Re: Are Associative Arrays unique to Perl?

here follows a long quote from the man page of "bs", "a remote
descendant of BASIC and SNOBOL4 with some C language added" (another
quote from bs(1)), that Hewlett-Packard ships with every copy of HP-UX


i make this post 'cause i'm curious about this "bs" thing, and i'd
like to know about its roots, uses, and most of all, why it is in the
HP-UX distribution!


ciao
                                                                                                                                gb
<-------------------------------------------------------------------->
Tables
    table(name, size)
                                  A table in bs is an associatively accessed,
                                  single- dimension array. ``Subscripts'' (called
                                  keys) are strings (numbers are converted). The
                                  name argument must be a bs variable name (passed
                                  as a string). The size argument sets the minimum
                                  number of elements to be allocated. bs prints an
                                  error message and stops on table overflow. The
                                  result of table is name.


    item(name, i)
    key()


                                  The item function accesses table elements
                                  sequentially (in normal use, there is no orderly
                                  progression of key values). Where the item
                                  function accesses values, the key function
                                  accesses the ``subscript'' of the previous item
                                  call. It fails (or in the absence of an
                                  interrogate operator, returns null) if there was
                                  no valid subscript for the previous item call.
                                  The name argument should not be quoted. Since
                                  exact table sizes are not defined, the
                                  interrogation operator should be used to detect
                                  end-of-table; for example:


                                            table("t", 100)
                                                    ...
                                            # If word contains "party", the following
                                            # expression adds one to the count of that
                                            # word:


                                            ++t[word]
                                                    ...
                                            # To print out the the key/value pairs:
                                            for i = 0, ?(s = item(t, i)), ++i if key() put = key()_":"_s


                                  If the interrogation operator is not used, the
                                  result of item is null if there are no further
                                  elements in the table. Null is, however, a legal
                                  ``subscript''.


    iskey(name, word)
                                  iskey tests whether the key word exists in the
                                  table name and returns one for true, zero for
                                  false.
[bs goes way back to the 5th or 6th edition of research Unix. Smells to me
like one of Ken Thompson's weekend hacks. -John]


--

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