class ARGF
ARGF
is a stream designed for use in scripts that process files given as command-line arguments or passed in via STDIN.
The arguments passed to your script are stored in the ARGV
Array
, one argument per element. ARGF
assumes that any arguments that aren’t filenames have been removed from ARGV
. For example:
$ ruby argf.rb --verbose file1 file2 ARGV #=> ["--verbose", "file1", "file2"] option = ARGV.shift #=> "--verbose" ARGV #=> ["file1", "file2"]
You can now use ARGF
to work with a concatenation of each of these named files. For instance, ARGF.read
will return the contents of file1 followed by the contents of file2.
After a file in ARGV
has been read ARGF
removes it from the Array
. Thus, after all files have been read ARGV
will be empty.
You can manipulate ARGV
yourself to control what ARGF
operates on. If you remove a file from ARGV
, it is ignored by ARGF
; if you add files to ARGV
, they are treated as if they were named on the command line. For example:
ARGV.replace ["file1"] ARGF.readlines # Returns the contents of file1 as an Array ARGV #=> [] ARGV.replace ["file2", "file3"] ARGF.read # Returns the contents of file2 and file3
If ARGV
is empty, ARGF
acts as if it contained "-"
that makes ARGF
read from STDIN, i.e. the data piped or typed to your script. For example:
$ echo "glark" | ruby -e 'p ARGF.read' "glark\n" $ echo Glark > file1 $ echo "glark" | ruby -e 'p ARGF.read' -- - file1 "glark\nGlark\n"
Public Instance Methods
Returns the ARGV
array, which contains the arguments passed to your script, one per element.
For example:
$ ruby argf.rb -v glark.txt ARGF.argv #=> ["-v", "glark.txt"]
static VALUE argf_argv(VALUE argf) { return ARGF.argv; }
Puts ARGF
into binary mode. Once a stream is in binary mode, it cannot be reset to non-binary mode. This option has the following effects:
-
Newline conversion is disabled.
-
Encoding
conversion is disabled. -
Content is treated as ASCII-8BIT.
static VALUE argf_binmode_m(VALUE argf) { ARGF.binmode = 1; next_argv(); ARGF_FORWARD(0, 0); rb_io_ascii8bit_binmode(ARGF.current_file); return argf; }
Returns true if ARGF
is being read in binary mode; false otherwise. To enable binary mode use ARGF.binmode
.
For example:
ARGF.binmode? #=> false ARGF.binmode ARGF.binmode? #=> true
static VALUE argf_binmode_p(VALUE argf) { return RBOOL(ARGF.binmode); }
Closes the current file and skips to the next file in ARGV. If there are no more files to open, just closes the current file. STDIN will not be closed.
For example:
$ ruby argf.rb foo bar ARGF.filename #=> "foo" ARGF.close ARGF.filename #=> "bar" ARGF.close
static VALUE argf_close_m(VALUE argf) { next_argv(); argf_close(argf); if (ARGF.next_p != -1) { ARGF.next_p = 1; } ARGF.lineno = 0; return argf; }
Returns true if the current file has been closed; false otherwise. Use ARGF.close
to actually close the current file.
static VALUE argf_closed(VALUE argf) { next_argv(); ARGF_FORWARD(0, 0); return rb_io_closed_p(ARGF.current_file); }
Returns an enumerator which iterates over each line (separated by sep, which defaults to your platform’s newline character) of each file in ARGV
. If a block is supplied, each line in turn will be yielded to the block, otherwise an enumerator is returned. The optional limit argument is an Integer
specifying the maximum length of each line; longer lines will be split according to this limit.
This method allows you to treat the files supplied on the command line as a single file consisting of the concatenation of each named file. After the last line of the first file has been returned, the first line of the second file is returned. The ARGF.filename
and ARGF.lineno
methods can be used to determine the filename of the current line and line number of the whole input, respectively.
