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Filename : cdesc-ARGF.ri
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U:RDoc::NormalClass[iI"	ARGF:ET@I"Object;To:RDoc::Markup::Document:@parts[o;;[aS:RDoc::Markup::Heading:
leveli:	textI"\ARGF and +ARGV+;To:RDoc::Markup::BlankLine�o:RDoc::Markup::Paragraph;[I"EThe \ARGF object works with the array at global variable +ARGV+ ;TI"Lto make <tt>$stdin</tt> and file streams available in the Ruby program:;T@o:RDoc::Markup::List:
@type:BULLET:@items[o:RDoc::Markup::ListItem:@label0;[	o;
;[I"D**ARGV** may be thought of as the <b>argument vector</b> array.;T@o;
;[I"CInitially, it contains the command-line arguments and options ;TI"*that are passed to the Ruby program; ;TI"3the program can modify that array as it likes.;T@o;;0;[	o;
;[I"D**ARGF** may be thought of as the <b>argument files</b> object.;T@o;
;[	I"CIt can access file streams and/or the <tt>$stdin</tt> stream, ;TI"'based on what it finds in +ARGV+. ;TI"9This provides a convenient way for the command line ;TI"3to specify streams for a Ruby program to read.;T@S;	;
i;I"Reading;T@o;
;[I"+\ARGF may read from _source_ streams, ;TI"Jwhich at any particular time are determined by the content of +ARGV+.;T@S;	;
i;I"Simplest Case;T@o;
;[I"VWhen the <i>very first</i> \ARGF read occurs with an empty +ARGV+ (<tt>[]</tt>), ;TI"#the source is <tt>$stdin</tt>:;T@o;;;;[o;;0;[o;
;[I"\File +t.rb+:;T@o:RDoc::Markup::Verbatim;[I"p ['ARGV', ARGV]
;TI" p ['ARGF.read', ARGF.read]
;T:@format0o;;0;[o;
;[I"Commands and outputs ;TI"B(see below for the content of files +foo.txt+ and +bar.txt+):;T@o;;[I"7$ echo "Open the pod bay doors, Hal." | ruby t.rb
;TI"["ARGV", []]
;TI"5["ARGF.read", "Open the pod bay doors, Hal.\n"]
;TI"
;TI"'$ cat foo.txt bar.txt | ruby t.rb
;TI"["ARGV", []]
;TI"A["ARGF.read", "Foo 0\nFoo 1\nBar 0\nBar 1\nBar 2\nBar 3\n"]
;T;0S;	;
i;I"About the Examples;T@o;
;[I"NMany examples here assume the existence of files +foo.txt+ and +bar.txt+:;T@o;;[
I"$ cat foo.txt
;TI"Foo 0
;TI"Foo 1
;TI"$ cat bar.txt
;TI"Bar 0
;TI"Bar 1
;TI"Bar 2
;TI"Bar 3
;T;0S;	;
i;I"Sources in +ARGV+;T@o;
;[I"RFor any \ARGF read _except_ the {simplest case}[rdoc-ref:ARGF@Simplest+Case] ;TI"T(that is, _except_ for the <i>very first</i> \ARGF read with an empty +ARGV+), ;TI"%the sources are found in +ARGV+.;T@o;
;[I"L\ARGF assumes that each element in array +ARGV+ is a potential source, ;TI"and is one of:;T@o;;;;[o;;0;[o;
;[I">The string path to a file that may be opened as a stream.;To;;0;[o;
;[I"@The character <tt>'-'</tt>, meaning stream <tt>$stdin</tt>.;T@o;
;[I"-Each element that is _not_ one of these ;TI"Eshould be removed from +ARGV+ before \ARGF accesses that source.;T@o;
;[I"In the following example:;T@o;;;;[o;;0;[o;
;[I"LFilepaths +foo.txt+ and +bar.txt+ may be retained as potential sources.;To;;0;[o;
;[I"DOptions <tt>--xyzzy</tt> and <tt>--mojo</tt> should be removed.;T@o;
;[I"
Example:;T@o;;;;[o;;0;[o;
;[I"\File +t.rb+:;T@o;;[I"D# Print arguments (and options, if any) found on command line.
