Concatenation and Matrix definition in BandMathX

Description

In BandMathX there are two conflicting operators: matrix definition and concatenation

It is possible to concatenate the result of two expressions by using a semicolon "exp1 ; exp2" (this is converted to "cat(exp1,exp2)"

In muParserX syntax, matrices can be defined as {m11, m21, m31 ; m12, m22, m32 ; m13, m32, m33}. But when using this expression in BandMathX the semicolons separating rows are interpreted as the concatenation operator.

Note that it is possible to define matrices in a context file and use them in the expression without having this problem.

Do we really the ; concatenation operator ? expression can also be concatenated with the expression "cat(exp1, exp2)"

Another solution would be to replace the ; for concatenation by cat, i.e; exp1 cat exp2 would be converted into cat(exp1, exp2)

See https://forum.orfeo-toolbox.org/t/multivariate-alteration-detection-use-on-different-images/428/6