Syntax of a Ratio (ANSI and GNU Common Lisp Document)

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2.3.2.3 Syntax of a Ratio ¶

Ratios can be written as an optional sign followed by two non-empty sequences of digits separated by a slash; see Figure~2–9. The second sequence may not consist entirely of zeros. Examples of ratios are in Figure 2–13.

  2/3                 ;This is in canonical form                  
  4/6                 ;A non-canonical form for 2/3               
  -17/23              ;A ratio preceded by a sign                 
  -30517578125/32768  ;This is (-5/2)^15                        
  10/5                ;The canonical form for this is 2           
  #o-101/75           ;Octal notation for -65/61                  
  #3r120/21           ;Ternary notation for 15/7                  
  #Xbc/ad             ;Hexadecimal notation for 188/173           
  #xFADED/FACADE      ;Hexadecimal notation for 1027565/16435934  

                  Figure 2–13: Examples of Ratios

[Reviewer Note by Barmar: #o, #3r, #X, and #x mentioned above are not in the syntax rules defined just above that.]

For information on how ratios are printed, see Printing Ratios.