For example, the following code prints out each line of each named file prefixed with its line number, displaying the filename once per file:
ARGF.each_line do |line| puts ARGF.filename if ARGF.file.lineno == 1 puts "#{ARGF.file.lineno}: #{line}" end
While the following code prints only the first file’s name at first, and the contents with line number counted through all named files.
ARGF.each_line do |line| puts ARGF.filename if ARGF.lineno == 1 puts "#{ARGF.lineno}: #{line}" end
static VALUE argf_each_line(int argc, VALUE *argv, VALUE argf) { RETURN_ENUMERATOR(argf, argc, argv); FOREACH_ARGF() { argf_block_call_line(rb_intern("each_line"), argc, argv, argf); } return argf; }
Iterates over each byte of each file in ARGV
. A byte is returned as an Integer
in the range 0..255.
This method allows you to treat the files supplied on the command line as a single file consisting of the concatenation of each named file. After the last byte of the first file has been returned, the first byte of the second file is returned. The ARGF.filename
method can be used to determine the filename of the current byte.
If no block is given, an enumerator is returned instead.
For example:
ARGF.bytes.to_a #=> [35, 32, ... 95, 10]
static VALUE argf_each_byte(VALUE argf) { RETURN_ENUMERATOR(argf, 0, 0); FOREACH_ARGF() { argf_block_call(rb_intern("each_byte"), 0, 0, argf); } return argf; }
Iterates over each character of each file in ARGF
.
This method allows you to treat the files supplied on the command line as a single file consisting of the concatenation of each named file. After the last character of the first file has been returned, the first character of the second file is returned. The ARGF.filename
method can be used to determine the name of the file in which the current character appears.
If no block is given, an enumerator is returned instead.
static VALUE argf_each_char(VALUE argf) { RETURN_ENUMERATOR(argf, 0, 0); FOREACH_ARGF() { argf_block_call(rb_intern("each_char"), 0, 0, argf); } return argf; }
Iterates over each codepoint of each file in ARGF
.
This method allows you to treat the files supplied on the command line as a single file consisting of the concatenation of each named file. After the last codepoint of the first file has been returned, the first codepoint of the second file is returned. The ARGF.filename
method can be used to determine the name of the file in which the current codepoint appears.
If no block is given, an enumerator is returned instead.
static VALUE argf_each_codepoint(VALUE argf) { RETURN_ENUMERATOR(argf, 0, 0); FOREACH_ARGF() { argf_block_call(rb_intern("each_codepoint"), 0, 0, argf); } return argf; }
Returns an enumerator which iterates over each line (separated by sep, which defaults to your platform’s newline character) of each file in ARGV
. If a block is supplied, each line in turn will be yielded to the block, otherwise an enumerator is returned. The optional limit argument is an Integer
specifying the maximum length of each line; longer lines will be split according to this limit.
This method allows you to treat the files supplied on the command line as a single file consisting of the concatenation of each named file. After the last line of the first file has been returned, the first line of the second file is returned. The ARGF.filename
and ARGF.lineno
methods can be used to determine the filename of the current line and line number of the whole input, respectively.
For example, the following code prints out each line of each named file prefixed with its line number, displaying the filename once per file:
ARGF.each_line do |line| puts ARGF.filename if ARGF.file.lineno == 1 puts "#{ARGF.file.lineno}: #{line}" end
While the following code prints only the first file’s name at first, and the contents with line number counted through all named files.
ARGF.each_line do |line| puts ARGF.filename if ARGF.lineno == 1 puts "#{ARGF.lineno}: #{line}" end
Returns true if the current file in ARGF
is at end of file, i.e. it has no data to read. The stream must be opened for reading or an IOError
will be raised.
