I-structures (I = incremental)
Problem: Single-assignment rule and complex data structures
- each update of a data structure consumes the structure and the value producing a new data structure.
- awkward or even impossible to implement.
Solution: concept of I-structure:
- a data repository obeying the single-assignment rule
- each element of the I-structure may be written only once but it may be read any number of times
The basic idea is to associate with each element status bits and a queue of deferred reads.