string's metatable?
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- Subject: string's metatable?
- From: PA <petite.abeille@...>
- Date: 2005年8月20日 12:55:54 +0200
Hello,
Using Lua 5.1 (work6).
Is the string's metatable here to stay? Can I confidently convert from
'string.len( aString )' to 'aString:len()' syntax?
If the string's metatable is a permanent feature, what is the
recommended way to add new functions to it?
For illustration purpose, lets assume I have a 'startsWith' method
which returns true or false if a given string starts with a given
prefix:
local StartsWith = function( self, aPrefix )
if aPrefix ~= nil then
if aPrefix == string.sub( self, 1, string.len( aPrefix
) ) then
return true
end
end
return false
end
How do I hook that up with the string's metatable?
Should I directly add it to the metatable __index?
local aString = "Content-Type"
local aMetaIndex = getmetatable( aString ).__index
aMetaIndex.startsWith = StartsWith
print( aString:startsWith( "Content" ) )
> true
Alternatives?
Finally, should the metatable be available to string literals?
"aString":lower()
lua: TestString.lua:106: attempt to call a nil value
stack traceback:
TestString.lua:106: in main chunk
[C]: ?
print( "aString":lower() )
lua: TestString.lua:106: ')' expected near ':'
TIA!
Cheers
--
PA, Onnay Equitursay
http://alt.textdrive.com/