$ echo "eof" | ruby argf.rb ARGF.eof? #=> false 3.times { ARGF.readchar } ARGF.eof? #=> false ARGF.readchar #=> "\n" ARGF.eof? #=> true
static VALUE argf_eof(VALUE argf) { next_argv(); if (RTEST(ARGF.current_file)) { if (ARGF.init_p == 0) return Qtrue; next_argv(); ARGF_FORWARD(0, 0); if (rb_io_eof(ARGF.current_file)) { return Qtrue; } } return Qfalse; }
Returns true if the current file in ARGF
is at end of file, i.e. it has no data to read. The stream must be opened for reading or an IOError
will be raised.
$ echo "eof" | ruby argf.rb ARGF.eof? #=> false 3.times { ARGF.readchar } ARGF.eof? #=> false ARGF.readchar #=> "\n" ARGF.eof? #=> true
Returns the external encoding for files read from ARGF
as an Encoding
object. The external encoding is the encoding of the text as stored in a file. Contrast with ARGF.internal_encoding
, which is the encoding used to represent this text within Ruby.
To set the external encoding use ARGF.set_encoding
.
For example:
ARGF.external_encoding #=> #<Encoding:UTF-8>
static VALUE argf_external_encoding(VALUE argf) { return argf_encoding(argf, rb_io_external_encoding); }
Returns the current file as an IO
or File
object. $stdin
is returned when the current file is STDIN.
For example:
$ echo "foo" > foo $ echo "bar" > bar $ ruby argf.rb foo bar ARGF.file #=> #<File:foo> ARGF.read(5) #=> "foo\nb" ARGF.file #=> #<File:bar>
static VALUE argf_file(VALUE argf) { next_argv(); return ARGF.current_file; }
Returns the current filename. “-” is returned when the current file is STDIN.
For example:
$ echo "foo" > foo $ echo "bar" > bar $ echo "glark" > glark $ ruby argf.rb foo bar glark ARGF.filename #=> "foo" ARGF.read(5) #=> "foo\nb" ARGF.filename #=> "bar" ARGF.skip ARGF.filename #=> "glark"
static VALUE argf_filename(VALUE argf) { next_argv(); return ARGF.filename; }
Returns an integer representing the numeric file descriptor for the current file. Raises an ArgumentError
if there isn’t a current file.
ARGF.fileno #=> 3
static VALUE argf_fileno(VALUE argf) { if (!next_argv()) { rb_raise(rb_eArgError, "no stream"); } ARGF_FORWARD(0, 0); return rb_io_fileno(ARGF.current_file); }
Gets the next 8-bit byte (0..255) from ARGF
. Returns nil
if called at the end of the stream.
For example:
$ echo "foo" > file $ ruby argf.rb file ARGF.getbyte #=> 102 ARGF.getbyte #=> 111 ARGF.getbyte #=> 111 ARGF.getbyte #=> 10 ARGF.getbyte #=> nil
static VALUE argf_getbyte(VALUE argf) { VALUE ch; retry: if (!next_argv()) return Qnil; if (!RB_TYPE_P(ARGF.current_file, T_FILE)) { ch = forward_current(rb_intern("getbyte"), 0, 0); } else { ch = rb_io_getbyte(ARGF.current_file); } if (NIL_P(ch) && ARGF.next_p != -1) { argf_close(argf); ARGF.next_p = 1; goto retry; } return ch; }
Reads the next character from ARGF
and returns it as a String
. Returns nil
at the end of the stream.
ARGF
treats the files named on the command line as a single file created by concatenating their contents. After returning the last character of the first file, it returns the first character of the second file, and so on.
For example:
$ echo "foo" > file $ ruby argf.rb file ARGF.getc #=> "f" ARGF.getc #=> "o" ARGF.getc #=> "o" ARGF.getc #=> "\n" ARGF.getc #=> nil ARGF.getc #=> nil
static VALUE argf_getc(VALUE argf) { VALUE ch; retry: if (!next_argv()) return Qnil; if (ARGF_GENERIC_INPUT_P()) { ch = forward_current(rb_intern("getc"), 0, 0); } else { ch = rb_io_getc(ARGF.current_file); } if (NIL_P(ch) && ARGF.next_p != -1) { argf_close(argf); ARGF.next_p = 1; goto retry; } return ch; }
Returns the next line from the current file in ARGF
.
