Delegates: Difference between revisions
→{{header|Phix}}
Line 2,025:
say "Delegate: "~$d.operation;</lang>
=={{header|Phix}}==
Phix is not object orientated, instead I would just use a routine_id for this sort of thing.<br>
I will admit that the whole concept of "no delegate/with one that does not implement" makes no sense whatsoever to me.<br>
While I've shown this using a single rid, you could of course hold an entire sequence of them or even better a dictionary and use named lookups for rids in that.
<lang Phix>enum OTHER, OPERATION
function operation(object o)
integer rid = o[OPERATION]
if rid!=NULL then
return call_func(rid,{})
end if
return "no implementation"
end function
function xthing()
return "default implementation"
end function
function newX()
return {1,routine_id("xthing"),2}
end function
function newY()
object res = newX()
res[OTHER] = "something else"
-- remove delegate:
res[OPERATION] = NULL
return res
end function
function zthing()
return "delegate implementation"
end function
function newZ()
object res = newX()
-- replace delegate:
res[OPERATION] = routine_id("zthing")
return res
end function
object x = newX(),
y = newY(),
z = newZ()
?operation(x)
?operation(y)
?operation(z)</lang>
{{out}}
<pre>
"default implementation"
"no implementation"
"delegate implementation"
</pre>
Obviously, you can explictly test for rid=NULL as shown, or remove that test and catch exceptions, ie:
<lang Phix>?operation(x)
try -- (since rid=NULL check commented out)
?operation(y)
catch e
?"oops, no implementation"
end try
?operation(z)</lang>
=={{header|PHP}}==
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