Scheme (programming language): Difference between revisions

Revision as of 20:14, 26 October 2023

Revision as of 04:55, 6 November 2023

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<code>interaction-environment</code> is the interpreter's global environment.

===Treatment of non-booleanBoolean values in booleanBoolean expressions===

In most dialects of Lisp including Common Lisp, by convention the value <code>NIL</code> evaluates to the value false in a booleanBoolean expression. In Scheme, since the IEEE standard in 1991,<ref name="ieee1178"/> all values except <code>#f</code>, including <code>NIL</code>'s equivalent in Scheme which is written as <code>'()</code>, evaluate to the value true in a booleanBoolean expression. (R5RS sec. 6.3.1)<ref name="r5rs"/>

Where the constant representing the booleanBoolean value of true is <code>T</code> in most Lisps, in Scheme it is <code>#t</code>.

===Disjointness of primitive datatypes===