check-recursion ( obj quot: ( obj -- ) -- )

Vocabulary

prettyprint.backend

Inputs

obj	an object
quot	a quotation with stack effect ( obj -- )

Outputs

None

Word description

If the object is already being printed, that is, if the prettyprinter has encountered a cycle in the object graph, or if the maximum nesting depth has been reached, outputs a dummy string. Otherwise applies the quotation to the object.

Notes

This word should only be called from inside the with-pprint combinator.

Definition

USING: accessors classes kernel namespaces prettyprint.sections
sequences ;

IN: prettyprint.backend

: check-recursion ( obj quot: ( obj -- ) -- )
    nesting-limit?
    [ drop [ class-of name>> "~" 1surround ] keep present-text ] 
    [
        over recursion-check get member-eq?
        [ drop "~circularity~" swap present-text ] [
            over recursion-check get push call
            recursion-check get pop*
        ] if
    ] if ; inline