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+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+/*
+	Package fmt implements formatted I/O with functions analogous
+	to C's printf and scanf.  The format 'verbs' are derived from C's but
+	are simpler.
+
+
+	Printing
+
+	The verbs:
+
+	General:
+		%v	the value in a default format
+			when printing structs, the plus flag (%+v) adds field names
+		%#v	a Go-syntax representation of the value
+		%T	a Go-syntax representation of the type of the value
+		%%	a literal percent sign; consumes no value
+
+	Boolean:
+		%t	the word true or false
+	Integer:
+		%b	base 2
+		%c	the character represented by the corresponding Unicode code point
+		%d	base 10
+		%o	base 8
+		%q	a single-quoted character literal safely escaped with Go syntax.
+		%x	base 16, with lower-case letters for a-f
+		%X	base 16, with upper-case letters for A-F
+		%U	Unicode format: U+1234; same as "U+%04X"
+	Floating-point and complex constituents:
+		%b	decimalless scientific notation with exponent a power of two,
+			in the manner of strconv.FormatFloat with the 'b' format,
+			e.g. -123456p-78
+		%e	scientific notation, e.g. -1234.456e+78
+		%E	scientific notation, e.g. -1234.456E+78
+		%f	decimal point but no exponent, e.g. 123.456
+		%F	synonym for %f
+		%g	%e for large exponents, %f otherwise
+		%G	%E for large exponents, %F otherwise
+	String and slice of bytes:
+		%s	the uninterpreted bytes of the string or slice
+		%q	a double-quoted string safely escaped with Go syntax
+		%x	base 16, lower-case, two characters per byte
+		%X	base 16, upper-case, two characters per byte
+	Pointer:
+		%p	base 16 notation, with leading 0x
+
+	There is no 'u' flag.  Integers are printed unsigned if they have unsigned type.
+	Similarly, there is no need to specify the size of the operand (int8, int64).
+
+	The default format for %v is:
+		bool:                    %t
+		int, int8 etc.:          %d
+		uint, uint8 etc.:        %d, %x if printed with %#v
+		float32, complex64, etc: %g
+		string:                  %s
+		chan:                    %p
+		pointer:                 %p
+	For compound objects, the elements are printed using these rules, recursively,
+	laid out like this:
+		struct:             {field0 field1 ...}
+		array, slice:       [elem0  elem1 ...]
+		maps:               map[key1:value1 key2:value2]
+		pointer to above:   &{}, &[], &map[]
+
+	Width is specified by an optional decimal number immediately following the verb.
+	If absent, the width is whatever is necessary to represent the value.
+	Precision is specified after the (optional) width by a period followed by a
+	decimal number. If no period is present, a default precision is used.
+	A period with no following number specifies a precision of zero.
+	Examples:
+		%f:    default width, default precision
+		%9f    width 9, default precision
+		%.2f   default width, precision 2
+		%9.2f  width 9, precision 2
+		%9.f   width 9, precision 0
+
+	Width and precision are measured in units of Unicode code points,
+	that is, runes. (This differs from C's printf where the
+	units are always measured in bytes.) Either or both of the flags
+	may be replaced with the character '*', causing their values to be
+	obtained from the next operand, which must be of type int.
+
+	For most values, width is the minimum number of runes to output,
+	padding the formatted form with spaces if necessary.
+
+	For strings, byte slices and byte arrays, however, precision
+	limits the length of the input to be formatted (not the size of
+	the output), truncating if necessary. Normally it is measured in
+	runes, but for these types when formatted with the %x or %X format
+	it is measured in bytes.
+
+	For floating-point values, width sets the minimum width of the field and
+	precision sets the number of places after the decimal, if appropriate,
+	except that for %g/%G it sets the total number of digits. For example,
+	given 123.45 the format %6.2f prints 123.45 while %.4g prints 123.5.
+	The default precision for %e and %f is 6; for %g it is the smallest
+	number of digits necessary to identify the value uniquely.
+
+	For complex numbers, the width and precision apply to the two
+	components independently and the result is parenthesized, so %f applied
+	to 1.2+3.4i produces (1.200000+3.400000i).
+
+	Other flags:
+		+	always print a sign for numeric values;
+			guarantee ASCII-only output for %q (%+q)
+		-	pad with spaces on the right rather than the left (left-justify the field)
+		#	alternate format: add leading 0 for octal (%#o), 0x for hex (%#x);
+			0X for hex (%#X); suppress 0x for %p (%#p);
+			for %q, print a raw (backquoted) string if strconv.CanBackquote
+			returns true;
+			write e.g. U+0078 'x' if the character is printable for %U (%#U).
+		' '	(space) leave a space for elided sign in numbers (% d);
+			put spaces between bytes printing strings or slices in hex (% x, % X)
+		0	pad with leading zeros rather than spaces;
+			for numbers, this moves the padding after the sign
+
+	Flags are ignored by verbs that do not expect them.
