text_uppercase:n not working in ConTeXt MkIV

[ghost]

The following:

\input expl3-generic
\ExplSyntaxOn
\cs_new_protected:Npn \myuppercase #1
{\text_uppercase:n{#1}}
\ExplSyntaxOff
\starttext  
\myuppercase{aéreos août}
\stoptext 

does not work in ConTeXt. The log file says:

<argument> \e@alloc@ccodetable@count 
                          
\int_compare:nNnTF #1#2#3->\if_int_compare:w \__int_eval:w #1#2\__int_eval:w #3
                                                            \__int_eval_end: \exp_after:wN \use_ii:nnn \fi: \use_ii:nn 
<argument> \__cctab_chk_if_valid_aux:NTF \c_other_cctab 
                                             {\prg_return_true: }{\__kernel_msg_error:nnx {kernel}{invalid-cctab}{\token_to_str:N \c
\use_i:nn #1#2->#1
        
\__cctab_chk_if_valid:NT ...ror:nnx {kernel}{command-not-defined}{\token_to_str:N #1}\prg_return_false: }
                                                                                \exp_end: \use:n \use_none:n 
\cctab_gset:Nn #1#2->\__cctab_chk_if_valid:NT #1
                                 {\group_begin: \cctab_select:N \c_initex_cctab #2\scan_stop: \__cctab_gset:n {#1}\group_end: }
l.20373   }

\e@alloc@ccodetable@count seems to be defined in LuaLaTeX, but not ConTeXt. Defining a counter does not work.

For comparison, the code above works for LuaLaTeX and gives the same result as ConTeXt's \WORDS, i.e. AÉREOS AOÛT.

UPDATE: It seems the whole expl3 is unusable with ConTeXt (2020.07.24 16:57).

[josephwright]

I can see where this comes from: I'll have to dig through ConTeXt to find the allocator for category code tables.

[josephwright]

OK, we need to check on \c_syst_catcodes_n, should be easy enough