Using the \newarrow command from Taylor's commutative diagrams package

Question

I want to define new arrows to use in a commutative diagram, but I just can't make it work. The documentation is not particularly helpful; it doesn't even tell you where to put the

\newarrow{Name}{tail}{filler}{middle}{filler}{head}

bit for example. Even when TeX stops complaining about how I've defined the arrow, it won't use it; the undefined control sequence error comes up whenever I try and use the arrow. The error message suggests using the PostScript Option, but that also doesn't work. Any ideas?

(For now, I'll try and use a different diagrams tool, but I'd really like to know how to get this to work.) Any help would be much appreciated.

Edit: After doing what Stefan's answer suggested, I'm now trying

\documentclass[a4paper,10pt]{report}
(other packages)
\usepackage[small,nohug]{diagrams}
\diagramstyle[labelstyle=\scriptstyle]
\newarrowtail{-}
\newarrowead{-}
\newarrow{Dots}{-}...{-}
(other pramle etc)
\begin{document}
(blah)
\begin{diagram}
A & \rDots & B
\end{diagram}
(blah)
\end{document}

which works (in so much as TeX now produces the desired diagrams), but now it says:

LaTeX Error: missing \begin{document} ... \newarrow{Dots}{-} ...{-}

So presumably is has a problem with the arrowhead being a -? How to fix that?

(I'm trying to get an arrow looking something like - \cdots - to intidacate an infinite line (currently it just looks like \cdots, but that's fine I suppose).

Answer 1

Here's a minimal example. It defines an arrow called SuperArrow. It uses the arrow to the right by putting \r right before the arrow name.

Global definitions should be done in the preamble, after the required package.

\documentclass{article}
\usepackage{diagrams}
\newarrow{SuperArrow}{>>}...{>>}
\usepackage{amsmath}
\begin{document}
$A \rTo^{\text{ very long arrow }} B$

$A \rSuperArrow^{\text{ very long arrow }} B$
\end{document}

Note: you should correctly install the package. It's published as diagrams.tex, download it, save it into your texmf tree or besides your document and load it by \input{diagrams}, or rename it to diagrams.sty and load it by \usepackage{diagrams}.