Function references are now correctly first class citizens

Resolves #7

9 files changed, 131 insertions, 20 deletions

diff --git a/src/main/com/jantuomi/tunkki/core/parser/ast/CallNode.java b/src/main/com/jantuomi/tunkki/core/parser/ast/CallNode.java
new file mode 100644
index 0000000..6f4e240
--- /dev/null
+++ b/src/main/com/jantuomi/tunkki/core/parser/ast/CallNode.java
@@ -0,0 +1,25 @@
+package com.jantuomi.tunkki.core.parser.ast;
+
+import com.jantuomi.tunkki.core.parser.datatype.CallableDatatype;
+import com.jantuomi.tunkki.core.parser.datatype.Datatype;
+import com.jantuomi.tunkki.core.tokenizer.token.Token;
+import com.jantuomi.tunkki.exception.TunkkiError;
+
+/**
+ * Created by jan on 30.7.2016.
+ */
+public class CallNode extends SymbolNode {
+    public CallNode(Token token) {
+        super(token);
+    }
+
+    @Override
+    public Datatype evaluate() throws TunkkiError {
+        Datatype d = super.evaluate();
+        if (d.getType() == Datatype.Type.Callable) {
+            return ((CallableDatatype) d).call(evaluateParameters());
+        } else {
+            return d;
+        }
+    }
+}
diff --git a/src/main/com/jantuomi/tunkki/core/parser/ast/FunctionDefineNode.java b/src/main/com/jantuomi/tunkki/core/parser/ast/FunctionDefineNode.java
index 7339970..a9b0a7e 100644
--- a/src/main/com/jantuomi/tunkki/core/parser/ast/FunctionDefineNode.java
+++ b/src/main/com/jantuomi/tunkki/core/parser/ast/FunctionDefineNode.java
@@ -1,7 +1,7 @@
 package com.jantuomi.tunkki.core.parser.ast;
 
+import com.jantuomi.tunkki.core.parser.datatype.CallableDatatype;
 import com.jantuomi.tunkki.core.parser.datatype.Datatype;
-import com.jantuomi.tunkki.core.parser.datatype.StringDatatype;
 import com.jantuomi.tunkki.core.runtime.Function;
 import com.jantuomi.tunkki.core.runtime.State;
 import com.jantuomi.tunkki.core.tokenizer.token.Token;
@@ -47,7 +47,9 @@ public class FunctionDefineNode extends VarargOperatorNode {
         function.setName(name);
         State.getInstance().addFunctionToScope(name, function);
 
-        return new StringDatatype("function " + name);
+        CallableDatatype c = new CallableDatatype();
+        c.setData(function);
+        return c;
     }
 
     @Override
diff --git a/src/main/com/jantuomi/tunkki/core/parser/ast/SymbolNode.java b/src/main/com/jantuomi/tunkki/core/parser/ast/SymbolNode.java
index fde44c7..4cfa1df 100644
--- a/src/main/com/jantuomi/tunkki/core/parser/ast/SymbolNode.java
+++ b/src/main/com/jantuomi/tunkki/core/parser/ast/SymbolNode.java
@@ -5,11 +5,9 @@ import com.jantuomi.tunkki.core.runtime.State;
 import com.jantuomi.tunkki.core.tokenizer.token.Token;
 import com.jantuomi.tunkki.exception.ExceptionManager;
 import com.jantuomi.tunkki.exception.TunkkiError;
-import org.apache.commons.lang3.StringUtils;
 
 import java.util.ArrayList;
 import java.util.List;
-import java.util.stream.Collectors;
 
 /**
  * Created by jan on 17.6.2016.
@@ -42,17 +40,17 @@ public class SymbolNode extends ASTNode {
 
     @Override
     public Datatype evaluate() throws TunkkiError {
-        List<Datatype> paramValues = new ArrayList<>();
-        for (ASTNode param : parameters) {
-            Datatype value = param.evaluate();
-            if (value != null) {
-                paramValues.add(value);
-            }
-        }
+
 
