init 0.1.0

1 files changed, 33 insertions, 0 deletions

diff --git a/python/astal/binding.py b/python/astal/binding.py
new file mode 100644
index 0000000..0fe1b6c
--- /dev/null
+++ b/python/astal/binding.py
@@ -0,0 +1,33 @@
+import re
+
+
+def kebabify(string):
+    return re.sub(r"([a-z])([A-Z])", r"\1-\2", string).replace("_", "-").lower()
+
+
+class Binding:
+    def __init__(self, emitter, prop=None):
+        self.emitter = emitter
+        self.prop = kebabify(prop) if prop else None
+        self.transform_fn = lambda v: v
+
+    def __str__(self):
+        return f"Binding<{self.emitter}{', ' + self.prop if self.prop else ''}>"
+
+    def as_(self, fn):
+        bind = Binding(self.emitter, self.prop)
+        bind.transform_fn = lambda v: fn(self.transform_fn(v))
+        return bind
+
+    def get(self):
+        if hasattr(self.emitter, "get") and callable(self.emitter.get):
+            return self.transform_fn(self.emitter.get())
+
+        return self.transform_fn(self.emitter[f"get_{self.prop}"]())
+
+    def subscribe(self, callback):
+        if hasattr(self.emitter, "subscribe") and callable(self.emitter.subscribe):
+            return self.emitter.subscribe(lambda _: callback(self.get()))
+
+        i = self.emitter.connect(f"notify::{self.prop}", lambda: callback(self.get()))
+        return lambda: self.emitter.disconnect(i)