By default lines are assumed to be separated by $/
; to use a different character as a separator, supply it as a String
for the sep argument.
The optional limit argument specifies how many characters of each line to return. By default all characters are returned.
See IO.readlines
for details about getline_args.
static VALUE argf_gets(int argc, VALUE *argv, VALUE argf) { VALUE line; line = argf_getline(argc, argv, argf); rb_lastline_set(line); return line; }
Returns the file extension appended to the names of backup copies of modified files under in-place edit mode. This value can be set using ARGF.inplace_mode=
or passing the -i
switch to the Ruby binary.
static VALUE argf_inplace_mode_get(VALUE argf) { if (!ARGF.inplace) return Qnil; if (NIL_P(ARGF.inplace)) return rb_str_new(0, 0); return rb_str_dup(ARGF.inplace); }
Sets the filename extension for in-place editing mode to the given String
. The backup copy of each file being edited has this value appended to its filename.
For example:
$ ruby argf.rb file.txt ARGF.inplace_mode = '.bak' ARGF.each_line do |line| print line.sub("foo","bar") end
First, file.txt.bak is created as a backup copy of file.txt. Then, each line of file.txt has the first occurrence of “foo” replaced with “bar”.
static VALUE argf_inplace_mode_set(VALUE argf, VALUE val) { if (!RTEST(val)) { ARGF.inplace = Qfalse; } else if (StringValueCStr(val), !RSTRING_LEN(val)) { ARGF.inplace = Qnil; } else { ARGF.inplace = rb_str_new_frozen(val); } return argf; }
Returns the internal encoding for strings read from ARGF
as an Encoding
object.
If ARGF.set_encoding
has been called with two encoding names, the second is returned. Otherwise, if Encoding.default_external
has been set, that value is returned. Failing that, if a default external encoding was specified on the command-line, that value is used. If the encoding is unknown, nil
is returned.
static VALUE argf_internal_encoding(VALUE argf) { return argf_encoding(argf, rb_io_internal_encoding); }
Returns the current line number of ARGF
as a whole. This value can be set manually with ARGF.lineno=
.
For example:
ARGF.lineno #=> 0 ARGF.readline #=> "This is line 1\n" ARGF.lineno #=> 1
static VALUE argf_lineno(VALUE argf) { return INT2FIX(ARGF.lineno); }
Sets the line number of ARGF
as a whole to the given Integer
.
ARGF
sets the line number automatically as you read data, so normally you will not need to set it explicitly. To access the current line number use ARGF.lineno
.
For example:
ARGF.lineno #=> 0 ARGF.readline #=> "This is line 1\n" ARGF.lineno #=> 1 ARGF.lineno = 0 #=> 0 ARGF.lineno #=> 0
static VALUE argf_set_lineno(VALUE argf, VALUE val) { ARGF.lineno = NUM2INT(val); ARGF.last_lineno = ARGF.lineno; return val; }
Returns the current filename. “-” is returned when the current file is STDIN.
For example:
$ echo "foo" > foo $ echo "bar" > bar $ echo "glark" > glark $ ruby argf.rb foo bar glark ARGF.filename #=> "foo" ARGF.read(5) #=> "foo\nb" ARGF.filename #=> "bar" ARGF.skip ARGF.filename #=> "glark"
Returns the current offset (in bytes) of the current file in ARGF
.
ARGF.pos #=> 0 ARGF.gets #=> "This is line one\n" ARGF.pos #=> 17
Seeks to the position given by position (in bytes) in ARGF
.