         Datatype returnValue;
         try {
-             returnValue = State.getInstance().getSymbolValue(name, paramValues);
+            if (State.getInstance().isFunction(name)) {
+                returnValue = State.getInstance().makeFunctionReference(name);
+            } else {
+                List<Datatype> paramValues = evaluateParameters();
+                returnValue = State.getInstance().evaluateSymbol(name, paramValues);
+            }
+
         }
         /* If a TunkkiError is caught, pass it on with line information */
         catch (TunkkiError ex) {
@@ -63,12 +61,22 @@ public class SymbolNode extends ASTNode {
         if (returnValue != null) {
             return returnValue;
         } else {
-            ExceptionManager.raise(TunkkiError.ExceptionType.UndeclaredSymbolError, getLine(), name,
-                    StringUtils.join(paramValues.stream().map(Datatype::toString).collect(Collectors.toList()), ","));
+            ExceptionManager.raise(TunkkiError.ExceptionType.UndeclaredSymbolError, getLine(), name);
             return null;
         }
     }
 
+    public List<Datatype> evaluateParameters() throws TunkkiError {
+        List<Datatype> paramValues = new ArrayList<>();
+        for (ASTNode param : parameters) {
+            Datatype value = param.evaluate();
+            if (value != null) {
+                paramValues.add(value);
+            }
+        }
+        return paramValues;
+    }
+
     @Override
     List<ASTNode> getChildren() {
         return parameters;
diff --git a/src/main/com/jantuomi/tunkki/core/parser/datatype/CallableDatatype.java b/src/main/com/jantuomi/tunkki/core/parser/datatype/CallableDatatype.java
new file mode 100644
index 0000000..3480b5d
--- /dev/null
+++ b/src/main/com/jantuomi/tunkki/core/parser/datatype/CallableDatatype.java
@@ -0,0 +1,46 @@
+package com.jantuomi.tunkki.core.parser.datatype;
+
+import com.jantuomi.tunkki.core.runtime.Function;
+import com.jantuomi.tunkki.exception.TunkkiError;
+
+import java.util.List;
+
+/**
+ * Created by jan on 30.7.2016.
+ */
+public class CallableDatatype extends Datatype<Function> {
+
+    @Override
+    public Type getType() {
+        return Type.Callable;
+    }
+
+    @Override
+    public String toString() {
+        return String.format("Callable %s", getData().getName());
+    }
+
+    public Datatype call(List<Datatype> params) throws TunkkiError {
+        return getData().evaluate(params);
+    }
+
+    @Override
+    public Datatype<Function> add(Datatype<Function> other) throws TunkkiError {
+        return null;
+    }
+
+    @Override
+    public Datatype<Function> subtract(Datatype<Function> other) throws TunkkiError {
+        return null;
+    }
+
+    @Override
+    public Datatype<Function> multiply(Datatype<Function> other) throws TunkkiError {
+        return null;
+    }
+
+    @Override
+    public Datatype<Function> divide(Datatype<Function> other) throws TunkkiError {
+        return null;
+    }
+}
diff --git a/src/main/com/jantuomi/tunkki/core/parser/datatype/Datatype.java b/src/main/com/jantuomi/tunkki/core/parser/datatype/Datatype.java
index a161f09..887b2f4 100644
--- a/src/main/com/jantuomi/tunkki/core/parser/datatype/Datatype.java
+++ b/src/main/com/jantuomi/tunkki/core/parser/datatype/Datatype.java
@@ -16,7 +16,9 @@ abstract public class Datatype<T> {
         Double,
         String,
         Boolean,
-        Nada, Void
+        Nada,
+        Void,
+        Callable
     }
 
     abstract public Type getType();
diff --git a/src/main/com/jantuomi/tunkki/core/runtime/Scope.java b/src/main/com/jantuomi/tunkki/core/runtime/Scope.java
index 2f7e3a8..0565227 100644
--- a/src/main/com/jantuomi/tunkki/core/runtime/Scope.java
+++ b/src/main/com/jantuomi/tunkki/core/runtime/Scope.java
@@ -1,5 +1,6 @@
 package com.jantuomi.tunkki.core.runtime;
 
+import com.jantuomi.tunkki.core.parser.datatype.CallableDatatype;
 import com.jantuomi.tunkki.core.parser.datatype.Datatype;
 import com.jantuomi.tunkki.exception.TunkkiError;
 
