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27 lines
970 B
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27 lines
970 B
Plaintext
Iso-Functional Type Contour
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This is a term coined to describe "column int->float" change approach, and can
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be used whenever low-level types need to change (hopefully not often!) but the
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meanings of the values (whose type has changed) do not.
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The premise is that changing a low-level type potentially means lots of code
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needs to be changed as well, and the question is how to do this incrementally,
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which is the preferred way to change things.
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Say LOW and HIGH are C functions:
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int LOW (void) { return 1; }
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void HIGH (void) { int value = LOW (); }
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We want to convert LOW to return float, so we cast HIGH usage:
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float LOW (void) { return 1.0; }
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void HIGH (void) { int value = (int) LOW (); } /* iftc */
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The comment /* iftc */ is used to mark this type of casting to differentiate
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it from other casting. We commit the changes and can now go about modifying
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LOW and HIGH separately. When HIGH is ready to handle the type change, the
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cast can be removed.
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