diff options
Diffstat (limited to 'test/pending/run/lisp.scala')
-rw-r--r-- | test/pending/run/lisp.scala | 518 |
1 files changed, 0 insertions, 518 deletions
diff --git a/test/pending/run/lisp.scala b/test/pending/run/lisp.scala deleted file mode 100644 index f3687ea1bb..0000000000 --- a/test/pending/run/lisp.scala +++ /dev/null @@ -1,518 +0,0 @@ -//############################################################################ -// Lisp interpreter -//############################################################################ - -//############################################################################ -// Lisp Scanner - -class LispTokenizer(s: String) extends Iterator[String] { - private var i = 0; - private def isDelimiter(ch: Char) = ch <= ' ' || ch == '(' || ch == ')' - def hasNext: Boolean = { - while (i < s.length() && s.charAt(i) <= ' ') i += 1 - i < s.length() - } - def next: String = - if (hasNext) { - val start = i - if (isDelimiter(s charAt i)) i += 1 - else - do i = i + 1 - while (!isDelimiter(s charAt i)) - s.substring(start, i) - } else sys.error("premature end of string") -} - -//############################################################################ -// Lisp Interface - -trait Lisp { - type Data - - def string2lisp(s: String): Data - def lisp2string(s: Data): String - - def evaluate(d: Data): Data - // !!! def evaluate(s: String): Data = evaluate(string2lisp(s)) - def evaluate(s: String): Data -} - -//############################################################################ -// Lisp Implementation Using Case Classes - -object LispCaseClasses extends Lisp { - - import List.range - - trait Data { - def elemsToString(): String = toString(); - } - case class CONS(car: Data, cdr: Data) extends Data { - override def toString() = "(" + elemsToString() + ")"; - override def elemsToString() = car.toString() + (cdr match { - case NIL() => "" - case _ => " " + cdr.elemsToString(); - }) - } - case class NIL() extends Data { // !!! use case object - override def toString() = "()"; - } - case class SYM(name: String) extends Data { - override def toString() = name; - } - case class NUM(x: Int) extends Data { - override def toString() = x.toString(); - } - case class STR(x: String) extends Data { - override def toString() = "\"" + x + "\""; - } - case class FUN(f: List[Data] => Data) extends Data { - override def toString() = "<fn>"; - } - - def list(): Data = - NIL(); - def list(x0: Data): Data = - CONS(x0, NIL()); - def list(x0: Data, x1: Data): Data = - CONS(x0, list(x1)); - def list(x0: Data, x1: Data, x2: Data): Data = - CONS(x0, list(x1, x2)); - def list(x0: Data, x1: Data, x2: Data, x3: Data): Data = - CONS(x0, list(x1, x2, x3)); - def list(x0: Data, x1: Data, x2: Data, x3: Data, x4: Data): Data = - CONS(x0, list(x1, x2, x3, x4)); - def list(x0: Data, x1: Data, x2: Data, x3: Data, x4: Data, x5: Data): Data = - CONS(x0, list(x1, x2, x3, x4, x5)); - def list(x0: Data, x1: Data, x2: Data, x3: Data, x4: Data, x5: Data, - x6: Data): Data = - CONS(x0, list(x1, x2, x3, x4, x5, x6)); - def list(x0: Data, x1: Data, x2: Data, x3: Data, x4: Data, x5: Data, - x6: Data, x7: Data): Data = - CONS(x0, list(x1, x2, x3, x4, x5, x6, x7)); - def list(x0: Data, x1: Data, x2: Data, x3: Data, x4: Data, x5: Data, - x6: Data, x7: Data, x8: Data): Data = - CONS(x0, list(x1, x2, x3, x4, x5, x6, x7, x8)); - def list(x0: Data, x1: Data, x2: Data, x3: Data, x4: Data, x5: Data, - x6: Data, x7: Data, x8: Data, x9: Data): Data = - CONS(x0, list(x1, x2, x3, x4, x5, x6, x7, x8, x9)); - - var curexp: Data = null - var trace: Boolean = false - var indent: Int = 0 - - def lispError[a](msg: String): a = - sys.error("error: " + msg + "\n" + curexp); - - trait Environment { - def lookup(n: String): Data; - def extendRec(name: String, expr: Environment => Data) = - new Environment { - def lookup(n: String): Data = - if (n == name) expr(this) else Environment.this.lookup(n); - } - def