For example:
ARGF.pos = 17 ARGF.gets #=> "This is line two\n"
static VALUE argf_set_pos(VALUE argf, VALUE offset) { if (!next_argv()) { rb_raise(rb_eArgError, "no stream to set position"); } ARGF_FORWARD(1, &offset); return rb_io_set_pos(ARGF.current_file, offset); }
Writes the given objects to the stream; returns nil
. Appends the output record separator $OUTPUT_RECORD_SEPARATOR
($\
), if it is not nil
. See Line IO.
With argument objects
given, for each object:
-
Converts via its method
to_s
if not a string. -
Writes to the stream.
-
If not the last object, writes the output field separator
$OUTPUT_FIELD_SEPARATOR
($,
) if it is notnil
.
With default separators:
f = File.open('t.tmp', 'w+') objects = [0, 0.0, Rational(0, 1), Complex(0, 0), :zero, 'zero'] p $OUTPUT_RECORD_SEPARATOR p $OUTPUT_FIELD_SEPARATOR f.print(*objects) f.rewind p f.read f.close
Output:
nil nil "00.00/10+0izerozero"
With specified separators:
$\ = "\n" $, = ',' f.rewind f.print(*objects) f.rewind p f.read
Output:
"0,0.0,0/1,0+0i,zero,zero\n"
With no argument given, writes the content of $_
(which is usually the most recent user input):
f = File.open('t.tmp', 'w+') gets # Sets $_ to the most recent user input. f.print f.close
VALUE rb_io_print(int argc, const VALUE *argv, VALUE out) { int i; VALUE line; /* if no argument given, print `$_' */ if (argc == 0) { argc = 1; line = rb_lastline_get(); argv = &line; } if (argc > 1 && !NIL_P(rb_output_fs)) { rb_category_warn(RB_WARN_CATEGORY_DEPRECATED, "$, is set to non-nil value"); } for (i=0; i<argc; i++) { if (!NIL_P(rb_output_fs) && i>0) { rb_io_write(out, rb_output_fs); } rb_io_write(out, argv[i]); } if (argc > 0 && !NIL_P(rb_output_rs)) { rb_io_write(out, rb_output_rs); } return Qnil; }
Formats and writes objects
to the stream.
For details on format_string
, see Format Specifications.
VALUE rb_io_printf(int argc, const VALUE *argv, VALUE out) { rb_io_write(out, rb_f_sprintf(argc, argv)); return Qnil; }
Writes a character to the stream. See Character IO.
If object
is numeric, converts to integer if necessary, then writes the character whose code is the least significant byte; if object
is a string, writes the first character:
$stdout.putc "A" $stdout.putc 65
Output:
AA
static VALUE rb_io_putc(VALUE io, VALUE ch) { VALUE str; if (RB_TYPE_P(ch, T_STRING)) { str = rb_str_substr(ch, 0, 1); } else { char c = NUM2CHR(ch); str = rb_str_new(&c, 1); } rb_io_write(io, str); return ch; }
Writes the given objects
to the stream, which must be open for writing; returns nil
.\ Writes a newline after each that does not already end with a newline sequence. If called without arguments, writes a newline. See Line IO.
Note that each added newline is the character "\n"<//tt>, not the output record separator (<tt>$\
).
Treatment for each object:
-
String: writes the string.
-
Neither string nor array: writes
object.to_s
. -
Array: writes each element of the array; arrays may be nested.
