add blog posts: dollcode, python-goto

www/src/data/thoughts/python-goto/goto_label.py

@@ -0,0 +1,46 @@
+import sys, inspect
+ 
+label = lambda lineno: type(
+    'label',
+    (object,),
+    dict(line=lineno)
+)
+ 
+def prepare_labels(fp, scope):
+    with open(fp, 'r') as f:
+        lines = f.readlines()
+ 
+    for lineno, line in enumerate(lines):
+        if line.startswith('#LABEL'):
+            # 1 + 1, first to account for 0 index then to account for comment line
+            scope.__setitem__(line.split(' ')[1].strip(), label(lineno+2)) 
+ 
+_goto = type('goto', (object,), dict(__and__=lambda _, other: (_goto(other.line))))
+ 
+goto = _goto()
+ 
+def _goto(lineno):
+    frame = sys._getframe().f_back.f_back
+    called_from = frame
+ 
+    def hook(frame, event, _):
+        if event == 'line' and frame == called_from:
+            try:
+                frame.f_lineno = lineno
+            except ValueError as e:
+                print("jump failed:", e)
+            while frame:
+                frame.f_trace = None
+                frame = frame.f_back
+            return None
+        return hook
+ 
+    # it doesn't think we actually need to set the hook for each frame
+    # while frame:
+    #     frame.f_trace = hook
+    #     frame = frame.f_back
+ 
+    called_from.f_trace = hook
+    sys.settrace(hook)
+ 
+prepare_labels(inspect.stack()[-1].frame.f_code.co_filename, inspect.stack()[-1].frame.f_globals)