-> operator

hashin_p has asked for the wisdom of the Perl Monks concerning the following question:

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Re: -> operator by moritz (Cardinal) on Nov 13, 2007 at 12:02 UTC
There are disambiguation rules, for example: If the `->` is followed by braces or brackets, it's a hash or array lookup Otherwise, if the LHS is a blessed reference, it's dispatched as a method call If the LHS is a package name, the RHS is interpreted as a sub and the first arg is the LHS (this is quasi identical to the previous case). I'm sure there are more rules, but in general it does what I mean (dwim) ;-)	[reply] [d/l]
Re^2: -> operator by Anonymous Monk on Nov 13, 2007 at 13:33 UTC
You can also do: `$subref->(@args);` [download]	[reply] [d/l]
Re^2: -> operator by chromatic (Archbishop) on Nov 13, 2007 at 16:50 UTC
If the LHS is a package name, the RHS is interpreted as a sub and the first arg is the LHS (this is quasi identical to the previous case). I think the word "method" is better than "sub" there, as method dispatch occurs in this case. (Use B::Concise and look for an op named `fetchmethod` or something similar.)	[reply] [d/l]
Re: -> operator by lupey (Monk) on Nov 13, 2007 at 16:06 UTC
The description of the arrow operator is found here	[reply]
Re: -> operator by tuxz0r (Pilgrim) on Nov 13, 2007 at 16:24 UTC
I'm not sure what your background is, but a good reference on language grammars for interpreters and compilers is Principles of Compiler Design (the dragon book). This gives a really good description of different types of langauge parsing and how they work. I can't find a good reference on the Perl language grammar (anyone?); but it's somewhere to start. --- `echo S 1 [ Y V U \| perl -ane 'print reverse map { $_ = chr(ord($_)-1) } @F;'` Warning: Any code posted by tuxz0r is untested, unless otherwise stated, and is used at your own risk.	[reply]
Re: -> operator by naikonta (Curate) on Nov 14, 2007 at 01:38 UTC
Basically, Perl has its own way to interprete the syntax, for example to distinct the same operators or functions usage, based on some contexts. Parsing things such as `$scalar->[0]` or `$scalar->{key}`, or even `$scalar->method` is straightforward and will Do What I (programmer) Mean. Please see perlref for detail. wont it get confused.Wont there be any ambiguity? In case of ambiguity, Perl will try its best to Do What I (programmer) Really Mean. If it gets confused though, it may warn me, or I can make it confess to show more detail what or where it gets confused. This helps me to see that my code might not steadily represent what I mean. And if it really doesn't have any idea on some piece of code, or refuses to look further, it will die and let me informed that what and where in my code some part just doesn't make sense to it. Open source softwares? Share and enjoy. Make profit from them if you can. Yet, share and enjoy!	[reply] [d/l] [select]