Lazy Evaluation

4.10 Lazy Evaluation

TBoS p.137-141

Shen provides on-demand type secure lazy evaluation; the function 'freeze' creates an object b; from its argument a without evaluating a. The function 'thaw' takes b and evaluates it to the normal form of a. These functions satisfy the equation (thaw (freeze a)) = a.

(0-) (freeze (factorial 8))
FUNCTION :LAMBDA NIL (factorial 8)

(1-) (thaw (freeze (factorial 8)))
40320

4. The Core Language

4.6 Sequences

5 Defining Functions

6. Packages

7. Shen-YACC

8. Shen Prolog

9. Types

10 Sequent Calculus

10.2 Exotic Types