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41 lines
1.7 KiB
41 lines
1.7 KiB
5 years ago
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title = "Things I Learnt The Hard Way - Types Say What You Data Is"
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date = 2019-06-24
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[taxonomies]
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tags = ["en-au", "books", "things i learnt", "types"]
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Memory is just a sequence of bytes; bytes are just numbers from 0 to 255; what
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those numbers mean is described on the language type system.
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<!-- more -->
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For example, in C, a `char` type of value 65 is most probably the letter "A",
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which an `int` of value is 65 is the number 65.
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Remember this when dealing with your data.
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And it doesn't matter of your language of choice uses dynamic typing or static
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typing. The same still applies.
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One classic example of misusing types is adding booleans. Booleans are either
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`true` or `false`, but because most languages follow C, which doesn't have a
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boolean type and uses compiler pre-processors to define `TRUE` as an integer
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with the value `1` and `FALSE` with another integer with the value `0`. And
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so, the build on top of what older developers knew, other languages use the
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same concepts. And so, you have a list of booleans and want to know how many
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true values are in the list, you can simply add them all.
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Let me point that again: You're adding booleans and expecting a number.
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No, you're counting the number of elements in the list 'cause that would see
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the whole list. You're not even filtering the false values over and counting
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the resulting list size. You're jumping the underlying type to get a bit of
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performance out.
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Fortunately, new languages are based on ML, which wouldn't allow this kind of
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stuff.
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{{ chapters(prev_chapter_link="/books/things-i-learnt/handle-it", prev_chapter_title="If You Know How To Handle It, Handle It", next_chapter_link="/books/things-i-learnt/languages-are-more", next_chapter_title="A Language Is Much More Than A Language") }}
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