Refactored code structure

src/build/core/Variable.go

@@ -0,0 +1,20 @@
+package core
+
+import (
+	"git.akyoto.dev/cli/q/src/build/cpu"
+	"git.akyoto.dev/cli/q/src/build/expression"
+)
+
+// Variable represents a named register.
+type Variable struct {
+	Value    *expression.Expression
+	Name     string
+	Register cpu.Register
+	Alive    int
+}
+
+// Definitions are single use expressions that don't reside in a register yet.
+type Definition struct {
+	Value *expression.Expression
+	Name  string
+}