Beta version of new diagram package

13 Apr 2001


      I have decided to build a new diagram package as a front end to XY-pic. It
is in many ways like my old one, but has much of the power of XY, with a
syntax that is more familiar to people who have used the old one.  This
doubtless contains a number of errors and I would appreciate hearing about
them.  Here is the macro file, diagxy and a document package diaxydoc
follows - it will compile under latex 2e.  I have not tested this package
in plain tex, but I believe it will work.  As for AMS tex, well good luck.  
It has been tried with both the old and new latex.


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\input xy
\xyoption{arrow}
\xyoption{curve}

\newdir{ >}{{ }*!/-9pt/@{>}}
\newdir{< }{!/9pt/@{<}*{ }}

\newbox\label
\newdimen\high
\newdimen\deep
\newdimen\ul
\newcount\deltax
\newcount\deltay
\newcount\xend
\newcount\yend
\newcount\xpos
\newcount\ypos
\newcount\default \default=500
\newif\ifat
\newcount\atcode \atcode=\catcode`\@

\catcode`\@=11
\ul=.01em
\X@xbase=\ul
\Y@ybase=\ul
\let\ifnextchar\@ifnextchar
\catcode`\@=12

\let\bfig\xy
\let\efig\endxy

\def\car#1#2\nil{#1}

\def\morphism(#1,#2)|#3|/#4/<#5,#6>[#7`#8`#9]{%
\xend#1\advance \xend by #5%
\yend#2\advance \yend by #6%
\def\next{#4}%
\ifx\next\empty \atfalse%
\else \def\next{\car#4\nil}%
   \if\next@\attrue \else \atfalse \fi%
\fi%
\ifat
 \def\next{#4}%
 \ifx\next\empty%
  \POS(#1,#2)*+{#7}\ar#4 (\xend,\yend)*+{#8}%
 \else \if#3l%
  \ifnum #6>0%
   \POS(#1,#2)*+{#7}\ar#4^-{#9} (\xend,\yend)*+{#8}%
  \else%
   \POS(#1,#2)*+{#7}\ar#4_-{#9} (\xend,\yend)*+{#8}%
  \fi%
 \else \if#3m%
   \setbox\label=\hbox{\kern .5pt $\labelstyle #9$\kern .5pt}%
   \high=\ht\label \advance\high by 1pt \ht\label=\high%
   \deep=\dp\label \advance\deep by 1pt \dp\label=\deep%
   \POS(#1,#2)*+{#7}\ar#4|-{\box\label} (\xend,\yend)*+{#8}%
 \else \if#3r%
  \ifnum #6<0%
   \POS(#1,#2)*+{#7}\ar#4^-{#9} (\xend,\yend)*+{#8}%
  \else%
   \POS(#1,#2)*+{#7}\ar#4_-{#9} (\xend,\yend)*+{#8}%
  \fi%
 \else \if#3a%
  \ifnum #5>0%
   \POS(#1,#2)*+{#7}\ar#4^-{#9} (\xend,\yend)*+{#8}%
  \else%
   \POS(#1,#2)*+{#7}\ar#4_-{#9} (\xend,\yend)*+{#8}%
  \fi%
 \else \if#3b%
  \ifnum #5<0%
   \POS(#1,#2)*+{#7}\ar#4^-{#9} (\xend,\yend)*+{#8}%
  \else%
   \POS(#1,#2)*+{#7}\ar#4_-{#9} (\xend,\yend)*+{#8}%
  \fi%
 \fi\fi\fi\fi\fi\fi%
\else%
\def\next{#4}%
 \ifx\next\empty%
  \POS(#1,#2)*+{#7}; (\xend,\yend)*+{#8}%
 \else \def\next{#4}%
  \ifx\next\empty%
   \POS(#1,#2)*+{#7}\ar (\xend,\yend)*+{#8}%
 \else \if#3l%
  \ifnum #6>0%
   \POS(#1,#2)*+{#7}\ar@{#4}^-{#9} (\xend,\yend)*+{#8}%
  \else%
   \POS(#1,#2)*+{#7}\ar@{#4}_-{#9} (\xend,\yend)*+{#8}%
  \fi%
 \else \if#3m%
   \setbox\label=\hbox{\kern .5pt $\labelstyle #9$\kern .5pt}%
   \high=\ht\label \advance\high by 1pt \ht\label=\high%
   \deep=\dp\label \advance\deep by 1pt \dp\label=\deep%
   \POS(#1,#2)*+{#7}\ar@{#4}|-{\box\label} (\xend,\yend)*+{#8}%
 \else \if#3r%
  \ifnum #6<0%
   \POS(#1,#2)*+{#7}\ar@{#4}^-{#9} (\xend,\yend)*+{#8}%
  \else%
   \POS(#1,#2)*+{#7}\ar@{#4}_-{#9} (\xend,\yend)*+{#8}%
  \fi%
 \else \if#3a%
  \ifnum #5>0%
   \POS(#1,#2)*+{#7}\ar@{#4}^-{#9} (\xend,\yend)*+{#8}%
  \else%
   \POS(#1,#2)*+{#7}\ar@{#4}_-{#9} (\xend,\yend)*+{#8}%
  \fi%
 \else \if#3b%
  \ifnum #5<0%
   \POS(#1,#2)*+{#7}\ar@{#4}^-{#9} (\xend,\yend)*+{#8}%
  \else%
   \POS(#1,#2)*+{#7}\ar@{#4}_-{#9} (\xend,\yend)*+{#8}%
  \fi%
 \fi\fi\fi\fi\fi\fi\fi%
\fi\ignorespaces}%


