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Examples > E-mail address > Syntax specification
Following syntax specification can be found in the book: J.E.F. Friedl: Reguläre Ausdrücke, O'Reilly, 1998.
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Element
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Description
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1
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mailbox
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addr-spez | phrase route-addr
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2
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addr-spec
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local-part @ domain
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3
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phrase
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( word )+
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4
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route-addr
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< ( route )? addr-spez >
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5
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local-part
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word (. word)*
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6
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domain
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sub-domain (. sub-domain )*
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7
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word
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atom | quoted-string
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8
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route
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@ domain (, @ domain )* :
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9
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sub-domain
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domain-ref | domain-literal
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10
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atom
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( a character except specials, space or ctl )+
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11
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quoted-string
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" ( qtext | quoted-pair )* "
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12
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domain-ref
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atom
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13
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domain-literal
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( dtext | quoted-pair )*
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14
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char
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An ASCII character (octal 000-177)
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15
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ctl
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An ASCII control character (octal 000-037)
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16
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space
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Space (ASCII 040)
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17
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CR
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Carriage Return (ASCII 015)
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18
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specials
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One of the characters ()<>@,;:\\"\.\[\]
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19
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qtext
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A char except *, \ or CR
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20
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dtext
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A char except [, ], \ or CR
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21
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quoted -pair
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\ char
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22
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comment
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( (ctext | quoted-pair | comment )* )
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23
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ctext
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A char except (, ), \ or CR
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From this specification Friedl constructs a single regular expression consisting in 4724 characters. The direct use in the TextTransformer has approximately the length of specification itself.
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