C standard for initializations

[Niket K. Patwardhan]

Date:           Mon, 15 Jul 85 12:33:31 PDT
From:           Niket K. Patwardhan <niket>
To:             info-c
Subject:        C standard on initialization.

I would like this to get transferred to the C standards group as well as see
comments on this proposal.

It has always seemed to me extremely lame that C has no way of specifying that
a particular value is to be repeated N times, without actually typing out the
value N times. Although the draft standard permits initialization of
sub-aggregates via some pretty fancy grouping, it still says nothing about
duplicated values. The only practical way of initializing a large data
structure to something other than all NULLs is to actually write some code to
do it. What I would like to see is this

<initializer> ::=
		<assignment-expression>
		{ <initializer-list> }
		<constant-expression> { <initializer-list> }
		{ <initializer-list>, }

If the grammar is too hard to parse, or too unnatural, 
the constant expression can follow the initializer list in braces.
The  semantics is as follows:

constant-expression has to evaluate to a positive integer.
<constant-expression> { <initializer-list> }  is equivalent to
{ <initializer-list> } , { <initializer-list> } , ......  the right number of
times.


or

{ <initializer-list>, <initializer-list>,....... }

or some variation thereof.


On second thought the post-fix constant seems more natural, it having been
often used in documentation with the constant being a superscript.

I would consider a scheme that allowed a single constant to be repeated
insufficient. It is necessary that patterns can be specified as occurring
N times.