\def\location(#1,#2){\xpos=#1\ypos=#2\ignorespaces}
\def\squareplacements|#1`#2`#3`#4|{%
    \def\xa{#1}\def\xb{#2}\def\xc{#3}\def\xd{#4}\ignorespaces}
\def\sizes<#1,#2>{\deltax=#1\deltay=#2\ignorespaces}
\def\squaredata[#1`#2`#3`#4;#5`#6`#7`#8]{%
    \def\nodea{#1}\def\nodeb{#2}\def\nodec{#3}\def\noded{#4}%
    \def\labela{#5}\def\labelb{#6}\def\labelc{#7}\def\labeld{#8}\ignorespaces}

\def\squarepppp(#1)|#2|/#3`#4`#5`#6/<#7>[#8]{%
\location(#1)%
\squareplacements|#2|%
\sizes<#7>%
\squaredata[#8]%
\morphism(\xpos,\ypos)|\xd|/#6/<\deltax,0>[\nodec`\noded`\labeld]
\advance \ypos by \deltay
\morphism(\xpos,\ypos)|\xb|/#4/<0,-\deltay>[\nodea`\nodec`\labelb]
\morphism(\xpos,\ypos)|\xa|/#3/<\deltax,0>[\nodea`\nodeb`\labela]
 \advance \xpos by \deltax
\morphism(\xpos,\ypos)|\xc|/#5/<0,-\deltay>[\nodeb`\noded`\labelc]
\ignorespaces}

\def\square{\ifnextchar({\squarep}{\squarep(0,0)}}
\def\squarep(#1){\ifnextchar|{\squarepp(#1)}{\squarepp(#1)|a`l`r`b|}}
\def\squarepp(#1)|#2|{\ifnextchar/{\squareppp(#1)|#2|}%
    {\squareppp(#1)|#2|/>`>`>`>/}}
\def\squareppp(#1)|#2|/#3`#4`#5`#6/{%
    \ifnextchar<{\squarepppp(#1)|#2|/#3`#4`#5`#6/}%
    {\squarepppp(#1)|#2|/#3`#4`#5`#6/<\default,\default>}}

\def\triplacements|#1`#2`#3|{\def\xa{#1}\def\xb{#2}\def\xc{#3}}
\def\tridata[#1`#2`#3;#4`#5`#6]{%
    \def\nodea{#1}\def\nodeb{#2}\def\nodec{#3}%
    \def\labela{#4}\def\labelb{#5}\def\labelc{#6}}