To keep these examples brief, we define this helper method:
def show(*objects) # Puts objects to file. f = File.new('t.tmp', 'w+') f.puts(objects) # Return file content. f.rewind p f.read f.close end # Strings without newlines. show('foo', 'bar', 'baz') # => "foo\nbar\nbaz\n" # Strings, some with newlines. show("foo\n", 'bar', "baz\n") # => "foo\nbar\nbaz\n" # Neither strings nor arrays: show(0, 0.0, Rational(0, 1), Complex(9, 0), :zero) # => "0\n0.0\n0/1\n9+0i\nzero\n" # Array of strings. show(['foo', "bar\n", 'baz']) # => "foo\nbar\nbaz\n" # Nested arrays. show([[[0, 1], 2, 3], 4, 5]) # => "0\n1\n2\n3\n4\n5\n"
VALUE rb_io_puts(int argc, const VALUE *argv, VALUE out) { VALUE line, args[2]; /* if no argument given, print newline. */ if (argc == 0) { rb_io_write(out, rb_default_rs); return Qnil; } for (int i = 0; i < argc; i++) { // Convert the argument to a string: if (RB_TYPE_P(argv[i], T_STRING)) { line = argv[i]; } else if (rb_exec_recursive(io_puts_ary, argv[i], out)) { continue; } else { line = rb_obj_as_string(argv[i]); } // Write the line: int n = 0; if (RSTRING_LEN(line) == 0) { args[n++] = rb_default_rs; } else { args[n++] = line; if (!rb_str_end_with_asciichar(line, '\n')) { args[n++] = rb_default_rs; } } rb_io_writev(out, n, args); } return Qnil; }
Reads length bytes from ARGF
. The files named on the command line are concatenated and treated as a single file by this method, so when called without arguments the contents of this pseudo file are returned in their entirety.
length must be a non-negative integer or nil
.
If length is a positive integer, read
tries to read length bytes without any conversion (binary mode). It returns nil
if an EOF is encountered before anything can be read. Fewer than length bytes are returned if an EOF is encountered during the read. In the case of an integer length, the resulting string is always in ASCII-8BIT encoding.
If length is omitted or is nil
, it reads until EOF and the encoding conversion is applied, if applicable. A string is returned even if EOF is encountered before any data is read.
If length is zero, it returns an empty string (""
).
If the optional outbuf argument is present, it must reference a String
, which will receive the data. The outbuf will contain only the received data after the method call even if it is not empty at the beginning.
For example:
$ echo "small" > small.txt $ echo "large" > large.txt $ ./glark.rb small.txt large.txt ARGF.read #=> "small\nlarge" ARGF.read(200) #=> "small\nlarge" ARGF.read(2) #=> "sm" ARGF.read(0) #=> ""
Note that this method behaves like the fread() function in C. This means it retries to invoke read(2) system calls to read data with the specified length. If you need the behavior like a single read(2) system call, consider ARGF#readpartial
or ARGF#read_nonblock
.
static VALUE argf_read(int argc, VALUE *argv, VALUE argf) { VALUE tmp, str, length; long len = 0; rb_scan_args(argc, argv, "02", &length, &str); if (!NIL_P(length)) { len = NUM2LONG(argv[0]); } if (!NIL_P(str)) { StringValue(str); rb_str_resize(str,0); argv[1] = Qnil; } retry: if (!next_argv()) { return str; } if (ARGF_GENERIC_INPUT_P()) { tmp = argf_forward(argc, argv, argf); } else { tmp = io_read(argc, argv, ARGF.current_file); } if (NIL_P(str)) str = tmp; else if (!NIL_P(tmp)) rb_str_append(str, tmp); if (NIL_P(tmp) || NIL_P(length)) { if (ARGF.next_p != -1) { argf_close(argf); ARGF.next_p = 1; goto retry; } } else if (argc >= 1) { long slen = RSTRING_LEN(str); if (slen < len) { argv[0] = LONG2NUM(len - slen); goto retry; } } return str; }
Reads at most maxlen bytes from the ARGF
stream in non-blocking mode.
static VALUE argf_read_nonblock(int argc, VALUE *argv, VALUE argf) { VALUE opts; rb_scan_args(argc, argv, "11:", NULL, NULL, &opts); if (!NIL_P(opts)) argc--; return argf_getpartial(argc, argv, argf, opts, 1); }
Reads the next 8-bit byte from ARGF
and returns it as an Integer
. Raises an EOFError
after the last byte of the last file has been read.
