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Postings from December 2001
Dan Sugalski wrote: > > 'Kay, here's the preliminary assembly-level docs for keys, which is how > we're going to be accessing entries in aggregates. > > --------------Snip here--------------- > =head2 Key operations > > Keys are used to get access to individual elements of an aggregate > variable. This is done to allow for opaque, packed, and > multidimensional aggregate types. > > A key entry may be an integer, string, or PMC. Integers are used for > array lookups, strings for hash lookups, and PMCs for either. > > =over 4 > > =item new_key Sx The fact that the S registers are in fact generic struct registers is not evident from outside the internal code. For those of us implementing instructions, it might be useful to explicitly cast values like $1 to the correct type, in order to make sure we recognize this. The following code came up frequently when writing the key() functions that Dan enumerated int his file... key_inc(interpreter, $1, $2); Explicitly casting $1 to (KEY*) helps reinforce this fact, eliminates a compile-time warning, and doesn't cost any runtime penalty. -- Jeff <jgoff@speakeasy.net>Thread Previous