\def\ptrianglepppp(#1)|#2|/#3`#4`#5/<#6>[#7]{%
\location(#1)%
\triplacements|#2|%
\sizes<#6>%
\tridata[#7]%
\advance\ypos by \deltay
\morphism(\xpos,\ypos)|\xa|/#3/<\deltax,0>[\nodea`\nodeb`\labela]
\morphism(\xpos,\ypos)|\xb|/#4/<0,-\deltay>[\nodea`\nodec`\labelb]
\advance\xpos by \deltax
\morphism(\xpos,\ypos)|\xc|/#5/<-\deltax,-\deltay>[\nodeb`\nodec`\labelc]
\ignorespaces}

\def\ptriangle{\ifnextchar({\ptrianglep}{\ptrianglep(0,0)}}
\def\ptrianglep(#1){\ifnextchar|{\ptrianglepp(#1)}{\ptrianglepp(#1)|a`l`r|}}
\def\ptrianglepp(#1)|#2|{\ifnextchar/{\ptriangleppp(#1)|#2|}%
    {\ptriangleppp(#1)|#2|/>`>`>/}}
\def\ptriangleppp(#1)|#2|/#3`#4`#5/{%
    \ifnextchar<{\ptrianglepppp(#1)|#2|/#3`#4`#5/}%
    {\ptrianglepppp(#1)|#2|/#3`#4`#5/<\default,\default>}}

\def\qtrianglepppp(#1)|#2|/#3`#4`#5/<#6>[#7]{%
\location(#1)%
\triplacements|#2|%
\sizes<#6>%
\tridata[#7]%
\advance\ypos by \deltay
\morphism(\xpos,\ypos)|\xa|/#3/<\deltax,0>[\nodea`\nodeb`\labela]
\morphism(\xpos,\ypos)|\xb|/#4/<\deltax,-\deltay>[\nodea`\nodec`\labelb]
\advance\xpos by \deltax
\morphism(\xpos,\ypos)|\xc|/#5/<0,-\deltay>[\nodeb`\nodec`\labelc]
\ignorespaces}

\def\qtriangle{\ifnextchar({\qtrianglep}{\qtrianglep(0,0)}}
\def\qtrianglep(#1){\ifnextchar|{\qtrianglepp(#1)}{\qtrianglepp(#1)|a`l`r|}}
\def\qtrianglepp(#1)|#2|{\ifnextchar/{\qtriangleppp(#1)|#2|}%
    {\qtriangleppp(#1)|#2|/>`>`>/}}
\def\qtriangleppp(#1)|#2|/#3`#4`#5/{%
    \ifnextchar<{\qtrianglepppp(#1)|#2|/#3`#4`#5/}%
    {\qtrianglepppp(#1)|#2|/#3`#4`#5/<\default,\default>}}

\def\dtrianglepppp(#1)|#2|/#3`#4`#5/<#6>[#7]{%
\location(#1)%
\triplacements|#2|%
\sizes<#6>%
\tridata[#7]%
\morphism(\xpos,\ypos)|\xc|/#5/<\deltax,0>[\nodeb`\nodec`\labelc]
\advance\ypos by \deltay\advance \xpos by \deltax
\morphism(\xpos,\ypos)|\xa|/#3/<-\deltax,-\deltay>[\nodea`\nodeb`\labela]
\morphism(\xpos,\ypos)|\xb|/#4/<0,-\deltay>[\nodea`\nodec`\labelb]
\ignorespaces}

\def\dtriangle{\ifnextchar({\dtrianglep}{\dtrianglep(0,0)}}
\def\dtrianglep(#1){\ifnextchar|{\dtrianglepp(#1)}{\dtrianglepp(#1)|l`r`b|}}
\def\dtrianglepp(#1)|#2|{\ifnextchar/{\dtriangleppp(#1)|#2|}%
    {\dtriangleppp(#1)|#2|/>`>`>/}}
\def\dtriangleppp(#1)|#2|/#3`#4`#5/{%
    \ifnextchar<{\dtrianglepppp(#1)|#2|/#3`#4`#5/}%
    {\dtrianglepppp(#1)|#2|/#3`#4`#5/<\default,\default>}}

