Re: [Boost-users] Simple XML parser - error handling - line number

Subject: Re: [Boost-users] Simple XML parser - error handling - line number
From: Steven Watanabe (watanabesj_at_[hidden])
Date: 2018-06-29 20:21:54

AMDG

On 06/29/2018 12:43 PM, AndrzejB via Boost-users wrote:
> I see tutorial sample:
> https://www.boost.org/doc/libs/1_67_0/libs/spirit/example/qi/mini_xml3.cpp
> <https://www.boost.org/doc/libs/1_67_0/libs/spirit/example/qi/mini_xml3.cpp>  
> 			on_error<fail>
> 				(
> 					xml
> 					, std::cout
> 					<< val("Error! Expecting ")
> 					<< _4                               // what failed?
> 					<< val(" here: \"")
> 					<< construct<std::string>(_3, _2)   // iterators to error-pos, end
> 					<< val("\"")
> 					<< std::endl
> 					);
> How print line number,

The parser doesn't track line numbers at all.
If you want to print it, you'll need to add
something to count new lines.

> or how print _2 and _3 . If I write _2 instead _4, is
> compiler error.
> 

_2 and _3 are iterators.  You can't print them directly.
Hence why this code constructs a string from them.

In Christ,
Steven Watanabe