extend(name: String, v: Data) = extendRec(name, (env1 => v)); - } - val EmptyEnvironment = new Environment { - def lookup(n: String): Data = lispError("undefined: " + n); - } - - def toList(x: Data): List[Data] = x match { - case NIL() => List() - case CONS(y, ys) => y :: toList(ys) - case _ => lispError("malformed list: " + x); - } - - def toBoolean(x: Data) = x match { - case NUM(0) => false - case _ => true - } - - def normalize(x: Data): Data = x match { - case CONS(SYM("def"), - CONS(CONS(SYM(name), args), CONS(body, CONS(expr, NIL())))) => - normalize(list(SYM("def"), - SYM(name), list(SYM("lambda"), args, body), expr)) - case CONS(SYM("cond"), CONS(CONS(SYM("else"), CONS(expr, NIL())),NIL())) => - normalize(expr) - case CONS(SYM("cond"), CONS(CONS(test, CONS(expr, NIL())), rest)) => - normalize(list(SYM("if"), test, expr, CONS(SYM("cond"), rest))) - case CONS(h, t) => CONS(normalize(h), normalize(t)) - case _ => x - } - - def eval(x: Data, env: Environment): Data = { - val prevexp = curexp; - curexp = x; - if (trace) { - for (x <- range(1, indent)) Console.print(" "); - Console.println("===> " + x); - indent = indent + 1; - } - val result = eval1(x, env); - if (trace) { - indent = indent - 1; - for (x <- range(1, indent)) Console.print(" "); - Console.println("<=== " + result); - } - curexp = prevexp; - result - } - - def eval1(x: Data, env: Environment): Data = x match { - case SYM(name) => - env lookup name - case CONS(SYM("def"), CONS(SYM(name), CONS(y, CONS(z, NIL())))) => - eval(z, env.extendRec(name, (env1 => eval(y, env1)))) - case CONS(SYM("val"), CONS(SYM(name), CONS(y, CONS(z, NIL())))) => - eval(z, env.extend(name, eval(y, env))) - case CONS(SYM("lambda"), CONS(params, CONS(y, NIL()))) => - mkLambda(params, y, env) - case CONS(SYM("if"), CONS(c, CONS(t, CONS(e, NIL())))) => - if (toBoolean(eval(c, env))) eval(t, env) else eval(e, env) - case CONS(SYM("quote"), CONS(x, NIL())) => - x - case CONS(y, xs) => - apply(eval(y, env), toList(xs) map (x => eval(x, env))) - case NUM(_) => x - case STR(_) => x - case FUN(_) => x - case _ => - lispError("illegal term") - } - - def apply(fn: Data, args: List[Data]): Data = fn match { - case FUN(f) => f(args); - case _ => lispError("application of non-function: " + fn); - } - - def mkLambda(params: Data, expr: Data, env: Environment): Data = { - - def extendEnv(env: Environment, - ps: List[String], args: List[Data]): Environment = - Pair(ps, args) match { - case Pair(List(), List()) => - env - case Pair(p :: ps1, arg :: args1) => - extendEnv(env.extend(p, arg), ps1, args1) - case _ => - lispError("wrong number of arguments") - } - - val ps: List[String] = toList(params) map { - case SYM(name) => name - case _ => sys.error("illegal parameter list"); - } - - FUN(args => eval(expr, extendEnv(env, ps, args))) - } - - val globalEnv = EmptyEnvironment - .extend("=", FUN({ - case List(NUM(arg1),NUM(arg2)) => NUM(if (arg1 == arg2) 1 else 0) - case List(STR(arg1),STR(arg2)) => NUM(if (arg1 == arg2) 1 else 0)})) - .extend("+", FUN({ - case List(NUM(arg1),NUM(arg2)) => NUM(arg1 + arg2) - case List(STR(arg1),STR(arg2)) => STR(arg1 + arg2)})) - .extend("-", FUN({ - case List(NUM(arg1),NUM(arg2)) => NUM(arg1 - arg2)})) - .extend("*", FUN({ - case List(NUM(arg1),NUM(arg2)) => NUM(arg1 * arg2)})) - .extend("/", FUN({ - case List(NUM(arg1),NUM(arg2)) => NUM(arg1 / arg2)})) - .extend("car", FUN({ - case List(CONS(x, xs)) => x})) - .extend("cdr", FUN({ - case List(CONS(x, xs)) => xs})) - .extend("null?", FUN({ - case List(NIL()) => NUM(1) - case _ => NUM(0)})) - .extend("cons", FUN({ - case List(x, y) => CONS(x, y)})); - - def evaluate(x: Data): Data = eval(normalize(x), globalEnv); - def evaluate(s: String): Data = evaluate(string2lisp(s)); - - def string2lisp(s: String): Data = { - val it = new LispTokenizer(s); - def parseExpr(token: String): Data = { - if (token == "(") parseList - else if (token == ")") sys.error("unbalanced