\def\btrianglepppp(#1)|#2|/#3`#4`#5/<#6>[#7]{%
\location(#1)%
\triplacements|#2|%
\sizes<#6>%
\tridata[#7]%
\morphism(\xpos,\ypos)|\xc|/#5/<\deltax,0>[\nodeb`\nodec`\labelc]
\advance\ypos by \deltay
\morphism(\xpos,\ypos)|\xa|/#3/<0,-\deltay>[\nodea`\nodeb`\labela]
\morphism(\xpos,\ypos)|\xb|/#4/<\deltax,-\deltay>[\nodea`\nodec`\labelb]
\ignorespaces}

\def\btriangle{\ifnextchar({\btrianglep}{\btrianglep(0,0)}}
\def\btrianglep(#1){\ifnextchar|{\btrianglepp(#1)}{\btrianglepp(#1)|l`r`b|}}
\def\btrianglepp(#1)|#2|{\ifnextchar/{\btriangleppp(#1)|#2|}%
    {\btriangleppp(#1)|#2|/>`>`>/}}
\def\btriangleppp(#1)|#2|/#3`#4`#5/{%
    \ifnextchar<{\btrianglepppp(#1)|#2|/#3`#4`#5/}%
    {\btrianglepppp(#1)|#2|/#3`#4`#5/<\default,\default>}}

\def\Atrianglepppp(#1)|#2|/#3`#4`#5/<#6>[#7]{%
\location(#1)%
\triplacements|#2|%
\sizes<#6>%
\tridata[#7]%
{\multiply\deltax by 2%
\morphism(\xpos,\ypos)|\xc|/#5/<\deltax,0>[\nodeb`\nodec`\labelc]}%
\advance\ypos by \deltay\advance\xpos by \deltax
\morphism(\xpos,\ypos)|\xa|/#3/<-\deltax,-\deltay>[\nodea`\nodeb`\labela]
\morphism(\xpos,\ypos)|\xb|/#4/<\deltax,-\deltay>[\nodea`\nodec`\labelb]
\ignorespaces}

\def\Atriangle{\ifnextchar({\Atrianglep}{\Atrianglep(0,0)}}
\def\Atrianglep(#1){\ifnextchar|{\Atrianglepp(#1)}{\Atrianglepp(#1)|l`r`b|}}
\def\Atrianglepp(#1)|#2|{\ifnextchar/{\Atriangleppp(#1)|#2|}%
    {\Atriangleppp(#1)|#2|/>`>`>/}}
\def\Atriangleppp(#1)|#2|/#3`#4`#5/{%
    \ifnextchar<{\Atrianglepppp(#1)|#2|/#3`#4`#5/}%
    {\Atrianglepppp(#1)|#2|/#3`#4`#5/<\default,\default>}}

\def\Vtrianglepppp(#1)|#2|/#3`#4`#5/<#6>[#7]{%
\location(#1)%
\triplacements|#2|%
\sizes<#6>%
\tridata[#7]%
\advance\ypos by \deltay
\morphism(\xpos,\ypos)|\xb|/#4/<\deltax,-\deltay>[\nodea`\nodec`\labelb]
{\multiply\deltax by 2%
\morphism(\xpos,\ypos)|\xa|/#3/<\deltax,0>[\nodea`\nodeb`\labela]%
\global\advance\xpos by \deltax}%
\morphism(\xpos,\ypos)|\xc|/#5/<-\deltax,-\deltay>[\nodeb`\nodec`\labelc]
\ignorespaces}

\def\Vtriangle{\ifnextchar({\Vtrianglep}{\Vtrianglep(0,0)}}
\def\Vtrianglep(#1){\ifnextchar|{\Vtrianglepp(#1)}{\Vtrianglepp(#1)|a`l`b|}}
\def\Vtrianglepp(#1)|#2|{\ifnextchar/{\Vtriangleppp(#1)|#2|}%
    {\Vtriangleppp(#1)|#2|/>`>`>/}}
\def\Vtriangleppp(#1)|#2|/#3`#4`#5/{%
    \ifnextchar<{\Vtrianglepppp(#1)|#2|/#3`#4`#5/}%
    {\Vtrianglepppp(#1)|#2|/#3`#4`#5/<\default,\default>}}