For example:
$ echo "foo" > file $ ruby argf.rb file ARGF.readbyte #=> 102 ARGF.readbyte #=> 111 ARGF.readbyte #=> 111 ARGF.readbyte #=> 10 ARGF.readbyte #=> end of file reached (EOFError)
static VALUE argf_readbyte(VALUE argf) { VALUE c; NEXT_ARGF_FORWARD(0, 0); c = argf_getbyte(argf); if (NIL_P(c)) { rb_eof_error(); } return c; }
Reads the next character from ARGF
and returns it as a String
. Raises an EOFError
after the last character of the last file has been read.
For example:
$ echo "foo" > file $ ruby argf.rb file ARGF.readchar #=> "f" ARGF.readchar #=> "o" ARGF.readchar #=> "o" ARGF.readchar #=> "\n" ARGF.readchar #=> end of file reached (EOFError)
static VALUE argf_readchar(VALUE argf) { VALUE ch; retry: if (!next_argv()) rb_eof_error(); if (!RB_TYPE_P(ARGF.current_file, T_FILE)) { ch = forward_current(rb_intern("getc"), 0, 0); } else { ch = rb_io_getc(ARGF.current_file); } if (NIL_P(ch) && ARGF.next_p != -1) { argf_close(argf); ARGF.next_p = 1; goto retry; } return ch; }
Returns the next line from the current file in ARGF
.
By default lines are assumed to be separated by $/
; to use a different character as a separator, supply it as a String
for the sep argument.
The optional limit argument specifies how many characters of each line to return. By default all characters are returned.
An EOFError
is raised at the end of the file.
static VALUE argf_readline(int argc, VALUE *argv, VALUE argf) { VALUE line; if (!next_argv()) rb_eof_error(); ARGF_FORWARD(argc, argv); line = argf_gets(argc, argv, argf); if (NIL_P(line)) { rb_eof_error(); } return line; }
Reads each file in ARGF
in its entirety, returning an Array
containing lines from the files. Lines are assumed to be separated by sep.
lines = ARGF.readlines lines[0] #=> "This is line one\n"
See IO.readlines
for a full description of all options.
static VALUE argf_readlines(int argc, VALUE *argv, VALUE argf) { long lineno = ARGF.lineno; VALUE lines, ary; ary = rb_ary_new(); while (next_argv()) { if (ARGF_GENERIC_INPUT_P()) { lines = forward_current(rb_intern("readlines"), argc, argv); } else { lines = rb_io_readlines(argc, argv, ARGF.current_file); argf_close(argf); } ARGF.next_p = 1; rb_ary_concat(ary, lines); ARGF.lineno = lineno + RARRAY_LEN(ary); ARGF.last_lineno = ARGF.lineno; } ARGF.init_p = 0; return ary; }
Reads at most maxlen bytes from the ARGF
stream.
If the optional outbuf argument is present, it must reference a String
, which will receive the data. The outbuf will contain only the received data after the method call even if it is not empty at the beginning.
It raises EOFError
on end of ARGF
stream. Since ARGF
stream is a concatenation of multiple files, internally EOF is occur for each file. ARGF.readpartial
returns empty strings for EOFs except the last one and raises EOFError
for the last one.
static VALUE argf_readpartial(int argc, VALUE *argv, VALUE argf) { return argf_getpartial(argc, argv, argf, Qnil, 0); }
Positions the current file to the beginning of input, resetting ARGF.lineno
to zero.
