On 26/05/2011 16:48, Leonardo Moretti wrote: > Hi all, > I thought a lot on your proposal. > > If we want to use pseudo-units (non-UCUM terms), then we have to be able to > distinguish when a term is in UCUM syntax. For example g/m2.7 is a valid > UCUM string, but it is interpreted as (g/m^2) * 7 and not as g/(m^2.7), > because in UCUM ?.? is the symbol for multiplication operator. > So ?units? attribute should become a sort of code phrase, with the > information on adopted syntax. Otherwise we can have an ambiguous syntax.
I am surprised that precedence does not force the reading of the full number following a '^', or a unit like 'm' when the '^' is inferred. I will have to look at my own UCUM parser to see what it does! > As alternative, if we want to go on using only UCUM syntax, we could express > this pseudo-unit (and not standard units) with the so-called annotation, > wrapped in curly braces (see > http://aurora.regenstrief.org/~ucum/ucum.html#section-Character-Set-and-Lexical-Rules, > section 6). In this case, we can adopt {g/m2.7} safely, remaining compliant > with the UCUM syntax. I actually think that is a good idea. Have you looked for a mailing list or place in HL7 where you can make that proposal? - thomas beale
