如何在Haskell中获得一个callstack？ [英] How do I get a callstack in Haskell?

问题描述

我试图追踪图书馆代码中的一个非穷尽的模式。具体来说HDBC的mysql实现。它试图在我的程序中匹配类型，并将它们映射到我认为的mysql类型。我似乎无法得到这个错误的调用堆栈，这意味着由于SQL查询中有许多参数，所以很难准确地跟踪导致它的原因。

是否可以在haskell中获取一个callstack，以便我知道哪个参数导致错误？我也会认为这应该被编译器所捕获，因为它应该能够查看我的类型和模式，并确保有一个相应的匹配。

解决方案

您可以使用确定异常来自哪里。

我走过一个完整的例子这里。

I am trying to track down a non-exhaustive pattern in a libraries code. Specifically HDBC's mysql implementation. It is trying to match over types in my program and map them to mysql's types I believe. I can't seem to get a callstack for this error which means that since there are a number of parameters to the SQL query it is difficult to track down exactly what is causing it.

Is it possible to get a callstack in haskell so I would know which parameter was causing the error? Also I would think that this should be caught by the compiler since it should be able to look at my types and the patterns and make sure that there was a corresponding match.

解决方案

You can use the GHCi debugger to identify where the exception is coming from.

I walk through a full example here.

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