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Re: Static regex for embedded systems

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On 21/01/2025 15:31, pozz wrote:
> Many times I need to parse/decode a text string that comes from an 
> external system, over a serial bus, MQTT, and so on.
> 
> Many times this string has a fixed syntax/layout. In order to parse this 
> string, I everytime create a custom parser that can be tedious, 
> cumbersom and error prone.
> 
> For example, suppose you have to decode a string from a modem that uses 
> AT commands. Many answers from the modem has the following schema:
> 
>    \r\n+<prefix>: <field1>,<field2>\r\n
>    \r\nOK\r\n
> 
> The prefix is known, the number and type of fileds are known too. With 
> regex, the parser would be simple.
> 

There are plenty of libraries for run-time regular expressions - they 
have been in the C++ standard library since C++11 (IIRC).  But run-time 
parsing of regex strings and matching for the input string will be very 
time and space costly in a small embedded system.  You want compile-time 
regular expression handling.

This had been planned for inclusion in C++23 (and therefore part of the 
current GNU ARM Embedded toolchain, if that's what you are using), but 
it didn't make it.  However, there are standalone compile-time regex 
libraries for C++ using templates and compile-time functions, which will 
in effect generate specialised parsers from the regex strings.

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Static regex for embedded systems pozz <pozzugno@gmail.com> - 2025-01-21 15:31 +0100
  Re: Static regex for embedded systems David Brown <david.brown@hesbynett.no> - 2025-01-21 16:40 +0100
  Re: Static regex for embedded systems Stefan Reuther <stefan.news@arcor.de> - 2025-01-21 17:03 +0100
    Re: Static regex for embedded systems pozz <pozzugno@gmail.com> - 2025-01-21 18:03 +0100
      Re: Static regex for embedded systems Hans-Bernhard Bröker <HBBroeker@gmail.com> - 2025-01-21 20:40 +0100
      Re: Static regex for embedded systems "Niocláiſín Cóilín de Ġloſtéir" <Master_Fontaine_is_dishonest@Strand_in_London.Gov.UK> - 2025-01-22 00:41 +0100
      Re: Static regex for embedded systems George Neuner <gneuner2@comcast.net> - 2025-01-21 19:38 -0500
        Re: Static regex for embedded systems David Brown <david.brown@hesbynett.no> - 2025-01-22 10:59 +0100
          Re: Static regex for embedded systems George Neuner <gneuner2@comcast.net> - 2025-01-22 18:23 -0500
        Re: Static regex for embedded systems Stefan Reuther <stefan.news@arcor.de> - 2025-01-22 17:53 +0100
          Re: Static regex for embedded systems George Neuner <gneuner2@comcast.net> - 2025-01-22 18:33 -0500

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