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A comment on Python 3 Types in the Wild. Parent comment

Re:Python 3 Types in the Wild by dllthomas on Sunday March 20, 2022 @11:54AM (#30743708)
Only in the same way that "if ... else if ... else" needs to know about types, which is to say mostly not.

AFAIK - and this might be either dated or just wrong - the two places GHC doesn't fully erase are 1) polymorphic recursion (where if we squint it's probably not unreasonable to treat the dictionaries as type tags), and 2) when the programmer explicitly asks for run-time type information with Typeable.

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Re:Python 3 Types in the Wild by whimsicalism on Sunday March 20, 2022 @02:27PM (#30745225)
But what are you performing the "if else" on? Type level information stored at runtime, no?
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Re:Python 3 Types in the Wild by dllthomas on Sunday March 20, 2022 @06:16PM (#30747264)
Value level information. The compiler statically knows the type that's being matched on. It's true that the generated code depends on the type, but that's not any more true than when a C compiler generates an integer comparison vs a float comparison in the conditional of that "if". All that's looked at at runtime is the data.
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