Data commit

Task/S-expressions/Java/s-expressions-6.java

@@ -0,0 +1,47 @@
+package jfkbits;
+
+
+public class LispParser
+{
+    LispTokenizer tokenizer;
+
+    public LispParser(LispTokenizer input)
+    {
+        tokenizer=input;
+    }
+
+    public class ParseException extends Exception
+    {
+
+    }
+
+    public interface Expr
+    {
+        // abstract parent for Atom and ExprList
+    }
+
+    public Expr parseExpr() throws ParseException
+    {
+        Token token = tokenizer.next();
+        switch(token.type)
+        {
+            case '(': return parseExprList(token);
+            case '"': return new StringAtom(token.text);
+            default: return new Atom(token.text);
+        }
+    }
+
+
+    protected ExprList parseExprList(Token openParen) throws ParseException
+    {
+        ExprList acc = new ExprList();
+        while(tokenizer.peekToken().type != ')')
+        {
+            Expr element = parseExpr();
+            acc.add(element);
+        }
+        Token closeParen = tokenizer.next();
+        return acc;
+    }
+
+}