separate core from cli into submodules, add support for boolean and and or operations, make more fields public, fix passing arguments to functions

core/stack.go

@@ -0,0 +1,55 @@
+package core
+
+type Stack[T any] struct {
+	Current Pos
+	Size    Pos
+
+	items []T
+}
+
+func NewStack[T any](size Pos) *Stack[T] {
+	return &Stack[T]{
+		items:   make([]T, size),
+		Size:    size,
+		Current: 0,
+	}
+}
+
+func (s *Stack[T]) Push(items ...T) {
+	for _, item := range items {
+		if s.Current >= s.Size {
+			panic("stack overflow")
+		}
+
+		s.items[s.Current] = item
+		s.Current++
+	}
+}
+
+func (s *Stack[T]) Pop() T {
+	if s.Current <= 0 {
+		panic("stack underflow")
+	}
+
+	s.Current--
+	return s.items[s.Current]
+}
+
+func (s *Stack[T]) Peek() T {
+	if s.Current <= 0 {
+		panic("stack underflow")
+	}
+
+	return s.items[s.Current-1]
+}
+
+// check whether the stack is invalid (stack over-/underflow)
+func (s *Stack[T]) check() {
+	if s.Current >= s.Size {
+		panic("stack underflow")
+	}
+
+	if s.Current < 0 {
+		panic("stack underflow")
+	}
+}