parentheses") - else if ('0' <= token.charAt(0) && token.charAt(0) <= '9') - NUM(token.toInt) - else if (token.charAt(0) == '\"' && token.charAt(token.length()-1)=='\"') - STR(token.substring(1,token.length() - 1)) - else SYM(token) - } - def parseList: Data = { - val token = it.next; - if (token == ")") NIL() else CONS(parseExpr(token), parseList) - } - parseExpr(it.next) - } - - def lisp2string(d: Data): String = d.toString(); -} - -//############################################################################ -// Lisp Implementation Using Any - -object LispAny extends Lisp { - - import List._; - - type Data = Any; - - case class Lambda(f: List[Data] => Data); - - var curexp: Data = null; - var trace: Boolean = false; - var indent: Int = 0; - - def lispError[a](msg: String): a = - sys.error("error: " + msg + "\n" + curexp); - - trait Environment { - def lookup(n: String): Data; - def extendRec(name: String, expr: Environment => Data) = - new Environment { - def lookup(n: String): Data = - if (n == name) expr(this) else Environment.this.lookup(n); - } - def extend(name: String, v: Data) = extendRec(name, (env1 => v)); - } - val EmptyEnvironment = new Environment { - def lookup(n: String): Data = lispError("undefined: " + n); - } - - def asList(x: Data): List[Data] = x match { - case y: List[_] => y - case _ => lispError("malformed list: " + x) - } - - def asInt(x: Data): Int = x match { - case y: Int => y - case _ => lispError("not an integer: " + x) - } - - def asString(x: Data): String = x match { - case y: String => y - case _ => lispError("not a string: " + x) - } - - def asBoolean(x: Data): Boolean = x != 0 - - def normalize(x: Data): Data = x match { - case 'and :: x :: y :: Nil => - normalize('if :: x :: y :: 0 :: Nil) - case 'or :: x :: y :: Nil => - normalize('if :: x :: 1 :: y :: Nil) - case 'def :: (name :: args) :: body :: expr :: Nil => - normalize('def :: name :: ('lambda :: args :: body :: Nil) :: expr :: Nil) - case 'cond :: ('else :: expr :: Nil) :: rest => - normalize(expr); - case 'cond :: (test :: expr :: Nil) :: rest => - normalize('if :: test :: expr :: ('cond :: rest) :: Nil) - case 'cond :: 'else :: expr :: Nil => - normalize(expr) - case h :: t => - normalize(h) :: asList(normalize(t)) - case _ => - x - } - - def eval(x: Data, env: Environment): Data = { - val prevexp = curexp; - curexp = x; - if (trace) { - for (x <- range(1, indent)) Console.print(" "); - Console.println("===> " + x); - indent += 1; - } - val result = eval1(x, env); - if (trace) { - indent -= 1; - for (x <- range(1, indent)) Console.print(" "); - Console.println("<=== " + result); - } - curexp = prevexp; - result - } - - def eval1(x: Data, env: Environment): Data = x match { - case Symbol(name) => - env lookup name - case 'def :: Symbol(name) :: y :: z :: Nil => - eval(z, env.extendRec(name, (env1 => eval(y, env1)))) - case 'val :: Symbol(name) :: y :: z :: Nil => - eval(z, env.extend(name, eval(y, env))) - case 'lambda :: params :: y :: Nil => - mkLambda(params, y, env) - case 'if :: c :: y :: z :: Nil => - if (asBoolean(eval(c, env))) eval(y, env) else eval(z, env) - case 'quote :: y :: Nil => - y - case y :: z => - apply(eval(y, env), z map (x => eval(x, env))) - case Lambda(_) => x - case y: String => x - case y: Int => x - case y => lispError("illegal term") - } - - def lisp2string(x: Data): String = x match { - case Symbol(name) => name - case Nil => "()" - case y :: ys => - def list2string(xs: List[Data]): String = xs match { - case List() => "" - case y :: ys => " " + lisp2string(y) + list2string(ys) - } - "(" + lisp2string(y) + list2string(ys) + ")" - case _ => if (x.isInstanceOf[String]) "\"" + x + "\""; else x.toString() - } - - def apply(fn: Data, args: List[Data]): Data = fn match { - case Lambda(f) => f(args); - case _ => lispError("application of non-function: " + fn + " to " + args); - } - - def mkLambda(params: Data, expr: Data, env: