Complex import sample and support for import dependency cycles.

examples/complex/a.pork

@@ -0,0 +1,3 @@
+export func a() {
+  println("A")
+}

examples/complex/b.pork

@@ -0,0 +1,6 @@
+import "c.pork"
+
+export func b() {
+  c()
+  println("B")
+}

examples/complex/c.pork

@@ -0,0 +1,6 @@
+import "a.pork"
+
+export func c() {
+  a()
+  println("C")
+}

examples/complex/d.pork

@@ -0,0 +1,6 @@
+import "b.pork"
+
+export func d() {
+  b()
+  println("D")
+}

examples/complex/main.pork

@@ -0,0 +1,5 @@
+import "d.pork"
+
+export func main() {
+  d()
+}

src/main/kotlin/gay/pizza/pork/eval/EvaluationContext.kt

@@ -8,12 +8,18 @@ class EvaluationContext(
   val evaluationContextProvider: EvaluationContextProvider,
   rootScope: Scope
 ) {
+  private var isAlreadySetup = false
+
   val internalScope = rootScope.fork()
   val externalScope = rootScope.fork()
 
   private val evaluationVisitor = EvaluationVisitor(internalScope)
 
   fun setup() {
+    if (isAlreadySetup) {
+      return
+    }
+    isAlreadySetup = true
     val imports = compilationUnit.declarations.filterIsInstance<ImportDeclaration>()
     for (import in imports) {
       val evaluationContext = evaluationContextProvider.provideEvaluationContext(import.path.text)

src/main/kotlin/gay/pizza/pork/eval/EvaluationVisitor.kt

@@ -3,7 +3,7 @@ package gay.pizza.pork.eval
 import gay.pizza.pork.ast.NodeVisitor
 import gay.pizza.pork.ast.nodes.*
 
-class EvaluationVisitor(val root: Scope) : NodeVisitor<Any> {
+class EvaluationVisitor(root: Scope) : NodeVisitor<Any> {
   private var currentScope: Scope = root
 
   override fun visitIntLiteral(node: IntLiteral): Any = node.value

src/main/kotlin/gay/pizza/pork/eval/ImportLoader.kt

@@ -1,7 +0,0 @@
-package gay.pizza.pork.eval
-
-import gay.pizza.pork.ast.nodes.CompilationUnit
-
-interface ImportLoader {
-  fun load(path: String): CompilationUnit
-}

src/main/kotlin/gay/pizza/pork/eval/NullImportLoader.kt

@@ -1,9 +0,0 @@
-package gay.pizza.pork.eval
-
-import gay.pizza.pork.ast.nodes.CompilationUnit
-
-object NullImportLoader : ImportLoader {
-  override fun load(path: String): CompilationUnit {
-    throw RuntimeException("NullImportLoader cannot import compilation units.")
-  }
-}