa
  A { @I number @Code "<=" @I number }
  B { @M { non <= }; also between lengths (79) }
@Rowa
  A { @I number @Code "<" @I number }
  B { @M { non < }; also between lengths (79) }
@Rowa
  A { @I number @Code ">=" @I number }
  B { @M { non >= }; also between lengths (79) }
@Rowa
  A { @I number @Code ">" @I number }
  B { @M { non > }; also between lengths (79) }
@Rowa
  A { @Code "not" @I boolean }
  B { Logical not (78) }
@Rowa
  A { @I boolean @Code "and" @I boolean }
  B { Logical and (77) }
@Rowa
  A { @I boolean @Code "or" @I boolean }
  B { Logical or (76) }
@Rowa
  A { @I boolean @Code "xor" @I boolean }
  B { Logical exclusive or (76) }

}
@DP
A length is represented in PostScript by a single number on the operand
stack; so is an angle.  Therefore all number operations can be applied
to lengths and angles as well, but the results will not always be
useful.  For example, rounding a length to the nearest integer is
not a useful thing to do because the result depends on the basic unit
(what does 1 equal as a length?) which is implementation-dependent and
genuinely subject to change.  Rounding the @I ratio of two lengths does
make sense.  The above is an attempt to list only the useful operations;
but if you really need the logarithm of an angle, you can have it.
@PP
Angles are a little more amenable to this kind of thing because they are
always measured in degrees.  However, angles suffer from the problem that
{@Code 0d} is really the same angle as {@Code 360d}.  For this reason,
separate equality and inequality operators for angles are provided which
ignore multiples of {@Code 360d}, and less than and similar relations
are not defined for angles, because they inherently are not well
defined.  See also the @Code anglefix symbol above.
@PP
A point is represented by two lengths (which are numbers) on the
stack.  Those familiar with PostScript and willing to sacrifice portability
and increase their risk of error can therefore write, for example,
@OneCol { @I point @Code "exch" } to obtain the reflection of a point about
the main diagonal, and so on.
@PP
The following may have a result of any type, depending on
their options.  The options and result may be a
sequence of things as required in shapes, including @Code "[]" and
so forth.
@IndentedList
@LI @OneRow lines @Break {
@Code if
    @Code "cond {" @I boolean @Code "}"
    @Code "then {" @I anything @Code "}"
    @Code "else {" @I anything @Code "}"
}
@LI @OneRow lines @Break {
@I angle @Code quadcase
    @Code "0 {" @I anything @Code "}"
    @Code "0-90 {" @I anything @Code "}"
    @Code "90 {" @I anything @Code "}"
    @Code "90-180 {" @I anything @Code "}"
    @Code "180 {" @I anything @Code "}"
    @Code "180-270 {" @I anything @Code "}"
    @Code "270 {" @I anything @Code "}"
    @Code "270-360 {" @I anything @Code "}"
}
@LI @OneRow lines @Break {
@I number @Code signcase
    @Code "neg {" @I anything @Code "}"
    @Code "zero {" @I anything @Code "}"
    @Code "pos {" @I anything @Code "}"
}
@LI @OneRow lines @Break {
@Code "xloop from {" @I number "} to {" @I number "} by {" @I number "} do {"
    @I anything
@Code "}"
}
@LI @OneRow lines @Break {
@Code "yloop from {" @I number "} to {" @I number "} by {" @I number "} do {"
    @I anything
@Code "}"
}
@LI @OneRow lines @Break {
@Code "zloop from {" @I number "} to {" @I number "} by {" @I number "} do {"
    @I anything
@Code "}"
}
@EndList
The @Code "if" symbol returns @Code "then" or @Code "else" depending on
the value of {@Code "cond"}, and @Code "signcase" returns {@Code "neg"},
{@Code zero}, or {@Code pos} depending on whether @I number (which
may also be an angle or a length) is negative, zero, or positive.  The
@Code "quadcase" symbol decides whether the given angle points in
one of the four horizontal or vertical directions, or into the quadrants
between them, and returns the appropriate option.  Don't be misled by
the unorthodox option names; it is not possible to give your own
ranges, only these ones.
@PP
The loops return a sequence of
repetitions of {@I anything}; any occurrences of {@Code x} in
{@Code xloop} will be replaced by the current value of the loop counter,
and similarly for the other loops.
@PP
Symbols not covered in this summary are the retagging symbol @Code "::"
(Section {@NumberOf dia_tags}); the symbols available within the
{@Code "@Tree"} symbol (Section {@NumberOf dia_posi}); and {@Code ":<"},
{@Code ":="}, {@Code "@ShowPoints"}, {@Code "@ShowTags"}, and
{@Code "@ShowDirections"} from Section {@NumberOf dia_defi}.
@End @Section
