Optional parameters: Difference between revisions
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(→{{header|Python}}: See the Python entry in Named Arguments for a more comprehensive description of Python function parameters and call arguments.) |
(add E example) |
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CL-USER> (sort-table *data* :ordering (lambda (a b) (> (length a) (length b)))) |
CL-USER> (sort-table *data* :ordering (lambda (a b) (> (length a) (length b)))) |
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(("zap" "zip" "Zot") ("a" "b" "c") ("" "q" "z"))</lang> |
(("zap" "zip" "Zot") ("a" "b" "c") ("" "q" "z"))</lang> |
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=={{header|E}}== |
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In E, as in Java and Smalltalk, optional parameters are defined as different methods with the same base name. Methods are distinguished by name (''verb'') and number of parameters (''arity''). |
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<lang e>def defaultOrdering(a, b) { return a.op__cmp(b) } |
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def sort { |
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to run(table) { |
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return sort(table, 0, false, defaultOrdering) |
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} |
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to run(table, column) { |
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return sort(table, column, false, defaultOrdering) |
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} |
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to run(table, column, reverse) { |
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return sort(table, column, reverse, defaultOrdering) |
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} |
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to run(table :List[List[String]], column :int, reverse :boolean, ordering) { |
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return table.sort(fn a, b { |
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def ord := ordering(a[column], b[column]) |
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if (reverse) { -ord } else { ord } |
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}) |
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} |
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}</lang> |
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Named parameters are not builtin, but map-patterns may be used as a substitute. (TODO: Example of this) [[Category:E examples needing attention]] |
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=={{header|Fortran}}== |
=={{header|Fortran}}== |
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