1 files changed, 24 insertions, 1 deletions
diff --git a/vish.py b/vish.py
index 608a8b4..8d8f6e1 100755
--- a/vish.py
+++ b/vish.py
@@ -49,7 +49,30 @@ class Instruction():
 
             os.execvp(self.prog, [self.prog] + self.args)
         else:
-            os.waitpid(cpid, 0)
+            _, status = os.waitpid(cpid, 0)
+            return status
+
+
+class AndInstruction(Instruction):
+    def __init__(self, instruction1: Instruction, instruction2: Instruction):
+        self.instruction1 = instruction1
+        self.instruction2 = instruction2
+
+    def execute(self):
+        status = self.instruction1.execute()
+        if os.WIFEXITED(status) and os.WEXITSTATUS(status) == 0:
+            return self.instruction2.execute()
+
+
+class OrInstruction(Instruction):
+    def __init__(self, instruction1: Instruction, instruction2: Instruction):
+        self.instruction1 = instruction1
+        self.instruction2 = instruction2
+
+    def execute(self):
+        status = self.instruction1.execute()
+        if not os.WIFEXITED(status) or not os.WEXITSTATUS(status) == 0:
+            return self.instruction2.execute()
 
 
 class PipelineParser():