Initial commit

Solutions/9_4/structly/tableformat/formatter.py

@@ -0,0 +1,58 @@
+# tableformat.py
+from abc import ABC, abstractmethod
+
+def print_table(records, fields, formatter):
+    if not isinstance(formatter, TableFormatter):
+        raise RuntimeError('Expected a TableFormatter')
+
+    formatter.headings(fields)
+    for r in records:
+        rowdata = [getattr(r, fieldname) for fieldname in fields]
+        formatter.row(rowdata)
+
+class TableFormatter(ABC):
+    _formats = { }
+
+    @classmethod
+    def __init_subclass__(cls):
+        name = cls.__module__.split('.')[-1]
+        TableFormatter._formats[name] = cls
+
+    @abstractmethod
+    def headings(self, headers):
+        pass
+
+    @abstractmethod
+    def row(self, rowdata):
+        pass
+
+class ColumnFormatMixin:
+    formats = []
+    def row(self, rowdata):
+        rowdata = [ (fmt % item) for fmt, item in zip(self.formats, rowdata)]
+        super().row(rowdata)
+
+class UpperHeadersMixin:
+    def headings(self, headers):
+        super().headings([h.upper() for h in headers])
+
+def create_formatter(name, column_formats=None, upper_headers=False):
+    if name not in TableFormatter._formats:
+        __import__(f'{__package__}.formats.{name}')
+        
+    formatter_cls = TableFormatter._formats.get(name)
+    if not formatter_cls:
+        raise RuntimeError('Unknown format %s' % name)
+
+    if column_formats:
+        class formatter_cls(ColumnFormatMixin, formatter_cls):
+              formats = column_formats
+
+    if upper_headers:
+        class formatter_cls(UpperHeadersMixin, formatter_cls):
+            pass
+
+    return formatter_cls()
+
+
+