How to split an RegEx into several lines for readabili

As I am an absolute RegEx beginner, please excuse me if this is a
trivial question.

<xsl:analyze-string select="$vstrInput"
regex='([\s]*)(("[^"\\]*((\\.[^"\\]*)*"))|((([-]?[0-9]+)?\.)?[-]?[0-9]+([eE][-+]?[0-9]+)?
))(.*)$' flags="m">

which should match only the first quoted-string or number in the
string-argument.

Is there any way I can split this RegEx on separate lines and/or add
whitespace so that it would be more readable?

--
Cheers,
Dimitre Novatchev
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Truly great madness cannot be achieved without significant intelligence.
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To invent, you need a good imagination and a pile of junk
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You've achieved success in your field when you don't know whether what
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