Relative imports!

This is a breaking change because existing imports in user Wren code
that assume the path is relative to the entrypoint file will now likely
fail.

Also, stack trace output and host API calls that take a module string
now need the resolved module string, not the short name that appears in
the import.

test/language/foreign/unknown_method.wren

@@ -1,3 +1,3 @@
 class Foo {
-  foreign someUnknownMethod // expect runtime error: Could not find foreign method 'someUnknownMethod' for class Foo in module 'main'.
+  foreign someUnknownMethod // expect runtime error: Could not find foreign method 'someUnknownMethod' for class Foo in module 'test/language/foreign/unknown_method'.
 }

test/language/module/change_imported_value/change_imported_value.wren

@@ -1,4 +1,4 @@
-import "module" for Module, Other
+import "./module" for Module, Other
 
 System.print(Module) // expect: before
 

test/language/module/compile_error/compile_error.wren

@@ -1,2 +1,2 @@
 System.print("before") // expect: before
-import "module" for Module // expect runtime error: Could not compile module 'module'.
+import "./module" for Module // expect runtime error: Could not compile module 'test/language/module/compile_error/module'.

test/language/module/cyclic_import/a.wren

@@ -3,7 +3,7 @@ System.print("start a")
 
 var A = "a value"
 System.print("a defined %(A)")
-import "b" for B
+import "./b" for B
 System.print("a imported %(B)")
 
 System.print("end a")

test/language/module/cyclic_import/b.wren

@@ -3,7 +3,7 @@ System.print("start b")
 
 var B = "b value"
 System.print("b defined %(B)")
-import "a" for A
+import "./a" for A
 System.print("b imported %(A)")
 
 System.print("end b")

test/language/module/cyclic_import/cyclic_import.wren

@@ -1,4 +1,4 @@
-import "a"
+import "./a"
 
 // Shared module should only run once:
 // expect: start a

test/language/module/implicitly_imports_core/implicitly_imports_core.wren

@@ -1,4 +1,4 @@
-import "module"
+import "./module"
 // expect: Bool
 // expect: Class
 // expect: Fiber

test/language/module/inside_block/inside_block.wren

@@ -1,7 +1,7 @@
 var Module = "outer"
 
 if (true) {
-  import "module" for Module
+  import "./module" for Module
   // expect: ran module
 
   System.print(Module) // expect: from module

test/language/module/missing_for.wren

@@ -1 +1 @@
-import "module" NoString // expect error
+import "./module" NoString // expect error

test/language/module/module_dir/module_dir.wren

@@ -1,3 +1,3 @@
-import "something" for Index
+import "./something/module" for Index
 
 System.print(Index) // expect: index

test/language/module/multiple_variables/multiple_variables.wren

@@ -1,4 +1,4 @@
-import "module" for Module1, Module2, Module3, Module4, Module5
+import "./module" for Module1, Module2, Module3, Module4, Module5
 
 // Only execute module body once:
 // expect: ran module

test/language/module/name_collision.wren

@@ -1,2 +1,2 @@
 var Collides
-import "module" for Collides // expect error
+import "./module" for Collides // expect error

test/language/module/newlines/newlines.wren

@@ -1,9 +1,9 @@
 import
 
 
-"module"
+"./module"
 
-import "module" for
+import "./module" for
 
 A,
 

test/language/module/no_variable/no_variable.wren

@@ -1,2 +1,2 @@
-import "module"
+import "./module"
 // expect: ran module

test/language/module/relative_import/module_3.wren

@@ -0,0 +1,2 @@
+// nontest
+System.print("module_3")

test/language/module/relative_import/relative_import.wren

@@ -0,0 +1,8 @@
+import "./sub/module"
+import "./sub/././///dir/module"
+// expect: sub/module
+// expect: sub/module_2
+// expect: sub/dir/module
+// expect: sub/dir/module_2
+// expect: sub/module_3
+// expect: module_3

test/language/module/relative_import/sub/dir/module.wren

@@ -0,0 +1,3 @@
+// nontest
+System.print("sub/dir/module")
+import "./module_2"

test/language/module/relative_import/sub/dir/module_2.wren

@@ -0,0 +1,4 @@
+// nontest
+System.print("sub/dir/module_2")
+import "../module_3"
+import "../../module_3"

test/language/module/relative_import/sub/module.wren

@@ -0,0 +1,3 @@
+// nontest
+System.print("sub/module")
+import "./module_2"

test/language/module/relative_import/sub/module_2.wren

@@ -0,0 +1,2 @@
+// nontest
+System.print("sub/module_2")

test/language/module/relative_import/sub/module_3.wren

@@ -0,0 +1,2 @@
+// nontest
+System.print("sub/module_3")

test/language/module/shared_import/a.wren

@@ -1,5 +1,5 @@
 // nontest
 System.print("a")
-import "shared" for Shared
+import "./shared" for Shared
 var A = "a %(Shared)"
 System.print("a done")

test/language/module/shared_import/b.wren

@@ -1,5 +1,5 @@
 // nontest
 System.print("b")
-import "shared" for Shared
+import "./shared" for Shared
 var B = "b %(Shared)"
 System.print("b done")

test/language/module/shared_import/shared_import.wren

@@ -1,5 +1,5 @@
-import "a" for A
-import "b" for B
+import "./a" for A
+import "./b" for B
 
 // Shared module should only run once:
 // expect: a

test/language/module/simple_import/simple_import.wren

@@ -1,4 +1,4 @@
-import "module" for Module
+import "./module" for Module
 // expect: ran module
 
 System.print(Module) // expect: from module

test/language/module/unknown_module.wren

@@ -1 +1 @@
-import "does_not_exist" for DoesNotExist // expect runtime error: Could not load module 'does_not_exist'.
+import "./does_not_exist" for DoesNotExist // expect runtime error: Could not load module 'test/language/module/does_not_exist'.

test/language/module/unknown_variable/unknown_variable.wren

@@ -1,3 +1,3 @@
 // Should execute the module:
 // expect: ran module
-import "module" for DoesNotExist // expect runtime error: Could not find a variable named 'DoesNotExist' in module 'module'.
+import "./module" for DoesNotExist // expect runtime error: Could not find a variable named 'DoesNotExist' in module 'test/language/module/unknown_variable/module'.