Overview

The constraint language LOCA that we have used here is an alternative concrete syntax for a subset of the OCL 2.0 specification notation.

In LOCA we only use the OCL types OclAny (the supertype of booleans, numerics and strings), Boolean, Integer, Real and String, and the parameterised types Collection < T >, Set < T > and Sequence < T > (Figure C.1). Integer is a true subtype of Real since all operations of reals are applicable to integers and have the same results on integers.

Figure C.1: LOCA type hierarchy

Table C.1 shows the mapping of LOCA syntax to normal OCL syntax. e' denotes the translation of e.

Table C.1: Correspondence of OCL and LOCA

LOCA	OCL	Note
OclAny
x = y	x' = y'
x / = y	x' < > y'
Real
x + y	x' + y'	Likewise for -, /, *
x < y	x' < y'	Likewise for >, <=, >=
x.abs	x'.abs()	Likewise for floor, round, sqrt, sqr
{ n 1, , n m} .max		Numeric expressions n 1, , n m
{ n 1, , n m} .min		Numeric expressions n 1, , n m
{ n 1, , n m} .sum		No duplicates in n 1, , n m
Integer		Above operations...