@@ -40,6 +41,21 @@ public class Scope {
         }
     }
 
+    public CallableDatatype getCallable(String symbol) {
+        if (functions.containsKey(symbol)) {
+            Function f = functions.get(symbol);
+            CallableDatatype c = new CallableDatatype();
+            c.setData(f);
+            return c;
+        }
+        else if (parent != null) {
+            return parent.getCallable(symbol);
+        }
+        else {
+            return null;
+        }
+    }
+
     public void setParent(Scope parent) {
         this.parent = parent;
     }
@@ -47,4 +63,8 @@ public class Scope {
     public void addFunction(String symbol, Function func) {
         functions.put(symbol, func);
     }
+
+    public boolean isFunction(String symbol) {
+        return functions.containsKey(symbol);
+    }
 }
diff --git a/src/main/com/jantuomi/tunkki/core/runtime/State.java b/src/main/com/jantuomi/tunkki/core/runtime/State.java
index 1b25712..742e603 100644
--- a/src/main/com/jantuomi/tunkki/core/runtime/State.java
+++ b/src/main/com/jantuomi/tunkki/core/runtime/State.java
@@ -40,15 +40,19 @@ public class State {
         return scopes.peek().resolveSymbol(symbol, Arrays.asList());
     }
 
-    public Datatype getSymbolValue(String symbol) throws TunkkiError {
+    public Datatype evaluateSymbol(String symbol) throws TunkkiError {
         Datatype d = resolveSymbol(symbol);
         return d;
     }
 
-    public Datatype getSymbolValue(String symbol, List<Datatype> parameters) throws TunkkiError {
+    public Datatype evaluateSymbol(String symbol, List<Datatype> parameters) throws TunkkiError {
         return scopes.peek().resolveSymbol(symbol, parameters);
     }
 
+    public boolean isFunction(String symbol) {
+        return scopes.peek().isFunction(symbol);
+    }
+
     public Scope createScope() {
         Scope scope = new Scope();
         if (scopes.size() > 0) {
@@ -75,4 +79,8 @@ public class State {
     public Scope popScope() {
         return scopes.pop();
     }
+
+    public Datatype makeFunctionReference(String name) {
+        return scopes.peek().getCallable(name);
+    }
 }
diff --git a/src/main/com/jantuomi/tunkki/core/tokenizer/token/types/CallToken.java b/src/main/com/jantuomi/tunkki/core/tokenizer/token/types/CallToken.java
index fb925f2..daa55ce 100644
--- a/src/main/com/jantuomi/tunkki/core/tokenizer/token/types/CallToken.java
+++ b/src/main/com/jantuomi/tunkki/core/tokenizer/token/types/CallToken.java
@@ -1,7 +1,7 @@
 package com.jantuomi.tunkki.core.tokenizer.token.types;
 
 import com.jantuomi.tunkki.core.parser.ast.ASTNode;
-import com.jantuomi.tunkki.core.parser.ast.SymbolNode;
+import com.jantuomi.tunkki.core.parser.ast.CallNode;
 import com.jantuomi.tunkki.core.tokenizer.token.Token;
 import com.jantuomi.tunkki.exception.TunkkiError;
 
@@ -18,7 +18,7 @@ public class CallToken extends VarargOperatorToken {
 
     @Override
     public ASTNode generateNode() throws TunkkiError {
-        SymbolNode node = new SymbolNode(this);
+        CallNode node = new CallNode(this);
         node.setName(this.getText());
 
         List<ASTNode> arguments = new ArrayList<>();
diff --git a/src/main/com/jantuomi/tunkki/exception/TunkkiError.java b/src/main/com/jantuomi/tunkki/exception/TunkkiError.java
index 9e0163c..dd48077 100644
--- a/src/main/com/jantuomi/tunkki/exception/TunkkiError.java
+++ b/src/main/com/jantuomi/tunkki/exception/TunkkiError.java
@@ -31,7 +31,7 @@ public class TunkkiError extends Exception {
         errorTexts.put(ExceptionType.TypeError, "Incompatible types %s and %s.");
         errorTexts.put(ExceptionType.ExpectedDifferentTokenError, "Token '%s' expects a different token stack.");
         errorTexts.put(ExceptionType.FunctionArgumentError, "The parameter list given to function %s is either of wrong length or the parameters are of wrong type. Actual: %s");
-        errorTexts.put(ExceptionType.UndeclaredSymbolError, "No symbol %s defined, parameters: [%s].");
+        errorTexts.put(ExceptionType.UndeclaredSymbolError, "No symbol %s defined in the current scope.");
         errorTexts.put(ExceptionType.IncludeError, "File %s could not be included.");
         errorTexts.put(ExceptionType.GeneralError, "%s");
         errorTexts.put(ExceptionType.NadaError, "Can't do operation with a nada value.");