;TI"p ['ARGV', ARGV]
;T;0o;;0;[o;
;[I"Command and output:;T@o;;[I"0$ ruby t.rb --xyzzy --mojo foo.txt bar.txt
;TI";["ARGV", ["--xyzzy", "--mojo", "foo.txt", "bar.txt"]]
;T;0o;
;[I"K\ARGF's stream access considers the elements of +ARGV+, left to right:;T@o;;;;[o;;0;[o;
;[I"\File +t.rb+:;T@o;;[I"p "ARGV: #{ARGV}"
;TI"Jp "Line: #{ARGF.read}" # Read everything from all specified streams.
;T;0o;;0;[o;
;[I"Command and output:;T@o;;[I"!$ ruby t.rb foo.txt bar.txt
;TI"("ARGV: [\"foo.txt\", \"bar.txt\"]"
;TI"8"Read: Foo 0\nFoo 1\nBar 0\nBar 1\nBar 2\nBar 3\n"
;T;0o;
;[I"7Because the value at +ARGV+ is an ordinary array, ;TI"Dyou can manipulate it to control which sources \ARGF considers:;T@o;;;;[o;;0;[o;
;[I"\If you remove an element from +ARGV+, \ARGF will not consider the corresponding source.;To;;0;[o;
;[I"SIf you add an element to +ARGV+, \ARGF will consider the corresponding source.;T@o;
;[I"REach element in +ARGV+ is removed when its corresponding source is accessed; ;TI"=when all sources have been accessed, the array is empty:;T@o;;;;[o;;0;[o;
;[I"\File +t.rb+:;T@o;;[	I"$until ARGV.empty? && ARGF.eof?
;TI"  p "ARGV: #{ARGV}"
;TI"O  p "Line: #{ARGF.readline}" # Read each line from each specified stream.
;TI"	end
;T;0o;;0;[o;
;[I"Command and output:;T@o;;[I"!$ ruby t.rb foo.txt bar.txt
;TI"("ARGV: [\"foo.txt\", \"bar.txt\"]"
;TI""Line: Foo 0\n"
;TI""ARGV: [\"bar.txt\"]"
;TI""Line: Foo 1\n"
;TI""ARGV: [\"bar.txt\"]"
;TI""Line: Bar 0\n"
;TI""ARGV: []"
;TI""Line: Bar 1\n"
;TI""ARGV: []"
;TI""Line: Bar 2\n"
;TI""ARGV: []"
;TI""Line: Bar 3\n"
;T;0S;	;
i	;I"Filepaths in +ARGV+;T@o;
;[I"RThe +ARGV+ array may contain filepaths the specify sources for \ARGF reading.;T@o;
;[I"IThis program prints what it reads from files at the paths specified ;TI"on the command line:;T@o;;;;[o;;0;[o;
;[I"\File +t.rb+:;T@o;;[I"p ['ARGV', ARGV]
;TI"># Read and print all content from the specified sources.