ARGF.readline #=> "This is line one\n" ARGF.rewind #=> 0 ARGF.lineno #=> 0 ARGF.readline #=> "This is line one\n"
static VALUE argf_rewind(VALUE argf) { VALUE ret; int old_lineno; if (!next_argv()) { rb_raise(rb_eArgError, "no stream to rewind"); } ARGF_FORWARD(0, 0); old_lineno = RFILE(ARGF.current_file)->fptr->lineno; ret = rb_io_rewind(ARGF.current_file); if (!global_argf_p(argf)) { ARGF.last_lineno = ARGF.lineno -= old_lineno; } return ret; }
Seeks to offset amount (an Integer
) in the ARGF
stream according to the value of whence. See IO#seek
for further details.
static VALUE argf_seek_m(int argc, VALUE *argv, VALUE argf) { if (!next_argv()) { rb_raise(rb_eArgError, "no stream to seek"); } ARGF_FORWARD(argc, argv); return rb_io_seek_m(argc, argv, ARGF.current_file); }
If single argument is specified, strings read from ARGF
are tagged with the encoding specified.
If two encoding names separated by a colon are given, e.g. “ascii:utf-8”, the read string is converted from the first encoding (external encoding) to the second encoding (internal encoding), then tagged with the second encoding.
If two arguments are specified, they must be encoding objects or encoding names. Again, the first specifies the external encoding; the second specifies the internal encoding.
If the external encoding and the internal encoding are specified, the optional Hash
argument can be used to adjust the conversion process. The structure of this hash is explained in the String#encode
documentation.
For example:
ARGF.set_encoding('ascii') # Tag the input as US-ASCII text ARGF.set_encoding(Encoding::UTF_8) # Tag the input as UTF-8 text ARGF.set_encoding('utf-8','ascii') # Transcode the input from US-ASCII # to UTF-8.
static VALUE argf_set_encoding(int argc, VALUE *argv, VALUE argf) { rb_io_t *fptr; if (!next_argv()) { rb_raise(rb_eArgError, "no stream to set encoding"); } rb_io_set_encoding(argc, argv, ARGF.current_file); GetOpenFile(ARGF.current_file, fptr); ARGF.encs = fptr->encs; return argf; }
Sets the current file to the next file in ARGV. If there aren’t any more files it has no effect.
For example:
$ ruby argf.rb foo bar ARGF.filename #=> "foo" ARGF.skip ARGF.filename #=> "bar"
static VALUE argf_skip(VALUE argf) { if (ARGF.init_p && ARGF.next_p == 0) { argf_close(argf); ARGF.next_p = 1; } return argf; }
Returns the current offset (in bytes) of the current file in ARGF
.
ARGF.pos #=> 0 ARGF.gets #=> "This is line one\n" ARGF.pos #=> 17
static VALUE argf_tell(VALUE argf) { if (!next_argv()) { rb_raise(rb_eArgError, "no stream to tell"); } ARGF_FORWARD(0, 0); return rb_io_tell(ARGF.current_file); }
Reads each file in ARGF
in its entirety, returning an Array
containing lines from the files. Lines are assumed to be separated by sep.
lines = ARGF.readlines lines[0] #=> "This is line one\n"
See IO.readlines
for a full description of all options.
Returns an integer representing the numeric file descriptor for the current file. Raises an ArgumentError
if there isn’t a current file.
ARGF.fileno #=> 3
Returns an IO
object representing the current file. This will be a File
object unless the current file is a stream such as STDIN.
For example:
ARGF.to_io #=> #<File:glark.txt> ARGF.to_io #=> #<IO:<STDIN>>
static VALUE argf_to_io(VALUE argf) { next_argv(); ARGF_FORWARD(0, 0); return ARGF.current_file; }
Returns “ARGF”.
static VALUE argf_to_s(VALUE argf) { return rb_str_new2("ARGF"); }
Returns IO
instance tied to ARGF for writing if inplace mode is enabled.
static VALUE argf_write_io(VALUE argf) { if (!RTEST(ARGF.current_file)) { rb_raise(rb_eIOError, "not opened for writing"); } return GetWriteIO(ARGF.current_file); }
Writes string if inplace mode.
static VALUE argf_write(VALUE argf, VALUE str) { return rb_io_write(argf_write_io(argf), str); }