Conditional Assertion

Date: 2016-02-19 08:01:55 +0000

The scenario that lead to this idea does not occur much but I thought it would be good to take a note of it. Here is a made-up function that slightly captures the use case.

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10 void check(std::vector<int> lines) {
    auto size = lines.size();
    ASSERT(size > 0);
    if (size <= 2) {
        ASSERT(lines[0] == 1);
    } elseif (size > 2) {
        ASSERT(lines[lines.size() - 1] == 1);
    }
    ...
}

Using something like a conditional assert macro would unclutter it a bit.

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7 void check(std::vector<int> lines) {
    auto size = lines.size();
    ASSERT(size > 0);
    IF_ASSERT(size <= 2, lines[0] == 1);
    IF_ASSERT(size > 2, lines[size - 1] == 1);
    ...
}

The idea is that if a certain pre-condition is true then the assert condition is evaluated and that if the assert condition evaluates to false then an assertion is triggered.

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6 #define IF_ASSERT(precond, cond, ...)       \
    do {                                    \
        if (!!(precond)) {                  \
            ASSERT(cond, ##__VA_ARGS__);    \
        }                                   \
    } while ((void)0, 0)

assertion
thoughts