I created the following diagram using Forest version 1:
\documentclass[tikz,border=10pt]{standalone}
\usepackage{forest-1}% forest v.1
\begin{document}
\begin{forest}
for tree={
font=\sffamily\scriptsize,
line width=1pt,
draw,
anchor=west,
child anchor=west,
parent anchor=east,
grow'=east,
align=center,
edge path={
\noexpand\path[line width=1pt, ->, \forestoption{edge}]
(!u.parent anchor) -| +(5pt,0) -- +(5pt,0) |- (.child anchor) \forestoption{edge label};
},
for={Lu}{if={n_children==1}{l sep+=10pt}{}},
},
where level={1}{s+=-20pt}{},
[Here\\Village, name=pc
[There village\\your bird, name=arid
]
[, phantom
[Bananas, name=fb, xshift=-15pt, where n children=0{tier=sk}{}
[Pineapple, name=sf
[Middling\\villages?, name=solar
[Current\\paper, name=cp, edge label={node [font=\sffamily\scriptsize, near end, auto, xshift=-1.5pt] {Imprudent}}
]
]
[Creative\\endearments?, name=apple
[Fantastic\\imaginations, name=su, edge label={node [font=\sffamily\scriptsize, near end, auto, xshift=-1.5pt] {Basic}}
]
]
[Heathen\\hopscotch?, name=pear
[Beneficent\\benevolence, name=cl, edge label={node [font=\sffamily\scriptsize, near end, xshift=-1.5pt, below] {Higher}}, edge={draw=none}
]
]
]
[Zoological, name=gf
[Orange\\kangaroos?, name=star
[Strawberry\\seeker, name=rs, edge label={node [font=\sffamily\scriptsize, near end, xshift=-1.5pt, below] {Lower}}
]
]
[Fragility of\\foundations?, name=hercules
[Memorial\\cooks, name=ws, edge label={node [font=\sffamily\scriptsize, near end, xshift=-1.5pt, below] {Earthling}}
]
]
[Best\\antelopes?, name=astro
[Stellar\\horizons, name=ca, edge label={node [font=\sffamily\scriptsize, near end, xshift=-1.5pt, below] {Martian}}
]
]
]
]
]
[Bad hollows\\spotty slugs, name=avid
]
]
\begin{scope}[line width=1pt, ->]
\draw (solar.east) -- (solar.east -| apple.east) -| +(5pt,0) -- +(5pt,0) |- (su.west);
\draw (apple.east) -| +(5pt,0) -- +(5pt,0) |- (cp.west);
\draw (pear.east) -- (pear.east -| apple.east) -| +(5pt,0) -- +(5pt,0) |- (cp.west);
\draw (pear.east) -- (pear.east -| apple.east) -| +(5pt,0) -- +(5pt,0) |- (su.west);
\draw (star.east) -- (star.east -| apple.east) -| +(5pt,0) -- +(5pt,0) |- (cl.west);
\draw (star.east) -- (star.east -| apple.east) -| +(5pt,0) -- +(5pt,0) |- (ws.west);
\draw (star.east) -- (star.east -| apple.east) -| +(5pt,0) -- +(5pt,0) |- (ca.west);
\draw (astro.east) -- (astro.east -| apple.east) -| +(5pt,0) -- +(5pt,0) |- (cl.west);
\draw (astro.east) -- (astro.east -| apple.east) -| +(5pt,0) -- +(5pt,0) |- (rs.west);
\draw (astro.east) -- (astro.east -| apple.east) -| +(5pt,0) -- +(5pt,0) |- (ws.west);
\draw (hercules.east) -- (hercules.east -| apple.east) -| +(5pt,0) -- +(5pt,0) |- (cl.west);
\draw (hercules.east) -- (hercules.east -| apple.east) -| +(5pt,0) -- +(5pt,0) |- (rs.west);
\draw (hercules.east) -- (hercules.east -| apple.east) -| +(5pt,0) -- +(5pt,0) |- (ca.west);
\draw (avid.north) -- (avid.north |- fb.south);
\draw (arid.south -| avid.north) -- (avid.north |- fb.north);
\end{scope}
\end{forest}
\end{document}
This code will not compile with v.2 or newer of Forest because
for={Lu}{if={n_children==1}{l sep+=10pt}{}},
is no longer valid code: for was removed by the upgrade.
The manual tells me that the key has been renamed to for group (p. 85):
These keys have been renamed:
old new compat key (all but the last are in -most) ... for for group 1.0-for ...
