# ei\_x\_format doesn't support map term

**URL:** <https://erlangforums.com/t/ei-x-format-doesnt-support-map-term/2837>\
**Category:** Proposals: RFC\
**Tags:** erl\_interface\
**Created:** [August 30, 2023, 11:38am UTC](https://erlangforums.com/t/ei-x-format-doesnt-support-map-term/2837 "2023-08-30T11:38:38Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![fregate](https://erlangforums.com/letter_avatar_proxy/v4/letter/f/97f17d/32.png) [@fregate](https://erlangforums.com/u/fregate)\
**Post date:** [August 30, 2023, 11:38am UTC](https://erlangforums.com/t/ei-x-format-doesnt-support-map-term/2837/1 "2023-08-30T11:38:38Z")

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Hi all  
I’ve already mentioned it here

> <https://github.com/erlang/otp/issues/7598>
>
> \*\*Describe the bug\*\*
> In function https://github.com/erlang/otp/blob/d9fd6615141…d2fc555b170fb47e71c8abcf19727/lib/erl\_interface/src/misc/ei\_format.c#L67
> no case to encode map term
> 
> \*\*To Reproduce\*\*
> \`\`\`
> ei\_x\_buff buf;
> ei\_x\_new(&buf);
> int res = ei\_x\_format(&buf, "#{a=\>1}"); // -1
> \`\`\`
> 
> \*\*Expected behavior\*\*
> Map as a term in Erlang was introduced many versions ago and there is no support in ei library still.
> 
> \*\*Affected versions\*\*
> Current and all previous

There is no support in `ei_x_format(*)` to work with map term. Map was introduced in erlang decade ago and there is still no support.  
`ei_x_format(&buf, "#{a=>1}")` returns -1

Is it some decision about this or just no one use it at all?

I have my own implementation, but I don’t understand, how to run test suite for erl\_interface\_test to create good PR in github.