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| Both sides previous revision Previous revision Next revision | Previous revision Next revision Both sides next revision | ||
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complexvalues [2019/01/04 16:38] christian [Using Values] |
complexvalues [2019/01/04 16:56] christian [Using Values] |
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| Line 38: | Line 38: | ||
| </ | </ | ||
| - | Withit | + | With it you can: |
| * create a value with <code smalltalk> | * create a value with <code smalltalk> | ||
| * ask for its parts <code smalltalk> | * ask for its parts <code smalltalk> | ||
| Line 80: | Line 80: | ||
| The variables are set all at once by an initalizing method which has all initial values as parameters. | The variables are set all at once by an initalizing method which has all initial values as parameters. | ||
| The object becomes immutable after initialization and all instance variables are effectively constants. | The object becomes immutable after initialization and all instance variables are effectively constants. | ||
| + | |||
| + | The parameter names are the concatenated name and its class. This prevents name clashes, is systematic and still readable. | ||
| <code smalltalk> | <code smalltalk> | ||
| - | Person>> | + | Person>> |
| - | name := aString. | + | name := nameString. |
| - | sex := aSymbol. | + | sex := sexSymbol. |
| - | birthday := aDate. | + | birthday := birthdayDate. |
| self beImmutable | self beImmutable | ||
| </ | </ | ||
| Line 92: | Line 94: | ||
| <code smalltalk> | <code smalltalk> | ||
| - | Person class>> | + | Person class>> |
| | inst | | | inst | | ||
| inst := self new. | inst := self new. | ||
| - | inst initializeName: | + | inst initializeName: |
| ^inst | ^inst | ||
| </ | </ | ||
| Line 115: | Line 117: | ||
| < | < | ||
| < | < | ||
| - | < | + | < |
| </ | </ | ||
| === Defaults === | === Defaults === | ||
| - | The simple values above are not very interesting. But when you define defaults for some of the variables, Values become more useful | + | The simple values above are not very interesting. But when you define defaults for some of the variables, Values become more useful. Lets add a nickname to the specification: |
| + | |||
| + | <code smalltalk> | ||
| + | Person class>> | ||
| + | < | ||
| + | < | ||
| + | < | ||
| + | < | ||
| + | </ | ||
| + | |||
| + | After generating code with: | ||
| + | <code smalltalk> | ||
| + | our example responds to #nickname : | ||
| + | |||
| + | <code smalltalk> | ||
| + | Person example nickname | ||
| + | </ | ||
| + | |||
| + | and there is a new constructor available: | ||
| + | <code smalltalk> | ||
| + | Person class>> | ||
| + | </ | ||
| + | |||
| + | Now you can specify a nickname: | ||
| + | <code smalltalk> | ||
| + | Person name: ' | ||
| + | </ | ||
| + | |||
| + | If you use the same parameter as the default, it is ignored | ||
| + | <code smalltalk> | ||
| + | Person name: ' | ||
| + | </ | ||
| + | because it is equal to | ||
| + | <code smalltalk> | ||
| + | Person name: ' | ||
| + | </ | ||
| ==== Get it ==== | ==== Get it ==== | ||