2 files changed, 110 insertions, 0 deletions
diff --git a/source/base/definition.d b/source/base/definition.d
new file mode 100644
index 0000000..cf64f3e
--- /dev/null
+++ b/source/base/definition.d
@@ -0,0 +1,62 @@
+module base.definition;
+
+import std.string;
+import std.variant;
+import std.typecons;
+
+import std.container : DList;
+
+import base.stack;
+
+alias Words = Stack!Token[string];
+
+Nullable!(DList!Token) definition;
+Words                  words;
+
+void start() {
+	definition = DList!Token();
+}
+
+void end() {
+	string wordToBeDefined;
+
+	definition.front.visit!(
+		(int    value) => wordToBeDefined = "",
+		(bool   value) => wordToBeDefined = "",
+		(string name ) => wordToBeDefined = name
+	);
+
+	if ( wordToBeDefined == "" ) {
+		throw new Exception("words may not be numeric or boolean");
+	}
+
+	definition.removeFront;
+	words[wordToBeDefined] = Stack!Token(definition[]);
+	definition.nullify;
+}
+
+bool handle(Token token) {
+	if ( definition.isNull ) {
+		return false;
+	} else {
+		if ( token.type == typeid(string) ) {
+			if ( *token.peek!string == ";" ) {
+				end;
+			} else {
+				definition.insertBack(token);
+			}
+		} else {
+			definition.insertBack(token);
+		}
+
+		return true;
+	}
+}
+
+Stack!Token get(string word) {
+	if ( word in words ) {
+		return words[word].dup;
+	} else {
+		return Stack!Token(Token(word));
+	}
+}
diff --git a/source/base/stack.d b/source/base/stack.d
new file mode 100644
index 0000000..253bac0
--- /dev/null
+++ b/source/base/stack.d
@@ -0,0 +1,48 @@
+module base.stack;
+
+import std.conv;
+import std.string;
+import std.variant;
+import std.container : SList;
+
+import definition = base.definition;
+
+alias Token = Algebraic!(int, bool, string);
+alias Stack = SList;
+
+Stack!Token stack;
+
+Token toToken(string value) {
+	if ( value.isNumeric ) {
+		return Token(parse!int(value));
+	} else {
+		return Token(value);
+	}
+}
+
+Token top(ref Stack!Token stack) {
+	if ( stack.empty ) {
+		throw new Exception("stack is empty");
+	} else {
+		return stack.front;
+	}
+}
+
+Token pop(ref Stack!Token stack) {
+	Token token = stack.top;
+	stack.removeFront;
+	return token;
+}
+
+void push(ref Stack!Token stack, Token token) {
+	if ( !definition.handle(token) ) {
+		stack.insertFront(token);
+	}
+}
+
+template push(T)
+if ( is(T == int) || is(T == bool) || is (T == string) ) {
+	void push(ref Stack!Token stack, T value) {
+		stack.push(Token(value));
+	}
+}