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cl:functions:math-one-plus [2019/09/14 05:00] |
cl:functions:math-one-plus [2019/09/22 06:00] (current) |
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+ | ====== Function 1+, 1- ====== | ||

+ | |||

+ | ====Syntax==== | ||

+ | * **1+** //number// → //successor// | ||

+ | * **1-** //number// → //predecessor// | ||

+ | |||

+ | ====Arguments and Values==== | ||

+ | * //number// - a //[[CL:Glossary:number]]//. | ||

+ | * //successor//, //predecessor// - a //[[CL:Glossary:number]]//. | ||

+ | |||

+ | ====Description==== | ||

+ | **1+** returns a //[[CL:Glossary:number]]// that is one more than its argument //number//. **1-** returns a //[[CL:Glossary:number]]// that is one less than its argument //number//. | ||

+ | |||

+ | ====Examples==== | ||

+ | <blockquote> | ||

+ | (1+ 99) <r>100 </r> | ||

+ | (1- 100) <r>99 </r> | ||

+ | (1+ ([[CL:Functions:complex]] 0.0)) <r>#C(1.0 0.0) </r> | ||

+ | (1- 5/3) <r>2/3 </r> | ||

+ | </blockquote> | ||

+ | |||

+ | ====Affected By==== | ||

+ | None. | ||

+ | |||

+ | ====Exceptional Situations==== | ||

+ | Might signal **[[CL:Types:type-error]]** if its //[[CL:Glossary:argument]]// is not a //[[CL:Glossary:number]]//. Might signal **[[CL:Types:arithmetic-error]]**. | ||

+ | |||

+ | ====See Also==== | ||

+ | * **[[CL:Macros:incf|Macro INCF]]** | ||

+ | * **[[CL:Macros:decf|Macro DECF]]** | ||

+ | |||

+ | ====Notes==== | ||

+ | <blockquote> | ||

+ | (1+ //number//) ≡ ([[CL:Functions:math-add|+]] //number// 1) | ||

+ | (1- //number//) ≡ ([[CL:Functions:math-subtract|-]] //number// 1) | ||

+ | </blockquote> | ||

+ | |||

+ | Implementors are encouraged to make the performance of both the previous expressions be the same. | ||

+ | |||