Runtime evaluation/In an environment: Difference between revisions

{{task}} Given a program in the language (as a string or AST) with a free variable named <var>x</var> (or another name if that is not valid syntax), evaluate it with <var>x</var> bound to a provided value, then evaluate it again with <var>x</var> bound to another provided value, then subtract the result of the first from the second and return or print it.

 

Do so in a way which:

* is plausibly extensible to a runtime-chosen set of bindings rather than just <var>x</var>

* does not make <var>x</var> a ''global'' variable

or note that these are impossible.

 

===See also===

* For more general examples and language-specific details, see [[Eval]].

* [[Dynamic variable names]] is a similar task.

 

=={{header|ALGOL 68}}==