Recent changes have been as follows. Distribution dates other than
those shown correspond to changes (usually of documents) not involving
functionality.

2011 10 25 Bugfixes: exec "string" and SVG polyline
2011 05 31 Basic hash and faster search for variables, at the expense of
   increased storage for [ ] blocks. Adjusted svg size parameters.
2011 03 17 Compile #elif for OpenBSD
2011 01 24 Cleanup of dpic -t output.
2010 12 29 Reworked for loops to allow assignment to the loop variable.
2010 12 07 Fixed a bug in psfrag output.
2010 11 28 Bug fix for (string > string)
2010 11 21 Bug fix in expressions of the form string + sprintf(...)
2010 10 31 Optional arrowhead parameter after -> or <- or <->
2010 09 21 Default arrowhead parameter set to 1 to conform to gpic.
2010 07 13 Better justification of stacked text.
2010 06 16 Type 3 arrowheads
2010 05 11 Fix treatment of < character.
2010 05 02 SVG tweaks.
2010 03 15 Curved arc arrowheads for -f, -f, -m, -p, -s and updated -m output.
2010 03 05 Curved arc arrowheads in Postscript and SVG output.
2010 02 19 Fixed an obscure bug with macro args.
2010 02 17 SVG output units changed to px and pt
2010 02 11 -v option to produce SVG output
2010 01 11 Generalized sprintf("string",args) to sprintf(stringexpr,args)
2009 10 30 Tweaked Makefiles for easier Linux installation. Give an error
           message on attempt to set scale parameter to 0.
2009 10 21 Skip white space preceding pic macro arguments;
           e.g. macro( a, <newline> b ) is equivalent to macro(a,b )
2009 07 13 Skip newline after ":" to conform with gpic (see 2008 10 29).
2009 07 09 Added line "shade" for Postscript output, to fill arbitrary polygons.
2009 06 12 Consistent arrowhead on multisegment linear objects.
2009 06 03 More obscure grammar tweaks.
2009 05 29 Slightly streamlined grammar; bugfix for nested x<A,B> constructs.
2009 05 19 Allow "shade" attribute for linear objects with output in PSTricks,
           MPost, and PGF format.  Bugfix for arrowhead.
2009 04 04 Slight change to error message for unknown character.
2009 01 16 Bugfix for continued lines ending in CR LF (PC text) in macros.
2009 01 07 Require filename to contain at least one visible character.
2009 01 04 Redirection added to the print command to allow
           print arg > "filename" or print arg >> "filename" (except safe mode).
2008 10 29 arrowhead = 0 implemented.
2008 10 29 Previously the line A: <newline> was permitted, and was equivalent to
           A: Here but this has been disallowed to conform to other processors.
2008 10 29 More detailed syntax error messages.

For several years prior to mid-2008, there were few changes to dpic except
for the occasional bug fix.