Add tasks for all the new languages

Task/S-Expressions/Ceylon/s-expressions-1.ceylon

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+module rosetta "1.0.0" {
+	import ceylon.collection "1.2.1";
+}

Task/S-Expressions/Ceylon/s-expressions-2.ceylon

@@ -0,0 +1,156 @@
+import ceylon.collection {
+
+	ArrayList
+}
+
+class Symbol(shared String text) {
+	string => text;
+}
+
+abstract class Node() of Leaf | Branch {}
+class Leaf(shared String|Integer|Float|Symbol data) extends Node() {
+	string => data.string;
+}
+class Branch() extends Node() {
+	shared ArrayList<Node> nodes = ArrayList<Node>();
+	string => nodes.string;
+}
+
+shared void run() {
+	
+	alias Token => String|Character|Integer|Float|Symbol;
+	
+	{Token*} tokenize(String input) {
+				
+		class Mode {
+			shared new neutral {}
+			shared new symbol {}
+			shared new quoted {}
+			shared new integer {}
+			shared new float {}
+			shared new escape {}
+		}
+				
+		value tokens = ArrayList<Token>();
+		variable value mode = Mode.neutral;
+		value currentToken = StringBuilder();
+
+		void completeToken() {
+			value string = currentToken.string;
+			if(mode == Mode.symbol) {
+				tokens.add(Symbol(string));
+			}
+			if(mode == Mode.quoted) {
+				tokens.add(string);
+			}
+			if(mode == Mode.integer) {
+				assert(exists int = parseInteger(string));
+				tokens.add(int);
+			}
+			if(mode == Mode.float) {
+				assert(exists float = parseFloat(string));
+				tokens.add(float);
+			}
+			mode = Mode.neutral;
+			currentToken.clear();
+		}
+
+		for(char in input) {
+			switch(char)
+			case('(' | ')') {
+				if(mode != Mode.quoted) {
+					completeToken();
+					tokens.add(char);
+				} else {
+					currentToken.appendCharacter(char);
+				}
+			}
+			case('\"') {
+				if(mode == Mode.escape) {
+					currentToken.appendCharacter(char);
+					mode = Mode.quoted;
+				} else if(mode != Mode.quoted) {
+					mode = Mode.quoted;
+				} else if(mode == Mode.quoted) {
+					completeToken();
+				}
+			}
+			case('\\') {
+				if(mode == Mode.quoted) {
+					mode = Mode.escape;
+				} else {
+					currentToken.appendCharacter(char);
+				}
+			}
+			case(' ' | '\n' | '\r') {
+				if(mode != Mode.quoted) {
+					completeToken();
+				} else {
+					currentToken.append(" ");
+				}
+			}
+			else {
+				if(mode == Mode.neutral) {
+					if(char.digit) {
+						mode = Mode.integer;
+					} else {
+						mode = Mode.symbol;
+					}
+				}
+				if(mode == Mode.integer && (char == '.' || char == ',')) {
+					mode = Mode.float;
+				}
+				currentToken.appendCharacter(char);
+			}
+		}
+		completeToken();
+		return tokens;
+	}
+	
+	Node readFromTokens(ArrayList<Token> tokens) {
+		if(exists first = tokens.accept()) {
+			if(first == '(') {
+				value branch = Branch();
+				while(!tokens.empty) {
+					if(exists token = tokens.first) {
+						if(token == ')') {
+							tokens.accept();
+							break;
+						} else {
+							branch.nodes.add(readFromTokens(tokens));
+						}
+					}
+				}
+				return branch;
+			} else {
+				if(is String|Integer|Float|Symbol first) {
+					return Leaf(first);
+				} else {
+					throw Exception("unexpected token ``first``");
+				}
+			}
+		} else {
+			return Branch();
+		}
+	}
+	
+	void prettyPrint(Node node, Integer indentation = 0) {
+		
+		void paddedPrint(String s) => print(" ".repeat(indentation) + s);
+		
+		if(is Leaf node) {
+			paddedPrint(node.string);
+		} else {
+			paddedPrint("(");
+			for(n in node.nodes) {
+				prettyPrint(n, indentation + 2);
+			}
+			paddedPrint(")");
+		}
+	}
+
+	value tokens = tokenize("""((data "quoted data" 123 4.5)
+                                (data (!@# (4.5) "(more" "data)")))""");
+	value tree = readFromTokens(ArrayList {*tokens});
+	prettyPrint(tree);
+}