ch15: draft examples

15-more-types/typeddict/books.py

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+# tag::BOOKDICT[]
+from typing import TypedDict, List
+import json
+
+class BookDict(TypedDict):
+    isbn: str
+    title: str
+    authors: List[str]
+    pagecount: int
+# end::BOOKDICT[]
+
+# tag::TOXML[]
+AUTHOR_EL = '<AUTHOR>{}</AUTHOR>'
+
+def to_xml(book: BookDict) -> str:  # <1>
+    elements: List[str] = []  # <2>
+    for key, value in book.items():
+        if isinstance(value, list):  # <3>
+            elements.extend(
+                AUTHOR_EL.format(n) for n in value)  # <4>
+        else:
+            tag = key.upper()
+            elements.append(f'<{tag}>{value}</{tag}>')
+    xml = '\n\t'.join(elements)
+    return f'<BOOK>\n\t{xml}\n</BOOK>'
+# end::TOXML[]
+
+# tag::FROMJSON[]
+def from_json(data: str) -> BookDict:
+    whatever: BookDict = json.loads(data)  # <1>
+    return whatever  # <2>
+# end::FROMJSON[]

15-more-types/typeddict/books_any.py

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+# tag::BOOKDICT[]
+from typing import TypedDict, List
+import json
+
+class BookDict(TypedDict):
+    isbn: str
+    title: str
+    authors: List[str]
+    pagecount: int
+# end::BOOKDICT[]
+
+# tag::TOXML[]
+AUTHOR_EL = '<AUTHOR>{}</AUTHOR>'
+
+def to_xml(book: BookDict) -> str:  # <1>
+    elements: List[str] = []  # <2>
+    for key, value in book.items():
+        if isinstance(value, list):  # <3>
+            elements.extend(AUTHOR_EL.format(n)
+                for n in value)
+        else:
+            tag = key.upper()
+            elements.append(f'<{tag}>{value}</{tag}>')
+    xml = '\n\t'.join(elements)
+    return f'<BOOK>\n\t{xml}\n</BOOK>'
+# end::TOXML[]
+
+# tag::FROMJSON[]
+def from_json(data: str) -> BookDict:
+    whatever = json.loads(data)  # <1>
+    return whatever  # <2>
+# end::FROMJSON[]

15-more-types/typeddict/demo_books.py

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+from books import BookDict
+from typing import TYPE_CHECKING
+
+def demo() -> None:  # <1>
+    book = BookDict(  # <2>
+        isbn='0134757599',
+        title='Refactoring, 2e',
+        authors=['Martin Fowler', 'Kent Beck'],
+        pagecount=478
+    )
+    authors = book['authors'] # <3>
+    if TYPE_CHECKING:  # <4>
+        reveal_type(authors)  # <5>
+    authors = 'Bob'  # <6>
+    book['weight'] = 4.2
+    del book['title']
+
+
+if __name__ == '__main__':
+    demo()

15-more-types/typeddict/demo_not_book.py

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+from books import to_xml, from_json
+from typing import TYPE_CHECKING
+
+def demo() -> None:
+    NOT_BOOK_JSON = """
+        {"title": "Andromeda Strain",
+         "flavor": "pistachio",
+         "authors": true}
+    """
+    not_book = from_json(NOT_BOOK_JSON)  # <1>
+    if TYPE_CHECKING:  # <2>
+        reveal_type(not_book)
+        reveal_type(not_book['authors'])
+
+    print(not_book)  # <3>
+    print(not_book['flavor'])  # <4>
+
+    xml = to_xml(not_book)  # <5>
+    print(xml)  # <6>
+
+
+if __name__ == '__main__':
+    demo()

