Fossil Wrapper

    puts "Currently defined expansions:"
    dict for {alias expansion} $config::aliases {
        puts [format "%10s -> %s" $alias $expansion]
    }
}

interceptor df|gdf {
   # ----------------------------------------------------------------------

   # a first stab at getting relative revision numbers working with `diff'.

   # should be called as `fsl (g)df -r n' or `fsl (g)df -r n:m' where `n, m' are

   # counting from 0 (initial checkin). This call which is 

   # be mapped to 
   #
   # fsl (g)di -r sha1_n --to sha1_m
   #
   # where `sha1_n, sha1_m' are the sha1 hashes of the respective checkins.
   # further arguments to `diff' are passed through unmodified (hopefully).
   # ----------------------------------------------------------------------
   set hash2num [computeRevnums {}]
   set dim [dict size $hash2num]

   # exchange keys and values in the above dictonary sha1. at the same time,
   # strip the square brackets around the hash value:
   dict for {key val} $hash2num {
      regexp {[[:alnum:]]+} $key sha1
      dict set num2hash [expr {$dim - $val}] $sha1
   }

   # map this interceptor command to `fossil (g)diff'. actually, we use `di'
   # instead of `diff' since only the former will trigger the `diff' filter:
   regsub {^(g?d)f} $params {\1i} params

   # extract the revison number information from `params'. contrary to
   # `fossil' it is acceptable to omit blanks between `-r' and `n:m':
   set rgxrevnum {[[:digit:]]+(:[[:digit:]]+)?}
   set rgx { -r} 
   set rgx { \-r[[:blank:]]*}
   set rgx $rgx$rgxrevnum

   # without `-r' argument we return `params' as is:
   if {![regexp $rgx $params revarg]} {return $params}

   # translate rev. numbers to sha1 hashes and construct the 
   # required `diff' arguments:
   regexp $rgxrevnum $revarg numbers
   set revs [split $numbers :]
   set to {}
   set cnt 0
   set fromto [list from to]
   foreach rev $revs {
      set optarg [lindex $fromto $cnt] 
      # this evals in turn to define variables `from' and `to', respectively,
      # which contain the respective `diff' arguments:
      set $optarg " --$optarg [dict get $num2hash $rev]"
      incr cnt
   } 

   #replace `-r n:m' by the constructed `diff' arguments: 
   regsub $revarg $params $from$to params
   #puts "executing `fossil $params'"
   return $params
}

proc unwrapTimeline records {
#-----------------------------------------------------------------------
# unwrap `fossil timeline' output, putting each checkin on a single
# line. expected input: currently, a list of \n terminated lines.