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(*
* Exact calculator.
* Copyright (C) 2001 Jean-Christophe FILLIATRE
*
* This software is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License version 2, as published by the Free Software Foundation.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
*
* See the GNU Library General Public License version 2 for more details
* (enclosed in the file LGPL).
*)
(*i $Id: calc.mll,v 1.6 2005/10/26 09:25:06 filliatr Exp $ i*)
{
open Lexing
open Printf
open Cr
(*s Options and parsing of the command-line. *)
let precision = ref 10
let usage = "usage: ecalc [-p prec]
ecalc is a reverse-polish exact calcultator
Copyright (c) 2001- Jean-Christophe Fillitre
This is free software with ABSOLUTELY NO WARRANTY
commands are
k, prec pops the top of stack and uses it as precision
;, p, print displays top of stack
n, popd pops top of stack and displays it
f, show displays the whole stack
pop pops top of stack
c, clear clears the stack
d, dup duplicates top of stack
r, swap swaps the two elements on top of stack
constants are
pi, e
binary operations are
+, -, *, /, log ('x y log' is log_x(y)), pow (or ^)
unary operations are
~ (negation), i (inverse), sqrt (or v), sin, cos, tan, ln, exp,
arcsin, arccos, arctan, sinh, cosh, tanh, arcsinh, arccosh, arctanh
options are"
let speclist =
["-p", Arg.Int (fun n -> precision := n), " set decimal precision"]
let _ = Arg.parse speclist (fun _ -> ()) usage
(*s The stack. *)
let stack = ref []
let push x = stack := x :: !stack
let error msg = printf "%s\n" msg; flush stdout
let pop () = match !stack with
| [] -> invalid_arg "pop"
| x :: l -> stack := l; x
let display_stack () =
List.iter
(fun x -> printf " %s\n" (to_string x !precision))
(List.rev !stack);
flush stdout
(*s Unary and binary operations on the stack. *)
let unop f = push (f (pop ()))
let binop f =
let x2 = pop () in
let x1 = pop () in
push (f x1 x2)
}
(*s Commands are parsed with a lexer. *)
let digit = ['0'-'9']
let constant = digit+ | (digit* '.' digit+ | digit+ '.' digit*)
rule loop = parse
| [' ' '\t' '\n']+
{ loop lexbuf }
| "help"
{ Arg.usage speclist usage; flush stderr }
| "k" | "prec" | "precision"
{ precision := Gmp.Z.int_from (approx (pop ()) 0) }
| "K" | "pushprec"
{ push (of_int !precision) }
| "f" | "show" | "stack"
{ display_stack () }
| "n" | "popd"
{ let x = pop () in
printf " %s\n" (to_string x !precision); flush stdout }
| ";" | "p" | "print"
{ match !stack with
| [] ->
error "<empty stack>"
| x :: _ ->
printf " %s\n" (to_string x !precision); flush stdout }
| "pop"
{ ignore (pop ()) }
| "c" | "clear"
{ stack := [] }
| "d" | "dup"
{ let x = pop () in push x; push x }
| "r" | "swap"
{ let x = pop () in let y = pop () in push x; push y }
| "z" | "pushstackdepth"
{ push (of_int (List.length !stack)) }
| constant
{ push (of_string (lexeme lexbuf)) }
| "pi" { push pi }
| "e" { push e }
| "+" { binop add }
| "-" { binop sub }
| "*" { binop mul }
| "/" { binop div }
| "~" { unop neg }
| "i" { unop inv }
| "sin" { unop sin }
| "cos" { unop cos }
| "tan" { unop tan }
| "arcsin" { unop arcsin }
| "arccos" { unop arccos }
| "arctan" { unop arctan }
| "exp" { unop exp }
| "ln" { unop ln }
| "log" { binop (fun base -> log ~base) }
| "^" | "pow" { binop pow }
| "sinh" { unop sinh }
| "cosh" { unop cosh }
| "tanh" { unop tanh }
| "arcsinh" { unop arcsinh }
| "arccosh" { unop arccosh }
| "arctanh" { unop arctanh }
| "v" | "sqrt" { unop sqrt }
| eof { raise End_of_file }
| _ { raise Parsing.Parse_error }
{
(*s The main program is an infinite loop exiting on [End_of_file]. *)
let _ = Sys.catch_break true
let main () =
let lb = from_channel stdin in
try
while true do
try
loop lb
with
| Sys.Break -> error "<interrupted>"
| Parsing.Parse_error -> error "<syntax error>"
| Invalid_argument "pop" -> error "<empty stack>"
done
with End_of_file ->
flush stdout; exit 0
let _ = Printexc.catch main ()
}
|
