Abstract syntax: N elem-of Nml = binary numerals

    N ::= I F
    I ::= B | I B
    F ::= .B | .B F
    B ::= 0 | 1

Semantic domain: Z = real numbers

Semantic function: Nm: Nml -> Z

    Nm[[I F]] = Nm[[I]] + Nm[[.F]]
    Nm[[I B]] = 2*Nm[I] + Nm[[B]]
    Nm[[0]] = 0
    Nm[[1]] = 1
    Nm[[.B F]] = Nm[[.B]] + Nm[[.F]]/2
    Nm[[.0]] = 0
    Nm[[.1]] = 1/2

Test case: 1101.01
    Nm[[1101.01]] \kw= Nm[[1101]] + Nm[[.01]]
.ta \nwu
	= (2*Nm[[110]] + Nm[[1]]) + (Nm[[.0]] + Nm[[.1]]/2)
	= (2*(2*Nm[[11]] + Nm[[0]]) + Nm[[1]]) + (Nm[[.0]] + Nm[[.1]]/2)
	= (2*(2*(2*Nm[[1]] + Nm[[1]]) + Nm[[0]]) + Nm[[1]]) + (Nm[[.0]] + Nm[[.1]]/2
	= (2*(2*(2*1 + 1) + 0) + 1) + (0 + (1/2)/2)