with-standard-io-syntax

ToC

Allegro CL

ANSI Common Lisp

23 Reader

23.2 Dictionary of Reader

23.2.12 with-standard-io-syntax

Macro

Syntax:

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 the next figure.

Values of standard control variables
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

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))))

Allegro CL Implementation Details:

See The standard readtable is read-only, affect on with-standard-io-syntax and modifying the readtable in init files and with -e in implementation.html for a note on the binding of *readtable* in a with-standard-io-syntax call.