Emitting prototypes for all declared functions.

Nodes.cpp

@@ -194,15 +194,20 @@ void FunArg::emit(std::ostream &stream, int indent) {
 }
 
 void Function::emit(std::ostream &stream, int indent) {
+    emitSignature(stream, indent);
+    stream << " {\n";
+    body->emit(stream, indent + 1);
+    stream << "}\n\n";
+}
+
+void Function::emitSignature(std::ostream &stream, int indent) {
     emitIndent(stream, indent);
 
     stream << type << ' ';
     name->emit(stream);
     stream << "(";
     args->emit(stream);
-    stream << ") {\n";
-    body->emit(stream, indent + 1);
-    stream << "}\n\n";
+    stream << ")";
 }
 
 void Main::emit(std::ostream &stream, int indent) {
@@ -217,6 +222,13 @@ void Program::emit(std::ostream &stream, int indent) {
     stream << "#include <iostream>\n";
     stream << "#include <cstdlib>\n\n";
 
+    for (Function *f: functions) {
+        f->emitSignature(stream);
+        stream << ";\n";
+    }
+
+    stream << "\n";
+
     for (Function *f: functions) {
         f->emit(stream);
     }

Nodes.hpp

@@ -310,6 +310,7 @@ public:
     virtual ~Function() {}
 
     virtual void emit(std::ostream &stream, int indent = 0);
+    void emitSignature(std::ostream &stream, int indent = 0);
 
 private:
     Pointer<Id> name;