Typing-sig April 2021

typing-sig@python.org

22 participants
13 discussions

Re: 回复：[Typing-sig] Re: 回复：[Typing-sig] Re: More forgiving TypedDict?
by Paul Bryan 07 Apr '21

07 Apr '21

+1 to the idea in principle. It can easily be implemented in a dynamic type checker (my area of interest). Some thought will need to be put into how subclassing should work (similar to the current "total" inheritance situation). Paul P.S. I was tempted to suggest some kind of wildcard key or key pattern matching, but I think that deviates from the relatively simple solution you're suggesting. On Wed, 2021-04-07 at 15:09 +0800, NGC4039 wrote: > For a third-party type checker, only the type of the value > corresponding to the defined key needs to be checked, and the value > type of the undefined key only needs to be deduced to non-existent > (just like https://www.python.org/dev/peps/pep-0655/) or Any type. > > > > ------------------ 原始邮件 ------------------ > 发件人: "Paul Bryan" <pbryan(a)anode.ca>; > 发送时间: 2021年4月7日(星期三) 下午3:03 > 收件人: "typing-sig"<typing-sig(a)python.org>; > > 主题: [Typing-sig] Re: 回复：[Typing-sig] Re: More forgiving TypedDict? > > Sorry, I didn't read the second part of your answer (constraining > types for certain keys) before I replied. > > Q3. Are you expecting that a static type checker will constrain such > types? > > Paul > > On Tue, 2021-04-06 at 23:59 -0700, Paul Bryan wrote: > > Ah, non-str values in WSGI environ. Thanks. So, rephrasing my > > second question: > > > > Q2: Since environ keys must be str, and as you don't want to > > validate the keys, what is the value of using TypedDict[...] over, > > say, dict[str, Any]? > > > > Paul > > > > On Wed, 2021-04-07 at 14:49 +0800, NGC4039 wrote: > > > I think the value type of the undefined key should be Any. > > > > > > The significance of the TypedDict that allows undefined keys is > > > that we can constrain the types of some keys and values. > > > > > > ------------------ 原始邮件 ------------------ > > > 发件人: "Paul Bryan" <pbryan(a)anode.ca>; > > > 发送时间: 2021年4月7日(星期三) 下午2:42 > > > 收件人: "NGC4039"<me(a)abersheeran.com>;"typing-sig"<typing- > > > sig(a)python.org>; > > > > > > 主题: [Typing-sig] Re: More forgiving TypedDict? > > > > > > As you point out, TypedDict was proposed to explicitly reject an > > > invalid key. > > > > > > Q1: In your view, would allowing undefined keys simply allow any > > > undefined key to be considered valid, regardless of value? > > > > > > Q2: Since environ keys and values must be str, and as you don't > > > want to validate the keys, what is the value of using > > > TypedDict[...] over, say, dict[str, str]? > > > > > > Paul > > > > > > On Wed, 2021-04-07 at 14:00 +0800, Aber wrote: > > > Hey, everyone. > > > > > > When writing a more static WSGI definition based on PEP3333, I > > > discovered such a problem. TypedDict cannot describe the HTTP_* > > > keys in the WSGI specification. I know that one of the original > > > intentions of TypedDict is to prevent typing the wrong keys. But > > > can we add an option (for example: allow_undefined=True) to allow > > > this actual problem? > > > > > > Now the definition I wrote is here > > > https://gist.github.com/abersheeran/f3723029387fe7f6584c6b157b90a > > > 50a > > > In order to allow undefined key values to be used, such as > > > `HTTP_HOST`, perhaps it can be used like the following (there is > > > currently no specification, this is just the solution I > > > envisioned). > > > > > > ```python > > > class Environ(CGIRequiredDefined, CGIOptionalDefined, > > > WSGIDefined, allow_undefined=True): > > > """ > > > WSGI Environ > > > """ > > > ``` > > > > > > Or is there a solution that I don’t know? > > > > > > --- > > > Aber > > > > > > _______________________________________________ > > > Typing-sig mailing list -- typing-sig(a)python.org > > > To unsubscribe send an email to typing-sig-leave(a)python.org > > > https://mail.python.org/mailman3/lists/typing-sig.python.org/ > > > Member address: pbryan(a)anode.ca > > > > > > > _______________________________________________ > > Typing-sig mailing list -- typing-sig(a)python.org > > To unsubscribe send an email to typing-sig-leave(a)python.org > > https://mail.python.org/mailman3/lists/typing-sig.python.org/ > > Member address: pbryan(a)anode.ca > >

