Difference between revisions of "Assert"

(added example)
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=== Description ===
 
=== Description ===
Issues an error when the value of its argument v is false (i.e., nil or false); otherwise, returns all its arguments. message is an error message; when absent, it defaults to "assertion failed!"
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Issues an error when the value of its argument ''v'' is false (i.e., nil or false), otherwise returns all its arguments.
 
<source lang="lua">
 
<source lang="lua">
 
assert(v,message)
 
assert(v,message)
 
</source>
 
</source>
 +
 +
''message'' is an error message, when absent it defaults to "assertion failed!".
  
 
=== Parameters ===
 
=== Parameters ===
 
'''v''': (any) expression/function to assert<br/>
 
'''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/>
 +
 +
=== Example ===
 +
'''Checks if a texture is valid'''
 +
<source lang="lua">
 +
function isValidTexture()
 +
local result, msg = assert(Texture.new(texturepath), "file is not recognised")
 +
print(result, msg)
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return result
 +
end
 +
 +
function showTexture()
 +
if isValidTexture() then bmp = Bitmap.new(Texture.new(texturepath)) end
 +
end
 +
</source>
  
 
{{(global)}}
 
{{(global)}}

Revision as of 09:58, 2 March 2021

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

Example

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