RosettaCodeData/Task/Maze-generation/Tcl/maze-generation.tcl
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2013-04-10 21:29:02 -07:00

97 lines
2.6 KiB
Tcl

package require TclOO; # Or Tcl 8.6
# Helper to pick a random number
proc rand n {expr {int(rand() * $n)}}
# Helper to pick a random element of a list
proc pick list {lindex $list [rand [llength $list]]}
# Helper _function_ to index into a list of lists
proc tcl::mathfunc::idx {v x y} {lindex $v $x $y}
oo::class create maze {
variable x y horiz verti content
constructor {width height} {
set y $width
set x $height
set n [expr {$x * $y - 1}]
if {$n < 0} {error "illegal maze dimensions"}
set horiz [set verti [lrepeat $x [lrepeat $y 0]]]
# This matrix holds the output for the Maze Solving task; not used for generation
set content [lrepeat $x [lrepeat $y " "]]
set unvisited [lrepeat [expr {$x+2}] [lrepeat [expr {$y+2}] 0]]
# Helper to write into a list of lists (with offsets)
proc unvisited= {x y value} {
upvar 1 unvisited u
lset u [expr {$x+1}] [expr {$y+1}] $value
}
lappend stack [set here [list [rand $x] [rand $y]]]
for {set j 0} {$j < $x} {incr j} {
for {set k 0} {$k < $y} {incr k} {
unvisited= $j $k [expr {$here ne [list $j $k]}]
}
}
while {0 < $n} {
lassign $here hx hy
set neighbours {}
foreach {dx dy} {1 0 0 1 -1 0 0 -1} {
if {idx($unvisited, $hx+$dx+1, $hy+$dy+1)} {
lappend neighbours [list [expr {$hx+$dx}] [expr {$hy+$dy}]]
}
}
if {[llength $neighbours]} {
lassign [set here [pick $neighbours]] nx ny
unvisited= $nx $ny 0
if {$nx == $hx} {
lset horiz $nx [expr {min($ny, $hy)}] 1
} else {
lset verti [expr {min($nx, $hx)}] $ny 1
}
lappend stack $here
incr n -1
} else {
set here [lindex $stack end]
set stack [lrange $stack 0 end-1]
}
}
rename unvisited= {}
}
# Maze displayer; takes a maze dictionary, returns a string
method view {} {
set text {}
for {set j 0} {$j < $x*2+1} {incr j} {
set line {}
for {set k 0} {$k < $y*4+1} {incr k} {
if {$j%2 && $k%4==2} {
# At the centre of the cell, put the "content" of the cell
append line [expr {idx($content, $j/2, $k/4)}]
} elseif {$j%2 && ($k%4 || $k && idx($horiz, $j/2, $k/4-1))} {
append line " "
} elseif {$j%2} {
append line "|"
} elseif {0 == $k%4} {
append line "+"
} elseif {$j && idx($verti, $j/2-1, $k/4)} {
append line " "
} else {
append line "-"
}
}
if {!$j} {
lappend text [string replace $line 1 3 " "]
} elseif {$x*2-1 == $j} {
lappend text [string replace $line end end " "]
} else {
lappend text $line
}
}
return [join $text \n]
}
}
# Demonstration
maze create m 11 8
puts [m view]