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Re: 回复：[Typing-sig] Re: More forgiving TypedDict?
by Paul Bryan 07 Apr '21

07 Apr '21

Ah, non-str values in WSGI environ. Thanks. So, rephrasing my second question: Q2: Since environ keys must be str, and as you don't want to validate the keys, what is the value of using TypedDict[...] over, say, dict[str, Any]? Paul On Wed, 2021-04-07 at 14:49 +0800, NGC4039 wrote: > I think the value type of the undefined key should be Any. > > The significance of the TypedDict that allows undefined keys is that > we can constrain the types of some keys and values. > > ------------------ 原始邮件 ------------------ > 发件人: "Paul Bryan" <pbryan(a)anode.ca>; > 发送时间: 2021年4月7日(星期三) 下午2:42 > 收件人: "NGC4039"<me(a)abersheeran.com>;"typing-sig"<typing- > sig(a)python.org>; > > 主题: [Typing-sig] Re: More forgiving TypedDict? > > As you point out, TypedDict was proposed to explicitly reject an > invalid key. > > Q1: In your view, would allowing undefined keys simply allow any > undefined key to be considered valid, regardless of value? > > Q2: Since environ keys and values must be str, and as you don't want > to validate the keys, what is the value of using TypedDict[...] over, > say, dict[str, str]? > > Paul > > On Wed, 2021-04-07 at 14:00 +0800, Aber wrote: > Hey, everyone. > > When writing a more static WSGI definition based on PEP3333, I > discovered such a problem. TypedDict cannot describe the HTTP_* keys > in the WSGI specification. I know that one of the original intentions > of TypedDict is to prevent typing the wrong keys. But can we add an > option (for example: allow_undefined=True) to allow this actual > problem? > > Now the definition I wrote is here > https://gist.github.com/abersheeran/f3723029387fe7f6584c6b157b90a50a > In order to allow undefined key values to be used, such as > `HTTP_HOST`, perhaps it can be used like the following (there is > currently no specification, this is just the solution I envisioned). > > ```python > class Environ(CGIRequiredDefined, CGIOptionalDefined, WSGIDefined, > allow_undefined=True): > """ > WSGI Environ > """ > ``` > > Or is there a solution that I don’t know? > > --- > Aber > > _______________________________________________ > Typing-sig mailing list -- typing-sig(a)python.org > To unsubscribe send an email to typing-sig-leave(a)python.org > https://mail.python.org/mailman3/lists/typing-sig.python.org/ > Member address: pbryan(a)anode.ca >

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More forgiving TypedDict?
by Aber 07 Apr '21

07 Apr '21

Hey, everyone. When writing a more static WSGI definition based on PEP3333, I discovered such a problem. TypedDict cannot describe the HTTP_* keys in the WSGI specification. I know that one of the original intentions of TypedDict is to prevent typing the wrong keys. But can we add an option (for example: allow_undefined=True) to allow this actual problem? Now the definition I wrote is here https://gist.github.com/abersheeran/f3723029387fe7f6584c6b157b90a… In order to allow undefined key values to be used, such as `HTTP_HOST`, perhaps it can be used like the following (there is currently no specification, this is just the solution I envisioned). ```python class Environ(CGIRequiredDefined, CGIOptionalDefined, WSGIDefined, allow_undefined=True):     """     WSGI Environ     """ ``` Or is there a solution that I don’t know? --- Aber

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Typing-sig April 2021