R function: expression

Capturing an expression

expression(…) captures the expression within the parenthesis without evaluating it.

When the (returned) expression value is printed, the captured expression is still there:

expr <- expression(7 * 6);
print(expr);
#
#  expression("7 * 6")

An expression can then be evaluated:

expr <- expression(7 * 6);

eval(expr);
#
#  42