15-more-types/typeddict/test_books.py

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+import json
+from typing import cast
+
+from books import BookDict, to_xml, from_json
+
+XML_SAMPLE = """
+<BOOK>
+\t<ISBN>0134757599</ISBN>
+\t<TITLE>Refactoring, 2e</TITLE>
+\t<AUTHOR>Martin Fowler</AUTHOR>
+\t<AUTHOR>Kent Beck</AUTHOR>
+\t<PAGECOUNT>478</PAGECOUNT>
+</BOOK>
+""".strip()
+
+
+# using plain dicts
+
+def test_1() -> None:
+    xml = to_xml({
+        'isbn': '0134757599',
+        'title': 'Refactoring, 2e',
+        'authors': ['Martin Fowler', 'Kent Beck'],
+        'pagecount': 478,
+    })
+    assert xml == XML_SAMPLE
+
+def test_2() -> None:
+    xml = to_xml(dict(
+        isbn='0134757599',
+        title='Refactoring, 2e',
+        authors=['Martin Fowler', 'Kent Beck'],
+        pagecount=478))
+    assert xml == XML_SAMPLE
+
+def test_5() -> None:
+    book_data: BookDict = dict(
+        isbn='0134757599',
+        title='Refactoring, 2e',
+        authors=['Martin Fowler', 'Kent Beck'],
+        pagecount=478
+    )
+    xml = to_xml(book_data)
+    assert xml == XML_SAMPLE
+
+def test_6() -> None:
+    book_data = dict(
+        isbn='0134757599',
+        title='Refactoring, 2e',
+        authors=['Martin Fowler', 'Kent Beck'],
+        pagecount=478
+    )
+    xml = to_xml(cast(BookDict, book_data))  # cast needed
+    assert xml == XML_SAMPLE
+
+def test_4() -> None:
+    xml = to_xml(BookDict(
+        isbn='0134757599',
+        title='Refactoring, 2e',
+        authors=['Martin Fowler', 'Kent Beck'],
+        pagecount=478))
+    assert xml == XML_SAMPLE
+
+def test_7() -> None:
+    book_data = BookDict(
+        isbn='0134757599',
+        title='Refactoring, 2e',
+        authors=['Martin Fowler', 'Kent Beck'],
+        pagecount=478
+    )
+    xml = to_xml(book_data)
+    assert xml == XML_SAMPLE
+
+def test_8() -> None:
+    book_data: BookDict = {
+        'isbn': '0134757599',
+        'title': 'Refactoring, 2e',
+        'authors': ['Martin Fowler', 'Kent Beck'],
+        'pagecount': 478,
+    }
+    xml = to_xml(book_data)
+    assert xml == XML_SAMPLE
+
+BOOK_JSON = """
+    {"isbn": "0134757599",
+     "title": "Refactoring, 2e",
+     "authors": ["Martin Fowler", "Kent Beck"],
+     "pagecount": 478}
+"""
+
+def test_load_book_0() -> None:
+    book_data: BookDict = json.loads(BOOK_JSON)  # typed var
+    xml = to_xml(book_data)
+    assert xml == XML_SAMPLE
+
+def test_load_book() -> None:
+    book_data = from_json(BOOK_JSON)
+    xml = to_xml(book_data)
+    assert xml == XML_SAMPLE
+
+
+NOT_BOOK_JSON = """
+    {"isbn": 3.141592653589793
+     "title": [1, 2, 3],
+     "authors": ["Martin Fowler", "Kent Beck"],
+     "flavor": "strawberry"}
+"""
+
+def test_load_not_book() -> None:
+    book_data: BookDict = json.loads(BOOK_JSON)  # typed var
+    xml = to_xml(book_data)
+    assert xml == XML_SAMPLE

15-more-types/typeddict/test_books_check_fails.py

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+from books import BookDict, to_xml
+
+XML_SAMPLE = """
+<BOOK>
+\t<ISBN>0134757599</ISBN>
+\t<TITLE>Refactoring, 2e</TITLE>
+\t<AUTHOR>Martin Fowler</AUTHOR>
+\t<AUTHOR>Kent Beck</AUTHOR>
+\t<PAGECOUNT>478</PAGECOUNT>
+</BOOK>
+""".strip()
+
+def test_3() -> None:
+    xml = to_xml(BookDict(dict([  # Expected keyword arguments, {...}, or dict(...) in TypedDict constructor
+        ('isbn', '0134757599'),
+        ('title', 'Refactoring, 2e'),
+        ('authors', ['Martin Fowler', 'Kent Beck']),
+        ('pagecount', 478),
+    ])))
+    assert xml == XML_SAMPLE