LISP: Type specifiers in lisp

1. Type specifiers in Lisp

3. Predicating Type specifies

4. Type specifies:

5. That Combine

6. That specialize

7. That abbreviate

8. Defining new type specifies

9. Type conversion function

11. Type specifier symbols Standard type specifier symbols are: array fixnum package simple-string atom float pathname simple-vector bignum function random-state single-float Bit hash-table ratio standard-char Bit -vector integer rational stream character keyword readtable string [common ] list sequence string char Compiled-function long-float short-float symbol complex nil signed-byte t cons null simple-array unsigned-byte Double-float number simple-bit-vector vector

15. The call (typep x ‘ (satisfies p)) assigns p to x and returns t if true and returns nil if the result is false.Ex: (deftype string-char() ' (and character (satisfies string-char-p)))  STRING-CHAR

18. Types can be of two different purposes:

19. declaration( declaring to make array that elements will always be of type short-float permits optimization.)

21. (vector element-type size)  set of one dimensional arrays whose elements are of type element type and whose length is eq ti size. Ex: (vector *5) vector of length 5 ( vector double-float) floating-point numbers. (simple-vector size)  specifies that the elements are of simple general vectors. (complex type1)  every element of this type is a complex number whose real part and imaginary part are each of type type1)

24. (unsigned-byte s) set of non-negative integers that can be represented in a byte of s bits. (string size) set of strings of indicated size. (base-string size) set of base strings of indicated size (bit-vector size)set of bit-vectors of indicated size.

26. the deftype special form can be used to define new type-specifier abbreviations.Syntax: deftype name lambda-list [{declaration}* | doc-string ] {form}* [macro] Name is the symbol that identifies the type specifier Form constitutes the body of expander function Ex: (deftype mod (n) ‘ (integer 0 ( ,n)))