$PreRead

$PreRead is a global variable whose value, if set, is applied to the text or box form of every input expression before it is fed to Mathematica.

$PreRead is always applied to each complete input string that will be fed to Mathematica.

In multiline input with a text-based interface, $PreRead is typically applied to the input so far whenever each line is terminated.

$PreRead is applied to all strings returned by a $SyntaxHandler function.

$PreRead is applied before InString[n] is assigned.

See Section 2.14.1.

See also: $Pre, StringReplace, ToExpression.

New in Version 2.