Support dotted paths in @lookup

Author: mkantor

src/end-to-end.test.ts

@@ -180,7 +180,7 @@ testCases(endToEnd, code => code)('end-to-end tests', [
   ],
   [
     `{@runtime context =>
-      :{context environment lookup}(PATH)
+      :context.environment.lookup(PATH)
     }`,
     output => {
       if (either.isLeft(output)) {

src/language/compiling/semantics/expressions/lookup-expression.ts

@@ -51,7 +51,13 @@ export const readLookupExpression = (
             })
           } else {
             const canonicalizedQuery =
-              typeof query === 'string' ? makeObjectNode({ 0: query }) : query
+              typeof query === 'string'
+                ? makeObjectNode(
+                    Object.fromEntries(
+                      query.split('.').map((key, index) => [index, key]),
+                    ),
+                  )
+                : query
 
             return either.map(
               keyPathFromObjectNode(canonicalizedQuery),