The following:

\starttext

\startMPinitializations

input cmarrows;

setup_cmarrows(arrow_name = "texarrow"; parameter_file = "cmr6.mf"; macro_name = "nicearrow");

\stopMPinitializations

\startMPpage

nicearrow (origin -- (1cm*left));

\stopMPpage

\stoptext

compiles perfectly with ConTeXt MkIV. With LMTX, however, the following happens:

metapost > initializing instance 'metafun:1' using format 'metafun' and method 'default'

metapost > loading 'metafun' as 'metafun.mpxl' using method 'default'

metapost > initializing number mode 'scaled'

metapost > message : Loading cmarrows 2006/12/18, v0.9

metafun > log > overloading immutable 'eps'

metafun > log >

metafun > log > error: Equation cannot be performed (numeric=pair)

metafun > log >

metapost > log >

metapost > log > <to be read again>

metapost > log > ;

metapost > log > <for((6.58641,1.4944))> z_[incr.n]:=(EXPR0);

metapost > log > ENDFOR

metapost > log > <argument> ...nt(length(path))of(path),z2,point.ttt.of(path),z9-(0,3rule_thickness#),point.tt.of(path)-3rule_thickness#*(unitvector(direction.tt.of(path))rotated90):z_[incr.n]:=z;endfor

metapost > log > ;transform.T...

metapost > log > hide->exitif.numeric.begingroup(TEXT0)

metapost > log > ;endgroup;

metapost > log > mapto->begingroup.hide(numeric.n;n:=0;numeric.x,x_[],y,y_[];for.z=(TEXT2):z_[incr.n]:=z;endfor;transform.T;z_2=z_1transformed.T;z_4=z_3transformed.T;z_6=z_5transformed.T;)

metapost > log > T.endgroup

metapost > log > nicearrow__sgbxww->...(z0,point(length(EXPR2))of(EXPR2),z2,point.ttt.of(EXPR2),z9-(0,3rule_thickness#),point.tt.of(EXPR2)-3rule_thickness#*(unitvector(direction.tt.of(EXPR2))rotated90))

metapost > log > ;fi.save.f,s...

metapost > log > <to be read again>

metapost > log > ;

metapost > log > <*> nicearrow (origin -- (1cm*left));

metafun > log >

metafun > log > I'm sorry, but I don't know how to make such things equal. (See the two

expressions just above the error message.)

metafun > log >

metapost > log > ;

metapost > log >

What's happening? Is that intended or a bug?

Jairo