185     "

   186 !

   187 

   188 readFrom:aStringOrStream format:formatString language:languageOrNil onError:exceptionalValue

   189     "return a new Time, reading a printed representation from aStream using a formatString.

   190      The formatString is similar to the one used when printing.

   191      On error, exceptionalValue is returned.

   192      If exceptionalValue is a one-arg block, an error message is passed as argument.

   193      Format:

   194         %h      hours, 00..23 (i.e. european)  0-padded to length 2

   195         %u      hours, 00..12 (i.e. us)        0-padded to length 2

   196         %m      minutes, 00..59                0-padded to length 2

   197         %s      seconds, 00..59                0-padded to length 2

   198         %i      milliseconds, 000..999         0-padded to length 3

   199         %a      am/pm

   200 

   201      an optional length after the % gives a field length;

   202         i.e. %2h%2m%2s parses '123557' as 12:35:37

   203 

   204      Please consider using a standard format, such as iso8601.

   205     "

   206 

   207     |hour minute second millisecond

   208      utcOffset inStream formatStream error fChar format itemHandler

   209      len s|

   210 

   211     error := [:msg |

   212                 exceptionalValue isBlock ifTrue:[

   213                     ^ exceptionalValue valueWithOptionalArgument:'format error'

   214                 ] ifFalse:[

   215                     ^ exceptionalValue value

   216                 ].

   217              ].

   218 

   219     itemHandler := [:format |

   220         |input|

   221 

   222         input := len isNil ifTrue:[ inStream ] ifFalse:[ inStream next: len ].

   223 

   224         ( format = 'h' or:[ format = 'H' ]) ifTrue:[

   225             hour := Integer readFrom:input onError:[ error value:'invalid hour' ].

   226 

   227         ] ifFalse:[ ( format = 'u'  or:[ format = 'U']) ifTrue:[

   228             hour := Integer readFrom:input onError:[ error value:'invalid hour' ].

   229 

   230         ] ifFalse:[ ( format = 'm'  or:[ format = 'M' ]) ifTrue:[

   231             minute := Integer readFrom:input onError:[ error value:'invalid minute' ].

   232 

   233         ] ifFalse:[ ( format = 's'  or:[ format = 'S' ]) ifTrue:[

   234             second := Integer readFrom:input onError:[ error value:'invalid second' ].

   235 

   236         ] ifFalse:[ ( format = 'i'  or:[ format = 'I' ]) ifTrue:[

   237             millisecond := Integer readFrom:input onError:[ error value:'invalid millsecond' ].

   238 

   239         ] ifFalse:[ ( format = 'tz' ) ifTrue:[

   240             utcOffset := Timestamp utcOffsetFrom:input.

   241             utcOffset isNil ifTrue:[ error value:'invalid timezone' ]

   242         ] ifFalse:[ ( format = 'a' ) ifTrue:[

   243             s := (input next:2) asLowercase.

   244             s = 'am' ifTrue:[

   245                 (hour between:0 and:12) ifFalse:[ error value:'invalid hour' ]

   246             ] ifFalse:[

   247                 s = 'pm' ifTrue:[

   248                     (hour between:1 and:12) ifFalse:[ error value:'invalid hour' ].

   249                     hour := hour + 12.

   250                 ] ifFalse:[

   251                     error value:'invalid am/pm'

   252                 ]

   253             ]

   254 

   255         ] ifFalse:[

   256             error value:'unhandled format:',format

   257         ]]]]]]]

   258     ].

   259 

   260     hour := 0.

   261     minute := 0.

   262     second := 0.

   263     millisecond := 0.

   264     utcOffset := 0.

   265 

   266     inStream := aStringOrStream readStream.

   267     formatStream := formatString readStream.

   268 

   269     [formatStream atEnd] whileFalse:[

   270         fChar := formatStream next.

   271         fChar = Character space ifTrue:[

   272             inStream peek isSeparator ifFalse:[ error value: 'format error; space expcected' ].

   273             inStream skipSeparators.

   274         ] ifFalse:[

   275             fChar == $% ifTrue:[

   276                 len := nil.

   277                 (formatStream peek isDigit) ifTrue:[

   278                     len := Integer readFrom:formatStream onError:[ error value: 'format error; invalid length' ]

   279                 ].

   280                 (formatStream peek == $() ifTrue:[

   281                     formatStream next.

   282                     format := formatStream upTo:$).

   283                 ] ifFalse:[

   284                     (formatStream peek == ${) ifTrue:[

   285                         formatStream next.

   286                         format := formatStream upTo:$}.

   287                     ] ifFalse:[

   288                         (formatStream peek isLetter) ifTrue:[

   289                             format := formatStream nextAlphaNumericWord.

   290                         ] ifFalse:[

   291                             error value:'unhandled format:',formatStream peek

   292                         ]

   293                     ]

   294                 ].

   295                 itemHandler value:format.

   296             ] ifFalse:[

   297                 inStream peek = fChar ifFalse:[^ error value: 'format error; ',fChar,' expcected'].

   298                 inStream next.

   299             ]

   300         ].

   301     ].

   302 

   303     ^ (self 

   304         hours:(hour ? 0) minutes:(minute ? 0) seconds:(second ? 0) milliseconds:millisecond) 

   305             + utcOffset

   306 

   307     "

   308      Time readFrom:'13:11:06' format:'%h:%m:%s' language:nil onError:[self halt]

   309      Time readFrom:'131106' format:'%2h%2m%2s' language:nil onError:[self halt]

   310      Time readFrom:'7:30pm EST' format:'%u:%m%a %tz' language:#en onError:[self halt]

   311      Time readFrom:'7:30pm UTC' format:'%u:%m%a %tz' language:#en onError:[self halt]