Functional common lisp version.

clisp_func_pi_dir/Makefile

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+sbcl:
+	PI_ARG=$(PI_ARG) make -f Makefile.sbcl run
+
+clean:
+	rm -f pi.fas pi.lib pi.o

clisp_func_pi_dir/Makefile.sbcl

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+CLISP=sbcl
+CLOPTS=--control-stack-size 256 --script
+
+run: 
+	@$(CLISP) $(CLOPTS) pi.cl $(PI_ARG)
+
+clean:
+	rm -f pi.fas pi.lib pi.o

clisp_func_pi_dir/README.md

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+**Note:** for stack size reasons this version only currently works on SBCL.
+

clisp_func_pi_dir/pi.cl

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+; PI Common LISP example.
+
+; Abstract getting command line arguments.
+; In sbcl the interpreter is an extra argument.
+
+; For CLISP: clisp pi.cl <n>
+; For SBCL: sbcl --script pi.cl <n>
+; For GCL: gcl -f pi.cl <n>
+; For ECL: ecl -shell pi.cl <n>
+
+(defun getargs ()
+  (or
+   #+CLISP *args*
+   #+SBCL (cdr *posix-argv*)
+   #+GCL (cdr si::*command-args*)
+   #+ECL (cdr(cdr(cdr si::*command-args*)))
+   nil))
+
+(defun range (b n j) 
+  (if (>= b n)
+    '()
+    (cons b (range (+ b j) n j))
+  )
+)
+
+
+(defun pc (c) (/ (apply #'+ (map 'list #'(lambda (x) (/ 4 (+ 1 (* x x))))((lambda (n) (range (/ 0.5 n) 1 (/ 1 n))) c))) c))
+
+(defvar n 5000000)
+
+(if (> (list-length(getargs)) 0)
+  (setq n (parse-integer (car (getargs))))
+)
+
+(format t "Calculating PI using~%")
+(format t "  ~a slices~%" n)
+(format t "  1 process~%")
+
+; get-internal-real-time gets time from some arbitrary, implementation 
+; dependent starting point in some fraction of a second.
+(defvar start (get-internal-real-time))
+
+(defvar p (pc n))
+
+; get-internal-real-time is in some platform specific unit which we can find in
+; internal-time-units-per-second
+(defvar stop (get-internal-real-time))
+
+(defvar runt (/ (- stop start) internal-time-units-per-second))
+
+(format t "Obtained value of PI: ~a~%" p)
+
+; We have to print the time with ~f to force a float output.
+(format t "Time taken: ~f seconds~%" runt)

clisp_func_pi_dir/run.sh

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+#!/usr/bin/env bash
+
+# Detect which if any Common LISP implementation we have:
+which sbcl > /dev/null 2>&1
+sbclsuccess=$?
+
+if [ "$sbclsuccess" == "0" ]; then
+  PI_ARG=$1 make -f Makefile.sbcl
+else
+  echo "No Common LISP implementation found."
+  exit 1
+fi