Data commit

Task/Continued-fraction/Tcl/continued-fraction.tcl

@@ -0,0 +1,41 @@
+package require Tcl 8.6
+
+# Term generators; yield list of pairs
+proc r2 {} {
+    yield {1 1}
+    while 1 {yield {2 1}}
+}
+proc e {} {
+    yield {2 1}
+    while 1 {yield [list [incr n] $n]}
+}
+proc pi {} {
+    set n 0; set a 3
+    while 1 {
+	yield [list $a [expr {(2*[incr n]-1)**2}]]
+	set a 6
+    }
+}
+
+# Continued fraction calculator
+proc cf {generator {termCount 50}} {
+    # Get the chunk of terms we want to work with
+    set terms [list [coroutine cf.c $generator]]
+    while {[llength $terms] < $termCount} {
+	lappend terms [cf.c]
+    }
+    rename cf.c {}
+
+    # Merge the terms to compute the result
+    set val 0.0
+    foreach pair [lreverse $terms] {
+	lassign $pair a b
+	set val [expr {$a + $b/$val}]
+    }
+    return $val
+}
+
+# Demonstration
+puts [cf r2]
+puts [cf e]
+puts [cf pi 250]; # Converges more slowly