\def\Ctrianglepppp(#1)|#2|/#3`#4`#5/<#6>[#7]{%
\location(#1)%
\triplacements|#2|%
\sizes<#6>%
\tridata[#7]%
\advance \ypos by \deltay
\morphism(\xpos,\ypos)|\xc|/#5/<\deltax,-\deltay>[\nodeb`\nodec`\labelc]
\advance\ypos by \deltay \advance \xpos by \deltax
\morphism(\xpos,\ypos)|\xa|/#3/<-\deltax,-\deltay>[\nodea`\nodeb`\labela]
\multiply\deltay by 2%
\morphism(\xpos,\ypos)|\xb|/#4/<0,-\deltay>[\nodea`\nodec`\labelb]%
\ignorespaces}

\def\Ctriangle{\ifnextchar({\Ctrianglep}{\Ctrianglep(0,0)}}
\def\Ctrianglep(#1){\ifnextchar|{\Ctrianglepp(#1)}{\Ctrianglepp(#1)|a`r`b|}}
\def\Ctrianglepp(#1)|#2|{\ifnextchar/{\Ctriangleppp(#1)|#2|}%
    {\Ctriangleppp(#1)|#2|/>`>`>/}}
\def\Ctriangleppp(#1)|#2|/#3`#4`#5/{%
    \ifnextchar<{\Ctrianglepppp(#1)|#2|/#3`#4`#5/}%
    {\Ctrianglepppp(#1)|#2|/#3`#4`#5/<\default,\default>}}

\def\Dtrianglepppp(#1)|#2|/#3`#4`#5/<#6>[#7]{%
\location(#1)%
\triplacements|#2|%
\sizes<#6>%
\tridata[#7]%
\advance\xpos by \deltax \advance\ypos by \deltay
\morphism(\xpos,\ypos)|\xc|/#5/<-\deltax,-\deltay>[\nodeb`\nodec`\labelc]
\advance\xpos by -\deltax \advance\ypos by \deltay
\morphism(\xpos,\ypos)|\xb|/#4/<\deltax,-\deltay>[\nodea`\nodeb`\labelb]%
\multiply \deltay by 2
\morphism(\xpos,\ypos)|\xa|/#3/<0,-\deltay>[\nodea`\nodec`\labela]%
\ignorespaces}

\def\Dtriangle{\ifnextchar({\Dtrianglep}{\Dtrianglep(0,0)}}
\def\Dtrianglep(#1){\ifnextchar|{\Dtrianglepp(#1)}{\Dtrianglepp(#1)|a`l`b|}}
\def\Dtrianglepp(#1)|#2|{\ifnextchar/{\Dtriangleppp(#1)|#2|}%
    {\Dtriangleppp(#1)|#2|/>`>`>/}}
\def\Dtriangleppp(#1)|#2|/#3`#4`#5/{%
    \ifnextchar<{\Dtrianglepppp(#1)|#2|/#3`#4`#5/}%
    {\Dtrianglepppp(#1)|#2|/#3`#4`#5/<\default,\default>}}

\def\tripairplacements|#1`#2`#3`#4`#5|{\def\xa{#1}\def\xb{#2}\def\xc{#3}%
\def\xd{#4}\def\xe{#5}}
\def\tripairdata[#1`#2`#3`#4;#5`#6`#7`#8`#9]{%
 \def\nodea{#1}\def\nodeb{#2}\def\nodec{#3}\def\noded{#4}%
 \def\labela{#5}\def\labelb{#6}\def\labelc{#7}\def\labeld{#8}\def\labele{#9}}


\def\Atrianglepairpppp(#1)|#2|/#3`#4`#5`#6`#7/<#8>[#9]{%
\location(#1)%
\tripairplacements|#2|%
\sizes<#8>%
\tripairdata[#9]%
\morphism(\xpos,\ypos)|\xd|/#6/<\deltax,0>[\nodeb`\nodec`\labeld]%
\advance\xpos by \deltax
\morphism(\xpos,\ypos)|\xe|/#7/<\deltax,0>[\nodec`\noded`\labele]%
\advance\ypos by \deltay
\morphism(\xpos,\ypos)|\xa|/#3/<-\deltax,-\deltay>[\nodea`\nodeb`\labela]%
\morphism(\xpos,\ypos)|\xb|/#4/<0,-\deltay>[\nodea`\nodec`\labelb]%
\morphism(\xpos,\ypos)|\xc|/#5/<\deltax,-\deltay>[\nodea`\noded`\labelc]%
\ignorespaces}

