From 45a2b88d584fc8bdee1fbaf0def1d9b55ba26eff Mon Sep 17 00:00:00 2001
From: Jan Tuomi <jans.tuomi@gmail.com>
Date: Tue, 21 Jun 2016 20:07:32 +0300
Subject: Added scopes, variables and functions

---
 main/core/runtime/Function.java | 41 +++++++++++++++++++++++++++++++++++
 main/core/runtime/Scope.java    | 48 +++++++++++++++++++++++++++++++++++++++++
 main/core/runtime/State.java    | 47 +++++++++++++++++++++++++++++-----------
 3 files changed, 124 insertions(+), 12 deletions(-)
 create mode 100644 main/core/runtime/Function.java
 create mode 100644 main/core/runtime/Scope.java

(limited to 'main/core/runtime')

diff --git a/main/core/runtime/Function.java b/main/core/runtime/Function.java
new file mode 100644
index 0000000..cf6422f
--- /dev/null
+++ b/main/core/runtime/Function.java
@@ -0,0 +1,41 @@
+package com.jantuomi.interpreter.main.core.runtime;
+
+import com.jantuomi.interpreter.main.core.parser.ast.FunctionBodyNode;
+import com.jantuomi.interpreter.main.core.parser.datatype.DataContainer;
+
+import java.util.List;
+
+/**
+ * Created by jan on 20.6.2016.
+ */
+public class Function {
+
+    private List<String> argumentNames;
+
+    private FunctionBodyNode body;
+
+    public Function(List<String> argumentNames, FunctionBodyNode body) {
+        this.argumentNames = argumentNames;
+        this.body = body;
+    }
+
+    public DataContainer evaluate(List<DataContainer> params) {
+        State.getInstance().createScope();
+
+        if (params.size() != argumentNames.size()) {
+            return null;
+        }
+
+        for (int i = 0; i < argumentNames.size(); i++) {
+            State.getInstance().addSymbolToScope(argumentNames.get(i));
+            State.getInstance().setSymbolValueToScope(argumentNames.get(i), params.get(i));
+        }
+
+        DataContainer returnValue = body.evaluate();
+
+        State.getInstance().popScope();
+
+        return returnValue;
+    }
+
+}
diff --git a/main/core/runtime/Scope.java b/main/core/runtime/Scope.java
new file mode 100644
index 0000000..a45cdd7
--- /dev/null
+++ b/main/core/runtime/Scope.java
@@ -0,0 +1,48 @@
+package com.jantuomi.interpreter.main.core.runtime;
+
+import com.jantuomi.interpreter.main.core.parser.datatype.DataContainer;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * Created by jan on 20.6.2016.
+ */
+public class Scope {
+    private Scope parent = null;
+
+    private Map<String, DataContainer> variables = new HashMap<>();
+    private Map<String, Function> functions = new HashMap<>();
+
+    public void addVariable(String symbol) {
+        variables.put(symbol, null);
+    }
+
+    public void setVariableValue(String symbol, DataContainer value) {
+        variables.replace(symbol, value);
+    }
+
+    public DataContainer resolveSymbol(String symbol, List<DataContainer> params) {
+        if (functions.containsKey(symbol)) {
+            return functions.get(symbol).evaluate(params);
+        }
+        if (variables.containsKey(symbol)) {
+            return variables.get(symbol);
+        }
+        else if (parent != null) {
+            return parent.resolveSymbol(symbol, params);
+        }
+        else {
+            return null;
+        }
+    }
+
+    public void setParent(Scope parent) {
+        this.parent = parent;
+    }
+
+    public void addFunction(String symbol, Function func) {
+        functions.put(symbol, func);
+    }
+}
diff --git a/main/core/runtime/State.java b/main/core/runtime/State.java
index 7d1a2fa..72a268b 100644
--- a/main/core/runtime/State.java
+++ b/main/core/runtime/State.java
@@ -1,11 +1,10 @@
 package com.jantuomi.interpreter.main.core.runtime;
 
-import com.jantuomi.interpreter.main.core.parser.ast.ASTNode;
 import com.jantuomi.interpreter.main.core.parser.datatype.DataContainer;
 
-import java.util.HashMap;
+import java.util.Arrays;
 import java.util.List;
-import java.util.Map;
+import java.util.Stack;
 
 /**
  * Created by jan on 11.6.2016.
@@ -17,26 +16,50 @@ public class State {
         return instance;
     }
 
-    private Map<String, DataContainer> variables = new HashMap<>();
+    private Stack<Scope> scopes = new Stack<>();
 
     private State() {
+        /* Push global scope onto the stack */
+        scopes.push(new Scope());
+    }
 
+    private DataContainer resolveSymbol(String symbol) {
+        return scopes.peek().resolveSymbol(symbol, Arrays.asList());
     }
 
     public DataContainer getSymbolValue(String symbol) {
-        if (variables.keySet().contains(symbol)) {
-            return variables.get(symbol);
+        DataContainer d = resolveSymbol(symbol);
+        return d;
+    }
+
+    public DataContainer getSymbolValue(String symbol, List<DataContainer> parameters) {
+        return scopes.peek().resolveSymbol(symbol, parameters);
+    }
+
+    public Scope createScope() {
+        Scope scope = new Scope();
+        if (scopes.size() > 0) {
+            scope.setParent(scopes.peek());
         } else {
-            return null;
+            scope.setParent(null);
         }
+        scopes.push(scope);
+        return scope;
+    }
+
+    public void addSymbolToScope(String symbol) {
+        scopes.peek().addVariable(symbol);
+    }
+
+    public void addFunctionToScope(String symbol, Function func) {
+        scopes.peek().addFunction(symbol, func);
     }
 
-    public DataContainer getSymbolValue(String symbol, List<ASTNode> parameters) {
-        // TODO
-        return null;
+    public void setSymbolValueToScope(String symbol, DataContainer value) {
+        scopes.peek().setVariableValue(symbol, value);
     }
 
-    public void setSymbolValue(String symbol, DataContainer value) {
-        variables.put(symbol, value);
+    public Scope popScope() {
+        return scopes.pop();
     }
 }
-- 
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