Rework module system

Don't require/allow naming a module, instead require that the importer
names it. Allow importing into the local scope with the name !Local.
Simplify namespacing logic. Updates all tests to reflect these changes.

test/Spec.hs

@@ -532,6 +532,9 @@ modules = testGroup "Test modules"
   , testCase "Lambda expression namespaces" $ do
       res <- liftIO $ evaluateFileResult "./test/lambda-A.tri"
       res @?= Leaf
+  , testCase "Local namespace import chain" $ do
+      res <- liftIO $ evaluateFileResult "./test/local-ns/1.tri"
+      res @?=  Fork (Stem Leaf) (Fork (Stem Leaf) Leaf)
   ]
 
 

test/ascii.tri

@@ -1 +0,0 @@
-t (t (t (t (t t) (t t t)) t) t t) t

test/assignment.tri

@@ -1 +0,0 @@
-x = t (t t) t

test/cycle-1.tri

@@ -1,4 +1,3 @@
-!module Cycle
 
 !import "test/cycle-2.tri" Cycle2
 

test/cycle-2.tri

@@ -1,4 +1,3 @@
-!module Cycle2
 
 !import "test/cycle-1.tri" Cycle1
 

test/lambda-A.tri

@@ -1,2 +1 @@
-!module A
 main = (\x : x) t

test/local-ns/1.tri

@@ -0,0 +1,4 @@
+
+!import "test/local-ns/2.tri" Two
+
+main = Two.x

test/local-ns/2.tri

@@ -0,0 +1,2 @@
+
+!import "test/local-ns/3.tri" !Local

test/local-ns/3.tri

@@ -0,0 +1,2 @@
+
+x = 3

test/modules-1.tri

@@ -1,5 +0,0 @@
-!module Test
-
-!import "lib/base.tri" Lib
-
-main = Lib.not? t

test/modules-2.tri

@@ -1 +0,0 @@
-n = t t t

test/multi-level-A.tri

@@ -1,3 +1,2 @@
-!module A
 !import "./test/multi-level-B.tri" B
 main = B.main

test/multi-level-B.tri

@@ -1,3 +1,2 @@
-!module B
 !import "./test/multi-level-C.tri" C
 main = C.val

test/multi-level-C.tri

@@ -1,2 +1 @@
-!module C
 val = t

test/named-imports/1.tri

@@ -0,0 +1,7 @@
+
+!import "lib/base.tri"
+
+!import "test/named-imports/2.tri"
+!import "test/named-imports/3.tri" ThreeRenamed
+
+main = equal? (equal? Two.x 2) (equal? ThreeRenamed.x 3)

test/named-imports/2.tri

@@ -0,0 +1,2 @@
+
+x = 2

test/named-imports/3.tri

@@ -0,0 +1,2 @@
+
+x = 3

test/namespace-A.tri

@@ -1,3 +1,2 @@
-!module A
 !import "./test/namespace-B.tri" B
 main = B.x

test/namespace-B.tri

@@ -1,2 +1 @@
-!module B
 x = t

test/undefined.tri

@@ -1 +0,0 @@
-namedTerm = undefinedForTesting

test/unresolved-A.tri

@@ -1,2 +1 @@
-!module A
 main = undefinedVar

test/vars-A.tri

@@ -1,4 +1,3 @@
-!module A
 
 !import "./test/vars-B.tri" B
 

test/vars-B.tri

@@ -1,2 +1 @@
-!module B
 y = \x : x

test/vars-C.tri

@@ -1,2 +1 @@
-!module C
 z = t