The Record Format Constructor

The special constructor recformat< ... > is used for the creation of record formats. A record format must be created before records in that format are created.

recformat< L >: FieldnameList -> RecFormat

Construct the record format corresponding to the non-empty fieldname list \(L\). Each term of \(L\) must be one of the following:

(a)

fieldname in which case there is no restriction on values that may be stored in this field of records having this format;

(b)

fieldname:expression where the expression evaluates to a magma which will be the parent of values stored in this field of records having this format; or

(c)

fieldname:expression where the expression evaluates to a category which will be the category of values stored in this field of records having this format;

where fieldname consists of characters that would form a valid identifier name. Note that it is not a string.

Example: Creating a Record Format (ex-d1148b)

We create a record format with these fields: n, an integer; misc, which has no restrictions; and seq, a sequence (with any universe possible).

> RF := recformat< n : Integers(), misc, seq : SeqEnum >;
> RF;
recformat<n: IntegerRing(), misc, seq: SeqEnum>
> Names(RF);
[ n, misc, seq ]

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