Difference between revisions of "Assert"
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'''Available since:''' Gideros 2011.6<br/> | '''Available since:''' Gideros 2011.6<br/> | ||
| + | '''Class:''' [[(global)]]<br/> | ||
| + | |||
=== Description === | === Description === | ||
| − | Issues an error when the value of its argument v is false (i.e. | + | Issues an error when the value of its argument ''v'' is false (i.e.: nil or false), otherwise returns all its arguments. |
| − | < | + | <syntaxhighlight lang="lua"> |
| − | + | assert(v,message) | |
| − | </ | + | </syntaxhighlight> |
| − | '''v''': (any) expression/function to assert | + | |
| + | ''message'' is an error message, when absent it defaults to "assertion failed!". | ||
| + | |||
| + | === Parameters === | ||
| + | '''v''': (any) expression/function to assert<br/> | ||
'''message''': (string) error message if assert fails '''optional'''<br/> | '''message''': (string) error message if assert fails '''optional'''<br/> | ||
| + | |||
| + | === Examples === | ||
| + | '''Checks if a texture is valid''' | ||
| + | <syntaxhighlight lang="lua"> | ||
| + | function isValidTexture() | ||
| + | local result, msg = assert(Texture.new(texturepath), "file is not recognised") | ||
| + | print(result, msg) | ||
| + | return result | ||
| + | end | ||
| + | |||
| + | function showTexture() | ||
| + | if isValidTexture() then bmp = Bitmap.new(Texture.new(texturepath)) end | ||
| + | end | ||
| + | </syntaxhighlight> | ||
| + | |||
| + | '''Checks if is of type ''number''''' | ||
| + | <syntaxhighlight lang="lua"> | ||
| + | local value = 12 --> 12 | ||
| + | --local value = "hello" --> *** Friction must be a number *** | ||
| + | assert(type(value) == 'number', "*** Friction must be a number ***") | ||
| + | </syntaxhighlight> | ||
| + | |||
| + | === See also === | ||
| + | '''[[Pcall]]''' | ||
| + | |||
| + | {{(global)}} | ||
Latest revision as of 17:23, 12 July 2023
Available since: Gideros 2011.6
Class: (global)
Description
Issues an error when the value of its argument v is false (i.e.: nil or false), otherwise returns all its arguments.
assert(v,message)
message is an error message, when absent it defaults to "assertion failed!".
Parameters
v: (any) expression/function to assert
message: (string) error message if assert fails optional
Examples
Checks if a texture is valid
function isValidTexture()
local result, msg = assert(Texture.new(texturepath), "file is not recognised")
print(result, msg)
return result
end
function showTexture()
if isValidTexture() then bmp = Bitmap.new(Texture.new(texturepath)) end
end
Checks if is of type number
local value = 12 --> 12
--local value = "hello" --> *** Friction must be a number ***
assert(type(value) == 'number', "*** Friction must be a number ***")
See also