;TI" p ['ARGF.read', ARGF.read]
;T;0o;;0;[o;
;[I"Command and output:;T@o;;[I"!$ ruby t.rb foo.txt bar.txt
;TI"!["ARGV", [foo.txt, bar.txt]
;TI"A["ARGF.read", "Foo 0\nFoo 1\nBar 0\nBar 1\nBar 2\nBar 3\n"]
;T;0S;	;
i	;I")Specifying <tt>$stdin</tt> in +ARGV+;T@o;
;[I"PTo specify stream <tt>$stdin</tt> in +ARGV+, us the character <tt>'-'</tt>:;T@o;;;;[o;;0;[o;
;[I"\File +t.rb+:;T@o;;[I"p ['ARGV', ARGV]
;TI" p ['ARGF.read', ARGF.read]
;T;0o;;0;[o;
;[I"Command and output:;T@o;;[I"9$ echo "Open the pod bay doors, Hal." | ruby t.rb -
;TI"["ARGV", ["-"]]
;TI"5["ARGF.read", "Open the pod bay doors, Hal.\n"]
;T;0o;
;[I"PWhen no character <tt>'-'</tt> is given, stream <tt>$stdin</tt> is ignored ;TI"(exception: ;TI"Qsee {Specifying $stdin in ARGV}[rdoc-ref:ARGF@Specifying+-24stdin+in+ARGV]):;T@o;;;;[o;;0;[o;
;[I"Command and output:;T@o;;[I"G$ echo "Open the pod bay doors, Hal." | ruby t.rb foo.txt bar.txt
;TI"("ARGV: [\"foo.txt\", \"bar.txt\"]"
;TI"8"Read: Foo 0\nFoo 1\nBar 0\nBar 1\nBar 2\nBar 3\n"
;T;0S;	;
i	;I"'Mixtures and Repetitions in +ARGV+;T@o;
;[I"FFor an \ARGF reader, +ARGV+ may contain any mixture of filepaths ;TI"7and character <tt>'-'</tt>, including repetitions.;T@S;	;
i	;I"Modifications to +ARGV+;T@o;
;[I"NThe running Ruby program may make any modifications to the +ARGV+ array; ;TI"7the current value of +ARGV+ affects \ARGF reading.;T@S;	;
i	;I"Empty +ARGV+;T@o;
;[I"DFor an empty +ARGV+, an \ARGF read method either returns +nil+ ;TI">or raises an exception, depending on the specific method.;T@S;	;
i;I"More Read Methods;T@o;
;[	I"FAs seen above, method ARGF#read reads the content of all sources ;TI"into a single string. ;TI"DOther \ARGF methods provide other ways to access that content; ;TI"these include:;T@o;;;;[
o;;0;[o;
;[I"2Byte access: #each_byte, #getbyte, #readbyte.;To;;0;[o;
;[I"4Character access: #each_char, #getc, #readchar.;To;;0;[o;
;[I"'Codepoint access: #each_codepoint.;To;;0;[o;
;[I";Line access: #each_line, #gets, #readline, #readlines.;To;;0;[o;
;[I"8Source access: #read, #read_nonblock, #readpartial.;T@S;	;
i;I"About \Enumerable;T@o;
;[I"'\ARGF includes module Enumerable. ;TI"\Virtually all methods in \Enumerable call method <tt>#each</tt> in the including class.;T@o;
;[	I"O<b>Note well</b>: In \ARGF, method #each returns data from the _sources_, ;TI"_not_ from +ARGV+; ;TI"_therefore, for example, <tt>ARGF#entries</tt> returns an array of lines from the sources, ;TI"-not an array of the strings from +ARGV+:;T@o;;;;[o;;0;[o;
;[I"\File +t.rb+:;T@o;;[I"p ['ARGV', ARGV]
;TI"&p ['ARGF.entries', ARGF.entries]
;T;0o;;0;[o;
;[I"Command and output:;T@o;;[I"!$ ruby t.rb foo.txt bar.txt
;TI"&["ARGV", ["foo.txt", "bar.txt"]]
;TI"Z["ARGF.entries", ["Foo 0\n", "Foo 1\n", "Bar 0\n", "Bar 1\n", "Bar 2\n", "Bar 3\n"]]
;T;0S;	;
i;I"Writing;T@o;
;[I"*If <i>inplace mode</i> is in effect, ;TI"(\ARGF may write to target streams, ;TI"Hwhich at any particular time are determined by the content of ARGV.;T@o;
;[I" Methods about inplace mode:;T@o;;;;[o;;0;[o;
;[I"#inplace_mode;To;;0;[o;
;[I"#inplace_mode=;To;;0;[o;
;[I"#to_write_io;T@o;
;[I"Methods for writing:;T@o;;;;[
o;;0;[o;
;[I"#print;To;;0;[o;
;[I"#printf;To;;0;[o;
;[I"
#putc;To;;0;[o;
;[I"
#puts;To;;0;[o;
;[I"#write;T:
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