Object models for computer aided design

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23 􁪽􋴚􁪽􋴚􁪽􋵣ch 6e 􁪽􋵣ct deal 􁪽􋵩ith the data ctject as a 􁪽􋴚􁪽􋵣cle. The cc􁪽􋴚􁪽􋵣c􁪽􋴺 :􁪽􋴻;e5 c􁪽􋴚 􁪽􋵮n􁪽􋵥eger, real, 􁪽􋵳ser def􁪽􋴚􁪽􋵥e6 􁪽􋵹ypes such as "day c􁪽􋵴 the week" o􁪽􋵴 tt􁪽􋵳s class. si􁪽􋵣ce these types 3re fixed in lengtt, one ca􁪽􋵴 tt􁪽􋴚􁪽􋴚􁪽􋵲 r- 􁪽􋵨he memory locatic􁪽􋵳s to which the variatles are bound 􁪽􋵳s "co:;t.a:.ners". The values for these tv􁪽􋵥es 􁪽􋵕U!t be selec:e6 fro􁪽􋵡 a 􁪽􋴚􁪽􋵶ven sirr?le dorra􁪽􋵮n so the rrathe􁪽􋵡atical e􁪽􋵵u:valEr.: :s a sinsle set. 2.3.2 Recorc Structures A record s t r uc t u r e rr.a::· be defined as a fixed len?tt, ordered se􁪽􋵵uence 0: s?ecified record ty?es or un5tr􁪽􋵣ctured 6ata types. O?era􁪽􋵩ion5 are defined on records which select elements from the record. An example of a r e cor d rn ; 􁪽􋵛 [; t be" d ate" io.' h i c M c c :..: 2. d bed e f i ned a s e 5 e 0 u e n c e a : "" .. .I..:eJ.cs "day", "n or.t.h!", and "year" . records are also fixed length, contiguous areas of rrerrory rre y be COL.:IiC as "c c n t a i ne r s " for record variables. 7he 􁪽􋵡a:he􁪽􋵡atical ecuivalent of a record is a cartesian ?rocuct of the co􁪽􋵰posite dOffiain set!. Arrays rr.ay be recursively defined as the cartesian product of a base set with itself n times w􁪽􋵥ere n is the di􁪽􋵥ensicn of the array. The ba􁪽􋵥e set may either be another array, recore, or an unstructured data type.