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Diffstat (limited to 'usr.bin/sed/TEST/hanoi.sed')
-rw-r--r-- | usr.bin/sed/TEST/hanoi.sed | 102 |
1 files changed, 102 insertions, 0 deletions
diff --git a/usr.bin/sed/TEST/hanoi.sed b/usr.bin/sed/TEST/hanoi.sed new file mode 100644 index 0000000..d29c648 --- /dev/null +++ b/usr.bin/sed/TEST/hanoi.sed @@ -0,0 +1,102 @@ +# Towers of Hanoi in sed. +# +# @(#)hanoi.sed 8.1 (Berkeley) 6/6/93 +# +# +# Ex: +# Run "sed -f hanoi.sed", and enter: +# +# :abcd: : :<CR><CR> +# +# note -- TWO carriage returns, a peculiarity of sed), this will output the +# sequence of states involved in moving 4 rings, the largest called "a" and +# the smallest called "d", from the first to the second of three towers, so +# that the rings on any tower at any time are in descending order of size. +# You can start with a different arrangement and a different number of rings, +# say :ce:b:ax: and it will give the shortest procedure for moving them all +# to the middle tower. The rules are: the names of the rings must all be +# lower-case letters, they must be input within 3 fields (representing the +# towers) and delimited by 4 colons, such that the letters within each field +# are in alphabetical order (i.e. rings are in descending order of size). +# +# For the benefit of anyone who wants to figure out the script, an "internal" +# line of the form +# b:0abx:1a2b3 :2 :3x2 +# has the following meaning: the material after the three markers :1, :2, +# and :3 represents the three towers; in this case the current set-up is +# ":ab : :x :". The numbers after a, b and x in these fields indicate +# that the next time it gets a chance, it will move a to tower 2, move b +# to tower 3, and move x to tower 2. The string after :0 just keeps track +# of the alphabetical order of the names of the rings. The b at the +# beginning means that it is now dealing with ring b (either about to move +# it, or re-evaluating where it should next be moved to). +# +# Although this version is "limited" to 26 rings because of the size of the +# alphabet, one could write a script using the same idea in which the rings +# were represented by arbitrary [strings][within][brackets], and in place of +# the built-in line of the script giving the order of the letters of the +# alphabet, it would accept from the user a line giving the ordering to be +# assumed, e.g. [ucbvax][decvax][hplabs][foo][bar]. +# +# George Bergman +# Math, UC Berkeley 94720 USA + +# cleaning, diagnostics +s/ *//g +/^$/d +/[^a-z:]/{a\ +Illegal characters: use only a-z and ":". Try again. +d +} +/^:[a-z]*:[a-z]*:[a-z]*:$/!{a\ +Incorrect format: use\ +\ : string1 : string2 : string3 :<CR><CR>\ +Try again. +d +} +/\([a-z]\).*\1/{a\ +Repeated letters not allowed. Try again. +d +} +# initial formatting +h +s/[a-z]/ /g +G +s/^:\( *\):\( *\):\( *\):\n:\([a-z]*\):\([a-z]*\):\([a-z]*\):$/:1\4\2\3:2\5\1\3:3\6\1\2:0/ +s/[a-z]/&2/g +s/^/abcdefghijklmnopqrstuvwxyz/ +:a +s/^\(.\).*\1.*/&\1/ +s/.// +/^[^:]/ba +s/\([^0]*\)\(:0.*\)/\2\1:/ +s/^[^0]*0\(.\)/\1&/ +:b +# outputting current state without markers +h +s/.*:1/:/ +s/[123]//gp +g +:c +# establishing destinations +/^\(.\).*\1:1/td +/^\(.\).*:1[^:]*\11/s/^\(.\)\(.*\1\([a-z]\).*\)\3./\3\2\31/ +/^\(.\).*:1[^:]*\12/s/^\(.\)\(.*\1\([a-z]\).*\)\3./\3\2\33/ +/^\(.\).*:1[^:]*\13/s/^\(.\)\(.*\1\([a-z]\).*\)\3./\3\2\32/ +/^\(.\).*:2[^:]*\11/s/^\(.\)\(.*\1\([a-z]\).*\)\3./\3\2\33/ +/^\(.\).*:2[^:]*\12/s/^\(.\)\(.*\1\([a-z]\).*\)\3./\3\2\32/ +/^\(.\).*:2[^:]*\13/s/^\(.\)\(.*\1\([a-z]\).*\)\3./\3\2\31/ +/^\(.\).*:3[^:]*\11/s/^\(.\)\(.*\1\([a-z]\).*\)\3./\3\2\32/ +/^\(.\).*:3[^:]*\12/s/^\(.\)\(.*\1\([a-z]\).*\)\3./\3\2\31/ +/^\(.\).*:3[^:]*\13/s/^\(.\)\(.*\1\([a-z]\).*\)\3./\3\2\33/ +bc +# iterate back to find smallest out-of-place ring +:d +s/^\(.\)\(:0[^:]*\([^:]\)\1.*:\([123]\)[^:]*\1\)\4/\3\2\4/ +td +# move said ring (right, resp. left) +s/^\(.\)\(.*\)\1\([23]\)\(.*:\3[^ ]*\) /\1\2 \4\1\3/ +s/^\(.\)\(.*:\([12]\)[^ ]*\) \(.*\)\1\3/\1\2\1\3\4 / +tb +s/.*/Done! Try another, or end with ^D./p +d |