feat: implement negation (#341)

Author: jeff-hykin

mod.test.ts

@@ -2323,6 +2323,15 @@ Deno.test("windows cmd file", { ignore: Deno.build.os !== "windows" }, async ()
   });
 });
 
+Deno.test("negation chaining", async () => {
+  await assertEquals(await $`! false && echo 1`.text(), "1");
+  await assertRejects(
+    () => $`! echo hello && ! echo 1`.text(),
+    Error,
+    "Exited with code: 1",
+  );
+});
+
 function ensurePromiseNotResolved(promise: Promise<unknown>) {
   return new Promise<void>((resolve, reject) => {
     promise.then(() => reject(new Error("Promise was resolved")));

src/shell.ts

@@ -586,10 +586,16 @@ function executeSequence(sequence: Sequence, context: Context): Promise<ExecuteR
 }
 
 function executePipeline(pipeline: Pipeline, context: Context): Promise<ExecuteResult> {
+  const output = executePipelineInner(pipeline.inner, context);
   if (pipeline.negated) {
-    throw new Error("Negated pipelines are not implemented.");
+    return Promise.resolve(output).then((result) => {
+      return {
+        ...result,
+        code: result.code === 0 ? 1 : 0,
+      };
+    });
   }
-  return executePipelineInner(pipeline.inner, context);
+  return output;
 }
 
 async function executeBooleanList(list: BooleanList, context: Context): Promise<ExecuteResult> {