\def\Atrianglepair{\ifnextchar({\Atrianglepairp}{\Atrianglepairp(0,0)}}%
\def\Atrianglepairp(#1){\ifnextchar|{\Atrianglepairpp(#1)}%
{\Atrianglepairpp(#1)|l`m`r`b`b|}}%
\def\Atrianglepairpp(#1)|#2|{\ifnextchar/{\Atrianglepairppp(#1)|#2|}%
    {\Atrianglepairppp(#1)|#2|/>`>`>`>`>/}}%
\def\Atrianglepairppp(#1)|#2|/#3`#4`#5`#6`#7/{%
    \ifnextchar<{\Atrianglepairpppp(#1)|#2|/#3`#4`#5`#6`#7/}%
    {\Atrianglepairpppp(#1)|#2|/#3`#4`#5`#6`#7/<\default,\default>}}%

\def\Vtrianglepairpppp(#1)|#2|/#3`#4`#5`#6`#7/<#8>[#9]{%
\location(#1)%
\tripairplacements|#2|%
\sizes<#8>%
\tripairdata[#9]%
\advance\ypos by \deltay
\morphism(\xpos,\ypos)|\xa|/#3/<\deltax,0>[\nodea`\nodeb`\labela]%
\morphism(\xpos,\ypos)|\xc|/#5/<\deltax,-\deltay>[\nodea`\noded`\labelc]%
\advance\xpos by \deltax
\morphism(\xpos,\ypos)|\xb|/#4/<\deltax,0>[\nodeb`\nodec`\labelb]%
\morphism(\xpos,\ypos)|\xd|/#6/<0,-\deltay>[\nodeb`\noded`\labeld]%
\advance\xpos by \deltax
\morphism(\xpos,\ypos)|\xe|/#7/<-\deltax,-\deltay>[\nodec`\noded`\labele]%
\ignorespaces}

\def\Vtrianglepair{\ifnextchar({\Vtrianglepairp}{\Vtrianglepairp(0,0)}}%
\def\Vtrianglepairp(#1){\ifnextchar|{\Vtrianglepairpp(#1)}%
{\Vtrianglepairpp(#1)|a`a`l`m`r|}}%
\def\Vtrianglepairpp(#1)|#2|{\ifnextchar/{\Vtrianglepairppp(#1)|#2|}%
    {\Vtrianglepairppp(#1)|#2|/>`>`>`>`>/}}%
\def\Vtrianglepairppp(#1)|#2|/#3`#4`#5`#6`#7/{%
    \ifnextchar<{\Vtrianglepairpppp(#1)|#2|/#3`#4`#5`#6`#7/}%
    {\Vtrianglepairpppp(#1)|#2|/#3`#4`#5`#6`#7/<\default,\default>}}%

\def\Ctrianglepairpppp(#1)|#2|/#3`#4`#5`#6`#7/<#8>[#9]{%
\location(#1)%
\tripairplacements|#2|%
\sizes<#8>%
\tripairdata[#9]%
\advance\ypos by \deltay
\morphism(\xpos,\ypos)|\xe|/#7/<0,-\deltay>[\nodec`\noded`\labele]%
\advance\xpos by -\deltax
\morphism(\xpos,\ypos)|\xc|/#5/<\deltax,0>[\nodeb`\nodec`\labelc]%
\morphism(\xpos,\ypos)|\xd|/#6/<\deltax,-\deltay>[\nodeb`\noded`\labeld]%
\advance\ypos by \deltay
\advance\xpos by \deltax
\morphism(\xpos,\ypos)|\xa|/#3/<-\deltax,-\deltay>[\nodea`\nodeb`\labela]%
\morphism(\xpos,\ypos)|\xb|/#4/<0,-\deltay>[\nodea`\nodec`\labelb]%
\ignorespaces}

