princ, print, pretty_princ, pretty_print

Gamma: Version 4.0
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# `princ`, `print`, `pretty_princ`, `pretty_print`

`princ`, `print`, `pretty_princ`, `pretty_print` -- write to the standard output file.

## Syntax

    princ (s_exp...)
    print (s_exp...)
    pretty_princ (s_exp...)
    pretty_print (s_exp...)

## Arguments

`s_exp`

  Any Gamma or Lisp expression.

## Returns

t

## Description

These functions write to the standard output file, typically the screen. The `princ` and `pretty_princ` functions produce formatted output, which means that special characters are not escaped, and double quotes are not printed around character strings. Output generated by `princ` cannot be read by the Lisp reader.

`print` and `pretty_print` produce Lisp-readable output. The result of reading a printed expression using a call to `read` will generate an equal expression.

`pretty_princ` and `pretty_print` generate carriage returns and spaces with the intention of formatting the output to make long or complex Lisp expressions easier for a person to read.

## Examples

        Gamma> x = "hello";
        "hello"
        Gamma> print (x,"\n");
        "hello""\n"t
        Gamma> princ (x,"\n");
        hello
        t
        Gamma> >

        Gamma> class C {a; b; c;}
        (defclass C nil [][a b c])
        Gamma> princ (C);
        (defclass C nil [][a b c])t
        Gamma> pretty_princ (C);
        (defclass C nil
        []
        [a b c])t
        Gamma>

        Gamma> L = list (1,2,3,4,5,list(1,2,3,4,5,list(1,2,3
        list(1,2,3,4,5,list(1,2,3,4,5,list(1,2,3,4,5,list(1,2
        ,list(1,2,3,4,5,list(1,2,3,4,5)))))))))));
        (1 2 3 4 5 (1 2 3 4 5 (1 2 3 4 5 (1 2 3 4 5 (1 2 3 4
        4 5 (1 2 3 4 5 (1 2 3 4 5 (1 2 3 4 5 (1 2 3 4 5)))))
        Gamma> princ (L);
        (1 2 3 4 5 (1 2 3 4 5 (1 2 3 4 5 (1 2 3 4 5 (1 2 3 4
        4 5 (1 2 3 4 5 (1 2 3 4 5 (1 2 3 4 5 (1 2 3 4 5)))))
        Gamma> pretty_princ (L);

        (1 2 3 4 5
           (1 2 3 4 5
              (1 2 3 4 5
                 (1 2 3 4 5
                    (1 2 3 4 5
                       (1 2 3 4 5
                          (1 2 3 4 5 (1 2 3 4 5 (1 2 3 4 5 (
        ))))))))))t
        Gamma>

See the Starting Programs section of the Common Functions chapter (Tutorial One) in the Cogent Tools Demo and Tutorials book for an example of this function used in context.

## See Also

`write, writec, pretty_write`

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