Merge pull request #81 from fink-lang/import-explicit-ext

feat(import): support explicit file ext in import URLs and translate .fnk to .js

src/js/do-expression.fnk

@@ -5,6 +5,7 @@
   isReturnStatement, arrowFunctionExpression, callExpression
 } = import '@babel/types'
 {set_props} = import '@fink/js-interop/reflect'
+{undefined} = import '@fink/js-interop/nullish'
 {is_empty} = import '@fink/std-lib/iter'
 {wrap_with_comment_loc} = import '../lang/comments'
 
@@ -13,10 +14,9 @@
 
 get_body = fn path: path.get 'body'
 
-[no_result] = []
 
 # TODO: suport _ or nothing instead of having to use item
-consume_all = fold item: no_result
+consume_all = fold item: undefined
 
 
 simple = fn body, sl=false:
@@ -77,7 +77,7 @@ last_expressions = fn path:
               else:
                 # TODO: don't use mutation
                 items.push last
-            no_result
+            undefined
       items
 
     else:
@@ -174,4 +174,4 @@ transform_do_expr = fn path:
       path.replaceWith
         callExpression arrow, []
 
-  no_result
+  undefined

src/lang/module/import.fnk

@@ -1,8 +1,28 @@
 {callExpression, Import: async_import} = import '@babel/types'
+{ends_with, slice} = import '@fink/std-lib/str'
+
+
+
+resolve_ext = fn import_url:
+  match import_url:
+    ends_with ?, '.fnk':
+      '${slice import_url, 0, -4}.js'
+    else:
+      import_url
+
 
 
 transform_import = fn node, {transform}:
-  right = transform node.right
+  right = match node.right:
+    {type: 'string', exprs: [..., {type: 'string:text'}]}:
+      [...exprs, url] = node.right.exprs
+
+      transform dict:
+        ...node.right
+        exprs: [...exprs, {...url, value: resolve_ext url.value}]
+    else:
+      transform node.right
+
   callExpression
     async_import _
     [right]

src/lang/module/index.fnk

@@ -9,7 +9,8 @@
 
 {wrap_with_comment_loc} = import '../comments'
 {block_statement} = import '../block'
-{transform_import: transform_async_import} = import './import'
+{transform_import: transform_async_import, resolve_ext} = import './import'
+
 
 
 # TODO should larix handle shebang as special expr?
@@ -24,6 +25,7 @@ get_shebang = fn expr:
       [[], expr]
 
 
+
 transform_import = fn node, {transform}:
   [...imports] = match node.left:
     {type: 'ident'}:
@@ -47,7 +49,7 @@ transform_import = fn node, {transform}:
   importDeclaration
     imports
     wrap_with_comment_loc
-      stringLiteral url.value
+      stringLiteral resolve_ext url.value
       node.right.right
 
 
@@ -62,7 +64,7 @@ transform_module = fn node, ctx:
         {op: 'import'}:
           {right: {exprs: [url]}} = expr
           wrap_with_comment_loc
-            importDeclaration [], stringLiteral url.value
+            importDeclaration [], stringLiteral resolve_ext url.value
             expr
 
         {right: {op: 'import'}}:

src/lang/module/index.test.fnk

@@ -11,20 +11,25 @@ describe 'module', fn:
 
         # leading comment
 
-        # imp comment
+        # static imports
         import 'shrub'
+        import '@fink/foo/bar.fnk'
 
-        # imp comment 2
-        foo = import './foo'
+        # default import
+        foo = import './foo.fnk'
 
-        # imp comment 3
-        {bar} = import './spam'
-        {foo: spam} = import './shrub'
+        # import exported values
+        {bar} = import './spam.fnk'
+        {foo: spam} = import './shrub.fnk'
 
-        # expr comment
-        shrub = foo + bar
-        ni = await import spam
+        # dynamic imports with static URL
+        ni = await import './shrub.fnk'
 
+        # dynamic imports with dynamic URLs
+        shrub = foo + bar
+        ni2 = await import shrub
+        ni3 = await import '\${shrub}'
+        ni4 = await import './\${shrub}.fnk'
         # trailing comment
       "
       to_match_snapshot

src/lang/module/index.test.fnk.snap

@@ -3,15 +3,20 @@
 exports[`module handles comments 1`] = `
 "#!/usr/bin/env node
 // leading comment
-// imp comment
+// static imports
 import \\"shrub\\";
-// imp comment 2
-import foo from \\"./foo\\";
-// imp comment 3
-import { bar } from \\"./spam\\";
-import { foo as spam } from \\"./shrub\\";
-// expr comment
+import \\"@fink/foo/bar.js\\";
+// default import
+import foo from \\"./foo.js\\";
+// import exported values
+import { bar } from \\"./spam.js\\";
+import { foo as spam } from \\"./shrub.js\\";
+// dynamic imports with static URL
+export const ni = await import(\`./shrub.js\`);
+// dynamic imports with dynamic URLs
 export const shrub = foo + bar;
-export const ni = await import(spam);
+export const ni2 = await import(shrub);
+export const ni3 = await import(\`\${shrub}\`);
+export const ni4 = await import(\`./\${shrub}.js\`);
 // trailing comment"
 `;