125 lines
4.1 KiB
ReStructuredText
125 lines
4.1 KiB
ReStructuredText
======================================
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Create it's own option
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======================================
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Generic regexp option: :class:`RegexpOption`
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====================================================
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Use `RegexpOption` to create custom option is very simple.
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You just have to create an object that inherits from `RegexpOption` and that has the following class attributes:
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- __slots__: with new data members (the values should always be `tuple()`)
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- _type = with a name
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- _display_name: with the display name (for example in error message)
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- _regexp: with a compiled regexp
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Here an example to an option that only accept string with on lowercase ASCII vowel characters:
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.. literalinclude:: src/own_option.py
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:lines: 3-11
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:linenos:
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Let's try our object:
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>>> VowelOption('vowel', 'Vowel', 'aae')
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<VowelOption object at 0x7feb2779c050>
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>>> try:
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... VowelOption('vowel', 'Vowel', 'oooups')
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... except ValueError as err:
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... print(err)
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...
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"oooups" is an invalid string with vowel for "Vowel"
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Create you own option
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=================================
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An option always inherits from `Option` object. This object has the following class attributes:
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- __slots__: with new data members (the values should always be `tuple()`)
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- _type = with a name
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- _display_name: with the display name (for example in error message)
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Here an example to an lipogram option:
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.. literalinclude:: src/own_option2.py
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:lines: 3-15
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:linenos:
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First of all we want to add a custom parameter to ask the minimum length (`min_len`) of the value:
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.. literalinclude:: src/own_option2.py
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:lines: 16-20
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:linenos:
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We have a first validation method. In this method, we verify that the value is a string and that there is no "e" on it:
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.. literalinclude:: src/own_option2.py
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:lines: 22-29
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:linenos:
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Even if user set warnings_only attribute, this method will raise.
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Finally we add a method to valid the value length. If `warnings_only` is set to True, a warning will be emit:
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.. literalinclude:: src/own_option2.py
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:lines: 31-43
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:linenos:
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Let's test it:
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1. the character "e" is in the value:
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>>> try:
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... LipogramOption('lipo',
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... 'Lipogram',
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... 'I just want to add a quality string that has no bad characters')
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... except ValueError as err:
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... print(err)
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...
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"I just want to add a quality string that has no bad characters" is an invalid lipogram for "Lipogram", Perec wrote a book without any "e", you could not do it in a simple sentence?
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2. the character "e" is in the value and warnings_only is set to True:
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>>> try:
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... LipogramOption('lipo',
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... 'Lipogram',
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... 'I just want to add a quality string that has no bad characters',
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... warnings_only=True)
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... except ValueError as err:
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... print(err)
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...
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"I just want to add a quality string that has no bad characters" is an invalid lipogram for "Lipogram", Perec wrote a book without any "e", you could not do it in a simple sentence?
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3. the value is too short
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>>> try:
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... LipogramOption('lipo',
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... 'Lipogram',
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... 'I just want to add a quality string that has no bad symbols')
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... except ValueError as err:
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... print(err)
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...
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"I just want to add a quality string that has no bad symbols" is an invalid lipogram for "Lipogram", you must have at least 100 characters in the sentence
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4. the value is too short and warnings_only is set to True:
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>>> warnings.simplefilter('always', ValueWarning)
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>>> with warnings.catch_warnings(record=True) as warn:
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... LipogramOption('lipo',
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... 'Lipogram',
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... 'I just want to add a quality string that has no bad symbols',
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... warnings_only=True)
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... if warn:
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... print(warn[0].message)
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...
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attention, "I just want to add a quality string that has no bad symbols" could be an invalid lipogram for "Lipogram", it would be better to have at least 100 characters in the sentence
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5. set minimum length to 50 characters, the value is valid:
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>>> LipogramOption('lipo',
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... 'Lipogram',
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... 'I just want to add a quality string that has no bad symbols',
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... min_len=50)
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