I ended up omitting this diagram from my slides altogether together today because I couldn't figure out how to update this for current Forest from the instructions in the manual.
Initially, I tried,
for group={Lu}{if={n_children==1}{l sep+=10pt}{}},
However, this did not go well:
! Package pgfkeys Error: I do not know the key '/tikz/{Lu}{if={n_children==1}{l
sep+=10pt}{}}' and I am going to ignore it. Perhaps you misspelled it.
See the pgfkeys package documentation for explanation.
I take it this means that Forest parses for group= but then tries to pass {Lu}{if ...} to TikZ as a single key. I'm not sure why. I'd expect it to look for something to group and so to get some sort of error from Forest, if nothing else.
Clicking on the link for information about for group, I end up on page 30 with information about for <step>. Since this includes examples such as
for nodewalk={uu2}{blue}
and
for n=2{circle,draw}
it is not obvious what I'm meant to do differently with for group.
The group step is documented on page 50-1.
step
group=<nodewalk>Treat
<nodewalk>as a single step of the (outer) nodewalk, i.e. the outer every-step keylist is executed only at the end of the embedded nodewalk. The embedded<nodewalk>inherits history from the outer nodewalk. Using this key is equivalent to writingNodewalk={every step=independent,history=inherited}<nodewalk>{}, current→ It is safe to modify the every-step keylist of
<nodewalk>.→ for group is also defined.
Now, I must admit that embedded node walks remain a bit of a mystery to me and my heart tends to sink when I find what I think I need in this part of the manual.
If group is defined in this way, however, I'm not sure how for group can make sense, since for Nodewalk doesn't seem to make sense. That is, it seems that group can only be a step in an inner, rather than an outer, nodewalk.
I therefore try
for nodewalk={group={Lu}}{if={n_children==1}{l sep+=10pt}{}},
This tries to use group as a step in an inner, embedded nodewalk. This will cause the last step to become the current step in the outer nodewalk, if I've understood correctly, and my conditional should then be applied in, I think, the same way as the original code in version 1.
However, I get another error
! Package forest Error: nodewalk stepped to the invalid node
(forest) nodewalk stack: ",root',tree,group,last leaf".
See the forest package documentation for explanation.
This is a Forest error, which is better, but I'm not sure I understand it. It looks as if the L is occurring in the outer nodewalk, after group. But Lu is supposed to be the group, so I'm not sure what this means.
However, this might simply be due to another change from version 1 to 2 of Forest: namely, that a non-existent step now causes an error in cases where it did not used to do so.
I try
for nodewalk={on invalid=fake,group={Lu}}{if={n_children==1}{l sep+=10pt}{}},
However, I can't use on invalid in an outer nodewalk in this way. I don't completely understand why, but I do know it doesn't work.
I therefore try
for nodewalk={%
Nodewalk={on invalid=fake}{group={Lu}}{if={n_children==1}{l sep+=10pt}{}}
}{},
which gives me
! Package forest Error: nodewalk stepped to the invalid node
(forest) nodewalk stack: ",root',tree,Nodewalk,group,last leaf".
Thinking that I may need the on invalid inside the group, I try
for nodewalk={%
Nodewalk={on invalid=fake}{group={on invalid=fake,Lu}}{if={n_children==1}{l sep+=10pt}{}}
}{},
which complains that f is not a valid choice for on invalid again.
Giving up, I change my call line to
\usepackage[compat=1.0-for]{forest}
and reinstate
for={Lu}{if={n_children==1}{l sep+=10pt}{}},
This gives me the complaint about invalidity again:
! Package forest Error: nodewalk stepped to the invalid node
(forest) nodewalk stack: ",root',tree,last leaf".
So I try
\usepackage[compat=1.0-for,compat=1.0-forstep]{forest}
which gives me an error I have no idea what to do with
! Undefined control sequence.
\forest@forstepwrapper ...dewalk@config@oninvalid
}}\forest@marshal
I give up and cut the diagram out of my presentation for class.
If I use
\usepackage[compat=1.0-all]{forest}
then my code does compile with version 2, but it looks nothing like the result obtained with version 1:
which is hardly what one might hope a compatibility key would do!
On the other hand, using compat=1.0-most still produces the invalidity error.
How should the upgrade instructions be applied in this case and how can that be determined from the list of changes or other revisions in the manual?
Why do the keys for compatibility fail here and why so spectacularly in the case of compat=1.0-all?
