3.1.4 Changes to Common Lisp character operations

3.1.4.2 Changes to support bits and font attributes

The character attribute functions and their related constants have been dropped from the Common Lisp standard. Liquid Common Lisp retains the following constructs as extensions to Common Lisp:

char-bit char-bits char-bits-limit char-control-bit char-font char-font-limit char-hyper-bit char-meta-bit char-mouse-bit

char-super-bit int-char make-char set-char-bit string-char-p

The function char-code returns the non-negative integer that encodes its character argument. It ignores bits and font attributes.

The function code-char takes an optional bits argument in addition to its code argument followed by an optional font argument.

The function char-int returns the non-negative integer that encodes its character argument. If the bits and font attributes of a character are 0, the results ofchar-int andchar-code are the same.

The optional font argument to the function digit-char has been retained as an extension to Common Lisp.

Characters within a particular character set are compared by using their character external code according to the ordering given by Figure 3.1 on page 18.

Character comparison operations treat bits and font attributes as follows:

If characters differ in either their code, bits, or font attributes, they are considered to be different.
The predicateschar=,char/=,char<,char>,char<=, andchar>= compare bits and font attributes. If characters agree in their bits and font attributes, they are compared according to their code attributes.
The predicateschar-equal,char-not-equal,char-lessp,char-greaterp,char-not-greaterp, andchar-not-lessp ignore differences in bits and font attributes.

International Character Sets - 9 SEP 1996

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