IO::ScalarArray - IO:: interface for reading/writing an array of scalars

Eryq (eryq@zeegee.com). President, ZeeGee Software Inc (http://www.zeegee.com).

Dianne Skoll (dfs@roaringpenguin.com).

Copyright (c) 1997 Erik (Eryq) Dorfman, ZeeGee Software, Inc. All rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. perl v5.38.2 2024-07-31 IO::ScalarArray(3pm)

This class is part of the IO::Stringy distribution; see IO::Stringy for change log and general information. The IO::ScalarArray class implements objects which behave just like IO::Handle (or FileHandle) objects, except that you may use them to write to (or read from) arrays of scalars. Logically, an array of scalars defines an in-core "file" whose contents are the concatenation of the scalars in the array. The handles created by this class are automatically "tiehandle"d (though please see "WARNINGS" for information relevant to your Perl version). For writing large amounts of data with individual print() statements, this class is likely to be more efficient than IO::Scalar. Basically, this: my @a; $AH = new IO::ScalarArray \@a; $AH->print("Hel", "lo, "); ### OO style $AH->print("world!\n"); ### ditto Or this: my @a; $AH = new IO::ScalarArray \@a; print $AH "Hel", "lo, "; ### non-OO style print $AH "world!\n"; ### ditto Causes @a to be set to the following array of 3 strings: ( "Hel" , "lo, " , "world!\n" ) See IO::Scalar and compare with this class.

IO::ScalarArray - IO:: interface for reading/writing an array of scalars

Construction new [ARGS...] Classmethod. Return a new, unattached array handle. If any arguments are given, they're sent to open(). open [ARRAYREF] Instancemethod. Open the array handle on a new array, pointed to by ARRAYREF. If no ARRAYREF is given, a "private" array is created to hold the file data. Returns the self object on success, undefined on error. opened Instancemethod. Is the array handle opened on something? close Instancemethod. Disassociate the array handle from its underlying array. Done automatically on destroy. Inputandoutput flush Instancemethod. No-op, provided for OO compatibility. fileno Instancemethod. No-op, returns undef getc Instancemethod. Return the next character, or undef if none remain. This does a read(1), which is somewhat costly. getline Instancemethod. Return the next line, or undef on end of data. Can safely be called in an array context. Currently, lines are delimited by "\n". getlines Instancemethod. Get all remaining lines. It will croak() if accidentally called in a scalar context. print ARGS... Instancemethod. Print ARGS to the underlying array. Currently, this always causes a "seek to the end of the array" and generates a new array entry. This may change in the future. read BUF, NBYTES, [OFFSET]; Instancemethod. Read some bytes from the array. Returns the number of bytes actually read, 0 on end-of-file, undef on error. write BUF, NBYTES, [OFFSET]; Instancemethod. Write some bytes into the array. Seeking/tellingandotherattributes autoflush Instancemethod. No-op, provided for OO compatibility. binmode Instancemethod. No-op, provided for OO compatibility. clearerr Instancemethod. Clear the error and EOF flags. A no-op. eof Instancemethod. Are we at end of file? seek POS,WHENCE Instancemethod. Seek to a given position in the stream. Only a WHENCE of 0 (SEEK_SET) is supported. tell Instancemethod. Return the current position in the stream, as a numeric offset. setpos POS Instancemethod. Seek to a given position in the array, using the opaque getpos() value. Don't expect this to be a number. getpos Instancemethod. Return the current position in the array, as an opaque value. Don't expect this to be a number. aref Instancemethod. Return a reference to the underlying array.

Perform I/O on strings, using the basic OO interface... use IO::ScalarArray; @data = ("My mes", "sage:\n"); ### Open a handle on an array, and append to it: $AH = new IO::ScalarArray \@data; $AH->print("Hello"); $AH->print(", world!\nBye now!\n"); print "The array is now: ", @data, "\n"; ### Open a handle on an array, read it line-by-line, then close it: $AH = new IO::ScalarArray \@data; while (defined($_ = $AH->getline)) { print "Got line: $_"; } $AH->close; ### Open a handle on an array, and slurp in all the lines: $AH = new IO::ScalarArray \@data; print "All lines:\n", $AH->getlines; ### Get the current position (either of two ways): $pos = $AH->getpos; $offset = $AH->tell; ### Set the current position (either of two ways): $AH->setpos($pos); $AH->seek($offset, 0); ### Open an anonymous temporary array: $AH = new IO::ScalarArray; $AH->print("Hi there!"); print "I printed: ", @{$AH->aref}, "\n"; ### get at value Don't like OO for your I/O? No problem. Thanks to the magic of an invisible tie(), the following now works out of the box, just as it does with IO::Handle: use IO::ScalarArray; @data = ("My mes", "sage:\n"); ### Open a handle on an array, and append to it: $AH = new IO::ScalarArray \@data; print $AH "Hello"; print $AH ", world!\nBye now!\n"; print "The array is now: ", @data, "\n"; ### Open a handle on a string, read it line-by-line, then close it: $AH = new IO::ScalarArray \@data; while (<$AH>) { print "Got line: $_"; } close $AH; ### Open a handle on a string, and slurp in all the lines: $AH = new IO::ScalarArray \@data; print "All lines:\n", <$AH>; ### Get the current position (WARNING: requires 5.6): $offset = tell $AH; ### Set the current position (WARNING: requires 5.6): seek $AH, $offset, 0; ### Open an anonymous temporary scalar: $AH = new IO::ScalarArray; print $AH "Hi there!"; print "I printed: ", @{$AH->aref}, "\n"; ### get at value And for you folks with 1.x code out there: the old tie() style still works, though this is unnecessaryanddeprecated: use IO::ScalarArray; ### Writing to a scalar... my @a; tie *OUT, 'IO::ScalarArray', \@a; print OUT "line 1\nline 2\n", "line 3\n"; print "Array is now: ", @a, "\n" ### Reading and writing an anonymous scalar... tie *OUT, 'IO::ScalarArray'; print OUT "line 1\nline 2\n", "line 3\n"; tied(OUT)->seek(0,0); while (<OUT>) { print "Got line: ", $_; }