Environment): Data = { - - def extendEnv(env: Environment, - ps: List[String], args: List[Data]): Environment = - Pair(ps, args) match { - case Pair(List(), List()) => - env - case Pair(p :: ps1, arg :: args1) => - extendEnv(env.extend(p, arg), ps1, args1) - case _ => - lispError("wrong number of arguments") - } - - val ps: List[String] = asList(params) map { - case Symbol(name) => name - case _ => sys.error("illegal parameter list"); - } - - Lambda(args => eval(expr, extendEnv(env, ps, args))) - } - - val globalEnv = EmptyEnvironment - .extend("=", Lambda{ - case List(arg1, arg2) => if(arg1 == arg2) 1 else 0}) - .extend("+", Lambda{ - case List(arg1: Int, arg2: Int) => arg1 + arg2 - case List(arg1: String, arg2: String) => arg1 + arg2}) - .extend("-", Lambda{ - case List(arg1: Int, arg2: Int) => arg1 - arg2}) - .extend("*", Lambda{ - case List(arg1: Int, arg2: Int) => arg1 * arg2}) - .extend("/", Lambda{ - case List(arg1: Int, arg2: Int) => arg1 / arg2}) - .extend("nil", Nil) - .extend("cons", Lambda{ - case List(arg1, arg2) => arg1 :: asList(arg2)}) - .extend("car", Lambda{ - case List(x :: xs) => x}) - .extend("cdr", Lambda{ - case List(x :: xs) => xs}) - .extend("null?", Lambda{ - case List(Nil) => 1 - case _ => 0}); - - def evaluate(x: Data): Data = eval(normalize(x), globalEnv); - def evaluate(s: String): Data = evaluate(string2lisp(s)); - - def string2lisp(s: String): Data = { - val it = new LispTokenizer(s); - def parseExpr(token: String): Data = { - if (token == "(") parseList - else if (token == ")") sys.error("unbalanced parentheses") - //else if (Character.isDigit(token.charAt(0))) - else if (token.charAt(0).isDigit) - token.toInt - else if (token.charAt(0) == '\"' && token.charAt(token.length()-1)=='\"') - token.substring(1,token.length() - 1) - else Symbol(token) - } - def parseList: List[Data] = { - val token = it.next; - if (token == ")") Nil else parseExpr(token) :: parseList - } - parseExpr(it.next) - } -} - -//############################################################################ -// List User - -class LispUser(lisp: Lisp) { - - import lisp._; - - def evaluate(s: String) = lisp2string(lisp.evaluate(s)); - - def run = { - - Console.println(string2lisp("(lambda (x) (+ (* x x) 1))").asInstanceOf[AnyRef]); - Console.println(lisp2string(string2lisp("(lambda (x) (+ (* x x) 1))"))); - Console.println; - - Console.println("( '(1 2 3)) = " + evaluate(" (quote(1 2 3))")); - Console.println("(car '(1 2 3)) = " + evaluate("(car (quote(1 2 3)))")); - Console.println("(cdr '(1 2 3)) = " + evaluate("(cdr (quote(1 2 3)))")); - Console.println("(null? '(2 3)) = " + evaluate("(null? (quote(2 3)))")); - Console.println("(null? '()) = " + evaluate("(null? (quote()))")); - Console.println; - - Console.println("faculty(10) = " + evaluate( - "(def (faculty n) " + - "(if (= n 0) " + - "1 " + - "(* n (faculty (- n 1)))) " + - "(faculty 10))")); - Console.println("faculty(10) = " + evaluate( - "(def (faculty n) " + - "(cond " + - "((= n 0) 1) " + - "(else (* n (faculty (- n 1))))) " + - "(faculty 10))")); - Console.println("foobar = " + evaluate( - "(def (foo n) " + - "(cond " + - "((= n 0) \"a\")" + - "((= n 1) \"b\")" + - "((= (/ n 2) 1) " + - "(cond " + - "((= n 2) \"c\")" + - "(else \"d\")))" + - "(else " + - "(def (bar m) " + - "(cond " + - "((= m 0) \"e\")" + - "((= m 1) \"f\")" + - "(else \"z\"))" + - "(bar (- n 4)))))" + - "(val nil (quote ())" + - "(val v1 (foo 0) " + - "(val v2 (+ (foo 1) (foo 2)) " + - "(val v3 (+ (+ (foo 3) (foo 4)) (foo 5)) " + - "(val v4 (foo 6) " + - "(cons v1 (cons v2 (cons v3 (cons v4 nil))))))))))")); - Console.println; - } -} - -//############################################################################ -// Main - -object Test { - def main(args: Array[String]) { - new LispUser(LispCaseClasses).run; - new LispUser(LispAny).run; - () - } -} - -//############################################################################ |