Hier werden die Unterschiede zwischen zwei Versionen angezeigt.
Beide Seiten der vorigen Revision Vorhergehende Überarbeitung Nächste Überarbeitung | Vorhergehende Überarbeitung | ||
becki:linux:lua [2016-03-03 10:21] becki [C-style ?-operator equivalent] |
becki:linux:lua [2023-12-27 13:57] (aktuell) becki [Classes and Objects] |
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[[http://kripken.github.io/lua.vm.js/script_example.html|lua.vm.js]] thanks to asm.js | [[http://kripken.github.io/lua.vm.js/script_example.html|lua.vm.js]] thanks to asm.js | ||
+ | |||
+ | ==== Lua for Java/Android == | ||
+ | |||
+ | [[https://sourceforge.net/projects/luaj/|Luaj]], seen at [[https://github.com/M66B/XPrivacyLua/blob/master/README.md|XPrivacyLua]] | ||
===== C-style ?-operator equivalent == | ===== C-style ?-operator equivalent == | ||
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</code> | </code> | ||
- | <note warning>Take care if b can become ''nil'' or ''false''. In this case the equivalent doesn't work.Instead use:</note> | + | <note warning>Take care if b can become ''nil'' or ''false''. In this case the equivalent doesn't work. Instead use:</note> |
<code lua> | <code lua> | ||
if a then d=b else d=c end | if a then d=b else d=c end | ||
</code> | </code> | ||
+ | |||
+ | ===== Default values for missing arguments == | ||
+ | |||
+ | <code lua> | ||
+ | function foo(a) | ||
+ | a= a or "defaultvalue" | ||
+ | end | ||
+ | </code> | ||
+ | |||
+ | Take care, if ''false'' is a valid value, instead use: | ||
+ | |||
+ | <code lua> | ||
+ | function foo(a) | ||
+ | if a==nil then a="defaultvalue" end | ||
+ | end | ||
+ | </code> | ||
+ | |||
===== Difference between nil and no value == | ===== Difference between nil and no value == | ||
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===== Classes and Objects == | ===== Classes and Objects == | ||
+ | |||
+ | See also projects/accounting/sbaccimport which has since rev 482:c85c255f1870 classes with inheritance where the constructor new() is a class method and can therefore be reused in child classes similar to PIL capter 21 | ||
==== Classes as Object templates == | ==== Classes as Object templates == | ||
<code lua> | <code lua> | ||
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- ''"l"'' as arg for ''read()'' is the default, it can be omitted | - ''"l"'' as arg for ''read()'' is the default, it can be omitted | ||
- ''file:lines()'' and ''io.lines()'' accept the same format args as ''read()''. (Tested. Nowhere found in docu). Thus you could read a file eg chunk by chunk as well. | - ''file:lines()'' and ''io.lines()'' accept the same format args as ''read()''. (Tested. Nowhere found in docu). Thus you could read a file eg chunk by chunk as well. | ||
+ | - io.lines() without arguments returns an iterater wich returns stdin line by line | ||
+ | ==== Load CSV-like files == | ||
+ | |||
+ | <code lua> | ||
+ | #!/usr/bin/lua | ||
+ | local separator=":" | ||
+ | for line in io.lines() do | ||
+ | print(line) | ||
+ | for cell in line:gmatch("[^"..separator.."]+") do | ||
+ | print("", cell) | ||
+ | end | ||
+ | end | ||
+ | </code> | ||
===== Includes and Modules == | ===== Includes and Modules == | ||
==== Include == | ==== Include == |