From 03b61f43392fd463f2533535143c8f11f05bb351 Mon Sep 17 00:00:00 2001
From: Andre Wagner <WagnerAndre@JohnDeere.com>
Date: Wed, 29 Apr 2026 15:36:22 -0500
Subject: [PATCH] .

---
 CMakeLists.txt          |  3 +++
 src/vm/stack.cc         | 39 +++++++++++++++++++++++++++++++++++++++
 src/vm/stack.hh         | 24 ++++++++++++++++++++++++
 src/vm/tests.cc         | 15 +++++++++++++++
 src/vm/vm_exceptions.hh | 29 +++++++++++++++++++++++++++++
 5 files changed, 110 insertions(+)
 create mode 100644 src/vm/stack.cc
 create mode 100644 src/vm/stack.hh
 create mode 100644 src/vm/vm_exceptions.hh

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 27e1f49..ca26996 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -72,6 +72,9 @@ add_library(lib${PROJECT_NAME} SHARED
         src/vm/instruction.cc
         src/vm/value.cc
         src/vm/value.hh
+        src/vm/stack.cc
+        src/vm/stack.hh
+        src/vm/vm_exceptions.hh
 )
 
 target_compile_options(lib${PROJECT_NAME} PRIVATE ${warnings})
diff --git a/src/vm/stack.cc b/src/vm/stack.cc
new file mode 100644
index 0000000..82a91e0
--- /dev/null
+++ b/src/vm/stack.cc
@@ -0,0 +1,39 @@
+#include "stack.hh"
+
+#include "vm_exceptions.hh"
+
+namespace tyche {
+
+void Stack::push(Value const& value)
+{
+    stack_.push_back(value);
+}
+
+Value Stack::pop()
+{
+    if (stack_.empty())
+        throw VMStackUnderflow();
+
+    Value v = stack_.back();
+    stack_.pop_back();
+    return v;
+}
+
+Value Stack::at(int pos) const
+{
+    try {
+        if (pos >= 0)
+            return stack_.at(pos);
+        else
+            return stack_.at(stack_.size() + pos);
+    } catch (std::out_of_range&) {
+        throw VMStackOutOfRange();
+    }
+}
+
+size_t Stack::size() const
+{
+    return stack_.size();
+}
+
+} // tyche
diff --git a/src/vm/stack.hh b/src/vm/stack.hh
new file mode 100644
index 0000000..8c3ec8d
--- /dev/null
+++ b/src/vm/stack.hh
@@ -0,0 +1,24 @@
+#ifndef TYCHE_STACK_HH
+#define TYCHE_STACK_HH
+
+#include <vector>
+
+#include "value.hh"
+
+namespace tyche {
+
+class Stack {
+public:
+    void push(Value const& value);
+    Value pop();
+
+    [[nodiscard]] Value at(int pos) const;
+    [[nodiscard]] size_t size() const;
+
+private:
+    std::vector<Value> stack_;
+};
+
+} // tyche
+
+#endif //TYCHE_STACK_HH
diff --git a/src/vm/tests.cc b/src/vm/tests.cc
index 40b0bb0..dab978d 100644
--- a/src/vm/tests.cc
+++ b/src/vm/tests.cc
@@ -4,6 +4,7 @@
 #include "../bytecode/bytearray.hh"
 #include "../bytecode/bytecode.hh"
 #include "code.hh"
+#include "stack.hh"
 
 using namespace tyche;
 
@@ -28,6 +29,20 @@ TEST(Code, ImportSingleAndDebug)
     printf("%s\n", code.disassemble().c_str());
 }
 
+TEST(Stack, PushPullGet)
+{
+    Stack stack;
+    stack.push(Value::CreateInteger(10));
+    stack.push(Value::CreateInteger(20));
+    stack.push(Value::CreateInteger(30));
+
+    ASSERT_EQ(stack.size(), 3);
+    ASSERT_EQ(stack.at(0).as_integer(), 10);
+    ASSERT_EQ(stack.at(1).as_integer(), 20);
+    ASSERT_EQ(stack.at(-1).as_integer(), 30);
+    ASSERT_EQ(stack.at(-2).as_integer(), 20);
+}
+
 int main(int argc, char** argv)
 {
     testing::InitGoogleTest(&argc, argv);
diff --git a/src/vm/vm_exceptions.hh b/src/vm/vm_exceptions.hh
new file mode 100644
index 0000000..dc4160f
--- /dev/null
+++ b/src/vm/vm_exceptions.hh
@@ -0,0 +1,29 @@
+#ifndef TYCHE_VM_EXCEPTIONS_HH
+#define TYCHE_VM_EXCEPTIONS_HH
+
+#include <stdexcept>
+#include <string>
+
+namespace tyche {
+
+class VMRuntimeError : public std::runtime_error
+{
+public:
+    explicit VMRuntimeError(std::string const& str) : std::runtime_error(str.c_str()) {}
+};
+
+class VMStackUnderflow : public VMRuntimeError
+{
+public:
+    explicit VMStackUnderflow() : VMRuntimeError("Stack underflow") {}
+};
+
+class VMStackOutOfRange : public VMRuntimeError
+{
+public:
+    explicit VMStackOutOfRange() : VMRuntimeError("Item does not exist in stack") {}
+};
+
+}
+
+#endif //TYCHE_VM_EXCEPTIONS_HH