escape sequence for special hex values

[espruino-discuss3]

Posted at 2015-05-02 by AntiCat

Hi

I'm assembling a string of special characters e.g.:

 print("\x10\x20\x10");

While it works flawlessly on the Espruino the IDE marks \x20 as unnecessary escapement. Note, \x10 is not marked. I assume its a bug in the IDE?

[espruino-discuss3]

Posted at 2015-05-03 by DrAzzy

\x20 is unneccessary escaping, because it's a normal space, hence doesn't need an escape.

Ascii code 0x20 (32) is space.

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Posted at 2015-05-03 by AntiCat

Great catch! I haven't looked at it from that angle.

However, I'm using escape sequences like the one above to include parts (2 to 32 bytes) of a binary protocol . They are sent out on the serial interface.

Replacing all printable characters in the sequence would be cumbersome and error prone. Can such warnings be disabled?

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Posted at 2015-05-05 by @gfwilliams

I'm afraid they can only be disabled by tweaking the IDE's code at the moment... I guess maybe a more readable (if marginally less efficient) way of writing it might be:

String.fromCharCode(0x10,0x20,0x10)

But it depends where you're sending the data. If it's down SPI/I2C then you can just send an array of values rather than a string. You can even do it with the Serial ports using write:

Serial1.write([0x10,0x20,0x10]) 

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Posted at 2015-05-07 by AntiCat

The alternative forms look nice! Thank your for the suggestion.