\def\Ctrianglepair{\ifnextchar({\Ctrianglepairp}{\Ctrianglepairp(0,0)}}%
\def\Ctrianglepairp(#1){\ifnextchar|{\Ctrianglepairpp(#1)}%
{\Ctrianglepairpp(#1)|l`r`m`l`r|}}%
\def\Ctrianglepairpp(#1)|#2|{\ifnextchar/{\Ctrianglepairppp(#1)|#2|}%
    {\Ctrianglepairppp(#1)|#2|/>`>`>`>`>/}}%
\def\Ctrianglepairppp(#1)|#2|/#3`#4`#5`#6`#7/{%
    \ifnextchar<{\Ctrianglepairpppp(#1)|#2|/#3`#4`#5`#6`#7/}%
    {\Ctrianglepairpppp(#1)|#2|/#3`#4`#5`#6`#7/<\default,\default>}}%

\def\Dtrianglepairpppp(#1)|#2|/#3`#4`#5`#6`#7/<#8>[#9]{%
\location(#1)%
\tripairplacements|#2|%
\sizes<#8>%
\tripairdata[#9]%
\advance\ypos by \deltay
\morphism(\xpos,\ypos)|\xc|/#5/<\deltax,0>[\nodeb`\nodec`\labelc]%
\morphism(\xpos,\ypos)|\xd|/#6/<0,-\deltay>[\nodeb`\noded`\labeld]%
\advance\ypos by \deltay
\morphism(\xpos,\ypos)|\xa|/#3/<0,-\deltay>[\nodea`\nodeb`\labela]%
\morphism(\xpos,\ypos)|\xb|/#4/<\deltax,-\deltay>[\nodea`\nodec`\labelb]%
\advance\ypos by -\deltay
\advance\xpos by \deltax
\morphism(\xpos,\ypos)|\xe|/#7/<-\deltax,-\deltay>[\nodec`\noded`\labele]%
\ignorespaces}

\def\Dtrianglepair{\ifnextchar({\Dtrianglepairp}{\Dtrianglepairp(0,0)}}%
\def\Dtrianglepairp(#1){\ifnextchar|{\Dtrianglepairpp(#1)}%
{\Dtrianglepairpp(#1)|l`r`m`l`r|}}%
\def\Dtrianglepairpp(#1)|#2|{\ifnextchar/{\Dtrianglepairppp(#1)|#2|}%
    {\Dtrianglepairppp(#1)|#2|/>`>`>`>`>/}}%
\def\Dtrianglepairppp(#1)|#2|/#3`#4`#5`#6`#7/{%
    \ifnextchar<{\Dtrianglepairpppp(#1)|#2|/#3`#4`#5`#6`#7/}%
    {\Dtrianglepairpppp(#1)|#2|/#3`#4`#5`#6`#7/<\default,\default>}}%
\catcode`\@=\atcode

\def\place(#1,#2)[#3]{\POS(#1,#2)*+{#3}}

\def\pullback#1]#2]{\square#1]\trident#2]}
\def\tridentdata[#1;#2`#3`#4]{\def\nodee{#1}\def\labele{#2}%
   \def\labelf{#3}\def\labelg{#4}}
\def\trident{\ifnextchar|{\tridentp}{\tridentp|a`m`b|}}

\def\tridentp|#1|{\ifnextchar/{\tridentpp|#1|}{\tridentpp|#1|/{>}`{>}`{>}/}}

\def\tridentpp|#1|/#2/{\ifnextchar<{\tridentppp|#1|/#2/}%
  {\tridentppp|#1|/#2/<500,500>}}

\def\tridentppp|#1`#2`#3|/#4`#5`#6/<#7,#8>[#9]{%
\tridentdata[#9]%
\advance \xpos by -\deltax
\advance \xpos by -#7\advance \ypos by #8%
{\advance\deltax by #7%
\morphism(\xpos,\ypos)|#1|/#4/<\deltax,-#8>[\nodee`\nodeb`\labele]}%
\morphism(\xpos,\ypos)|#2|/#5/<#7,-#8>[\nodee`\nodea`\labelf]%
\advance\deltay by #8%
\morphism(\xpos,\ypos)|#3|/#6/<#7,-\deltay>[\nodee`\nodec`\labelg]}

Beta version of new diagram package

Michael Barr