Refactoring

added a Result type

separated presentation from logic

moved utility code into separate modules

1 files changed, 60 insertions, 0 deletions

diff --git a/pomu/util/result.py b/pomu/util/result.py
new file mode 100644
index 0000000..1d5092f
--- /dev/null
+++ b/pomu/util/result.py
@@ -0,0 +1,60 @@
+"""Result type module"""
+
+class ResultException(Exception):
+    pass
+
+class Result():
+    """Result = Err E | Ok V"""
+
+    def __init__(self, is_val):
+        self._is_val = is_val
+
+    @classmethod
+    def Ok(cls, val):
+        res = cls(True)
+        res._val = val
+        return res
+
+    @classmethod
+    def Err(cls, val):
+        res = cls(False)
+        res._val = val
+        return res
+
+    def is_ok(self):
+        return self._is_val
+
+    def is_err(self):
+        return not self._is_val
+
+    def ok(self):
+        return self._val if self._is_val else None
+
+    def err(self):
+        return self._val if not self._is_val else None
+
+    def map(self, f):
+        return Result.Ok(f(self.ok())) if self._is_val else Result.Err(self.err())
+
+    def map_err(self, f):
+        return Result.Err(f(self.err())) if not self._is_val else Result.Ok(self.ok())
+
+    def unwrap(self):
+        return self.expect(self.err())
+
+    def expect(self, msg='Error'):
+        if self._is_val:
+            return self._val
+        raise ResultException(msg + ': ' + self._val)
+
+    def unwrap_err(self):
+        return self.expect_err(self.ok())
+
+    def expect_err(self, msg='Error'):
+        if not self._is_val:
+            return self._val
+        raise ResultException(msg + ': ' + self._val)
+
+    def __iter__(self):
+        if self._is_val:
+            yield self._val