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23.2.12 with-standard-io-syntax [Macro]

with-standard-io-syntax {form}*{result}*

Arguments and Values::

forms—an implicit progn.

results—the values returned by the forms.

Description::

Within the dynamic extent of the body of forms, all reader/printer control variables, including any implementation-defined ones not specified by this standard, are bound to values that produce standard read/print behavior. The values for the variables specified by this standard are listed in Figure 23–1.

[Reviewer Note by Barrett: *print-pprint-dispatch* should probably be mentioned here, too.]

  Variable                     Value                               
  *package*                    The CL-USER package                 
  *print-array*                t                                   
  *print-base*                 10                                  
  *print-case*                 :upcase                             
  *print-circle*               nil                                 
  *print-escape*               t                                   
  *print-gensym*               t                                   
  *print-length*               nil                                 
  *print-level*                nil                                 
  *print-lines*                nil                                 
  *print-miser-width*          nil                                 
  *print-pprint-dispatch*      The standard pprint dispatch table  
  *print-pretty*               nil                                 
  *print-radix*                nil                                 
  *print-readably*             t                                   
  *print-right-margin*         nil                                 
  *read-base*                  10                                  
  *read-default-float-format*  single-float                        
  *read-eval*                  t                                   
  *read-suppress*              nil                                 
  *readtable*                  The standard readtable              

         Figure 23–1: Values of standard control variables        

Examples::

 (with-open-file (file pathname :direction :output)
   (with-standard-io-syntax
     (print data file)))

;;; ... Later, in another Lisp:

 (with-open-file (file pathname :direction :input)
   (with-standard-io-syntax
     (setq data (read file))))