The three "complex functions" cabs2(), creal(), and cimag()
are being parsed as if they return a vector but they don't.
In the file express.c, in function Parse_Num_Factor(), those
three cases (CABS2_TOKEN, CREAL_TOKEN, and CIMAG_TOKEN)
have to be moved up in the Parse_Num_Factor to where they will be
parsed as returning floats.
