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From: plph@caen.engin.umich.edu (Mark Montague)
Newsgroups: comp.compilers
Subject: Re: Defining polymorphism vs. overloading
Keywords: design, polymorphism
Message-ID: <4c98dcd0b.001a92c@caen.engin.umich.edu>
Date: 4 Sep 90 01:09:04 GMT
References: <9008310419.AA06194@karakorum.berkeley.edu>
Sender: compilers-sender@esegue.segue.boston.ma.us
Reply-To: plph@caen.engin.umich.edu (Mark Montague)
Organization: University of Michigan Engineering, Ann Arbor
Lines: 26
Approved: compilers@esegue.segue.boston.ma.us

Are the square braces in C polymorphic or overloaded?  Which term should be
used?  I am no expert, but my personal opinion is NEITHER.  As a programmer
who has just begun delving into the mysteries of compiler construction, I
prefer to think of the square braces as a SHORTHAND NOTATION which is expanded
by the preprocessor (even though the preprocessor doesn't).  So I imagine that
every expression of the form

		myarray[index]

is silently transformed into

		*(myarray+index)

before the compiler even sees it.  Even though it probably doesn't happen
this way for most compilers, this fictional device lets me ignore questions
of polymorphism and operator overloading in a non-object-oriented language
such as C.

Mark Montague
plph@caen.engin.umich.edu
[In the C compilers I've seen subscripts are turned into the intermediate code
equivalent of *(a+b) very early in the compiler, typically as the intermediate
form is being built. -John]
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