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Task/Fractran/Tcl/fractran-1.tcl

@@ -0,0 +1,49 @@
+package require Tcl 8.6
+
+oo::class create Fractran {
+    variable fracs nco
+    constructor {fractions} {
+	set fracs {}
+	foreach frac $fractions {
+	    if {[regexp {^(\d+)/(\d+),?$} $frac -> num denom]} {
+		lappend fracs $num $denom
+	    } else {
+		return -code error "$frac is not a supported fraction"
+	    }
+	}
+	if {![llength $fracs]} {
+	    return -code error "need at least one fraction"
+	}
+    }
+
+    method execute {n {steps 15}} {
+	set co [coroutine [incr nco] my Generate $n]
+	for {set i 0} {$i < $steps} {incr i} {
+	    lappend result [$co]
+	}
+	catch {rename $co ""}
+	return $result
+    }
+
+    method Step {n} {
+	foreach {num den} $fracs {
+	    if {$n % $den} continue
+	    return [expr {$n * $num / $den}]
+	}
+	return -code break
+    }
+    method Generate {n} {
+	yield [info coroutine]
+	while 1 {
+	    yield $n
+	    set n [my Step $n]
+	}
+	return -code break
+    }
+}
+
+set ft [Fractran new {
+    17/91 78/85 19/51 23/38 29/33 77/29 95/23
+    77/19 1/17 11/13 13/11 15/14 15/2 55/1
+}]
+puts [$ft execute 2]

Task/Fractran/Tcl/fractran-2.tcl

@@ -0,0 +1,12 @@
+oo::objdefine $ft method pow2 {n} {
+    set co [coroutine [incr nco] my Generate 2]
+    set pows {}
+    while {[llength $pows] < $n} {
+	set item [$co]
+	if {($item & ($item-1)) == 0} {
+	    lappend pows $item
+	}
+    }
+    return $pows
+}
+puts [$ft pow2 10]