さよならassert

C++ Grammar
  • 前回の続き
  • 要するにassertは意味が多すぎるので名前をつけよう、ということだ
    • バグ潰しのためなのか事前条件なのか分からないassertがよくある
  • 結局こうなった・・・ソースコード
    • postconditionがあるときのreturnがマクロになってしまった

[]#include[] []<pstade/contract.hpp>[]

[]#include[] []<cmath>[]

[]#include[] []<pstade/is_same.hpp>[]




[]inline[]

[]float[] []square_root[][]([][]float[] []x[][])[]

[]{[]

    []PSTADE_PRECONDITION[]

[]    ([]

[]        ([][]x[][] >= [][]0[][])[]

[]    )[]

    []PSTADE_POSTCONDITION[][]([][]float[][])[]

[]    ([]

[]        (([][]result[][] * [][]result[][]) == [][]x[][])[]

[]    )[]
    []PSTADE_RETURN[][]([][]std[][]::[][]sqrt[][]([][]x[][]));[]

[]}[]



[]struct[] []Date[]

[]{[]

    []Date[][]([][]int[] []month[][], [][]int[] []day[][]) :[]

        []m_month[][]([][]month[][]), [][]m_day[][]([][]day[][])[]

[]    {[]

        []PSTADE_CONSTRUCTOR_PRECONDITION[]

[]        ([]

[]            ([][]month[][] != [][]999[][])[]

[]            ([][]day[][] != [][]999[][])[]

[]        )[]

[]    }[]
[]    ~[][]Date[][]()[]

[]    {[]

        []PSTADE_DESTRUCTOR_PRECONDITION[]

[]        (~) [][]// empty[]

[]    }[]
    []void[] []set_xmas[][]()[]

[]    {[]

        []PSTADE_PUBLIC_PRECONDITION[]

[]        (~)[]

        []PSTADE_POSTCONDITION[][]([][]void[][])[]

[]        ([]

[]            ([][]m_month[][] == [][]12[][])[]

[]            ([][]m_day[][] == [][]25[][])[]

[]        )[]
        []m_month[][] = [][]12[][];[]
        []PSTADE_INVARIANT[][] ( ([][]m_month[][] == [][]12[][]) ) [][]// block invariant[]
        []m_day[][] = [][]25[][];[]
        []PSTADE_RETURN[][]([][]void[][]);[]

[]    }[]
    []template[][]< [][]class[] []T[][] >[]

    []T[][]& [][]set_day[][]([][]T[] []const[][]& [][]day[][])[]

[]    {[]

        []PSTADE_POSTCONDITION[][]([][]T[][]&)[]

[]        ([]

[]            ([][]result[][] == [][]day[][])[]

[]            ([][]pstade[][]::[][]is_same[][]([][]result[][], [][]m_day[][]))[]

[]        )[]
        []if[][] ([][]m_day[][] != [][]day[][]) {[]

            []m_day[][] = [][]day[][];[]

            []PSTADE_RETURN[][]([][]m_day[][]);[]

[]        }[]

        []else[][] {[]

            []PSTADE_RETURN[][]([][]m_day[][]);[]

[]        }[]

[]    }[]
[]private[][]:[]

    []int[] []m_month[][];[]

    []int[] []m_day[][];[]
    []PSTADE_CLASS_INVARIANT[]

[]    ([]

[]        ([][]1[][] <= [][]m_month[][] && [][]m_month[][] <= [][]12[][])[]

[]        ([][]1[][] <= [][]m_day[][] && [][]m_day[][] <= [][]31[][])[]

[]    )[]

[]};[]