Add csv.py

wgmaster/csv.py

@@ -0,0 +1,72 @@
+
+from typing import Iterator, Dict, Any, Optional, Tuple
+import re
+import datetime
+
+
+def parse(filename: str) -> Iterator[Dict[str, Any]]:
+    def parse_line(line_str: str) -> Iterator[str]:
+        w = None
+        s = False
+        for ch in line_str:
+            if w is None:
+                if ch == ';':
+                    yield ''
+                    continue
+                elif ch in (' ', '\t'):
+                    continue
+                w = ch
+                s = ch == '"'
+                continue
+            elif not s and ch in (';', '\n'):
+                yield w.strip()
+                w = None
+                continue
+            elif s and ch == '"':
+                s = False
+            w += ch
+        if w is not None:
+            yield w.strip()
+
+    with open(filename, 'r') as f:
+        header: Optional[Tuple[str]] = None
+        for line in f:
+            if header is None:
+                header = tuple([e.strip() for e in line.strip().split(';')])
+                continue
+
+            obj = {}
+            for i, part in enumerate(parse_line(line)):
+                if part == '':
+                    part = None
+                elif part[0] == '"' and part[-1] == '"':
+                    part = part[1:-1]
+                elif part == 'T':
+                    part = True
+                elif part == 'F':
+                    part = False
+                elif part.isdigit():
+                    part = int(part)
+                elif re.match(r'[0-9]+\.[0-9]+', part):
+                    part = float(part)
+                elif len(part) == 10 and part[4] == '-' and part[7] == '-':
+                    part = datetime.datetime.strptime(part, '%Y-%m-%d').date()
+                else:
+                    raise RuntimeError(part)
+                obj[header[i]] = part
+            yield obj
+
+
+def format_row(*values) -> str:
+    row = ''
+    for val in values:
+        if val is None:
+            pass
+        elif type(val) == str:
+            row += f'"{val}"'
+        elif type(val) == bool:
+            row += 'T' if val else 'F'
+        else:
+            row += str(val)
+        row += ';'
+    return f'{row[:-1]}\n'