+	For example there is no alternate decimal format, so %#d and %d
+	behave identically.
+
+	For each Printf-like function, there is also a Print function
+	that takes no format and is equivalent to saying %v for every
+	operand.  Another variant Println inserts blanks between
+	operands and appends a newline.
+
+	Regardless of the verb, if an operand is an interface value,
+	the internal concrete value is used, not the interface itself.
+	Thus:
+		var i interface{} = 23
+		fmt.Printf("%v\n", i)
+	will print 23.
+
+	Except when printed using the verbs %T and %p, special
+	formatting considerations apply for operands that implement
+	certain interfaces. In order of application:
+
+	1. If an operand implements the Formatter interface, it will
+	be invoked. Formatter provides fine control of formatting.
+
+	2. If the %v verb is used with the # flag (%#v) and the operand
+	implements the GoStringer interface, that will be invoked.
+
+	If the format (which is implicitly %v for Println etc.) is valid
+	for a string (%s %q %v %x %X), the following two rules apply:
+
+	3. If an operand implements the error interface, the Error method
+	will be invoked to convert the object to a string, which will then
+	be formatted as required by the verb (if any).
+
+	4. If an operand implements method String() string, that method
+	will be invoked to convert the object to a string, which will then
+	be formatted as required by the verb (if any).
+
+	For compound operands such as slices and structs, the format
+	applies to the elements of each operand, recursively, not to the
+	operand as a whole. Thus %q will quote each element of a slice
+	of strings, and %6.2f will control formatting for each element
+	of a floating-point array.
+
+	To avoid recursion in cases such as
+		type X string
+		func (x X) String() string { return Sprintf("<%s>", x) }
+	convert the value before recurring:
+		func (x X) String() string { return Sprintf("<%s>", string(x)) }
+	Infinite recursion can also be triggered by self-referential data
+	structures, such as a slice that contains itself as an element, if
+	that type has a String method. Such pathologies are rare, however,
+	and the package does not protect against them.
+
+	Explicit argument indexes:
+
+	In Printf, Sprintf, and Fprintf, the default behavior is for each
+	formatting verb to format successive arguments passed in the call.
+	However, the notation [n] immediately before the verb indicates that the
+	nth one-indexed argument is to be formatted instead. The same notation
+	before a '*' for a width or precision selects the argument index holding
+	the value. After processing a bracketed expression [n], arguments n+1,
+	n+2, etc. will be processed unless otherwise directed.
+
+	For example,
+		fmt.Sprintf("%[2]d %[1]d\n", 11, 22)
+	will yield "22 11", while
+		fmt.Sprintf("%[3]*.[2]*[1]f", 12.0, 2, 6),
+	equivalent to
+		fmt.Sprintf("%6.2f", 12.0),
+	will yield " 12.00". Because an explicit index affects subsequent verbs,
+	this notation can be used to print the same values multiple times
+	by resetting the index for the first argument to be repeated:
+		fmt.Sprintf("%d %d %#[1]x %#x", 16, 17)
+	will yield "16 17 0x10 0x11".
+
+	Format errors:
+
+	If an invalid argument is given for a verb, such as providing
+	a string to %d, the generated string will contain a
+	description of the problem, as in these examples:
+
+		Wrong type or unknown verb: %!verb(type=value)
+			Printf("%d", hi):          %!d(string=hi)
+		Too many arguments: %!(EXTRA type=value)
+			Printf("hi", "guys"):      hi%!(EXTRA string=guys)
+		Too few arguments: %!verb(MISSING)
+			Printf("hi%d"):            hi %!d(MISSING)
+		Non-int for width or precision: %!(BADWIDTH) or %!(BADPREC)
+			Printf("%*s", 4.5, "hi"):  %!(BADWIDTH)hi
+			Printf("%.*s", 4.5, "hi"): %!(BADPREC)hi
+		Invalid or invalid use of argument index: %!(BADINDEX)
+			Printf("%*[2]d", 7):       %!d(BADINDEX)
+			Printf("%.[2]d", 7):       %!d(BADINDEX)
+
+	All errors begin with the string "%!" followed sometimes
+	by a single character (the verb) and end with a parenthesized
+	description.
+
+	If an Error or String method triggers a panic when called by a
+	print routine, the fmt package reformats the error message
+	from the panic, decorating it with an indication that it came
+	through the fmt package.  For example, if a String method
+	calls panic("bad"), the resulting formatted message will look
+	like
+		%!s(PANIC=bad)
+
+	The %!s just shows the print verb in use when the failure
+	occurred.
+
+	Scanning
+
+	An analogous set of functions scans formatted text to yield
+	values.  Scan, Scanf and Scanln read from os.Stdin; Fscan,
+	Fscanf and Fscanln read from a specified io.Reader; Sscan,
+	Sscanf and Sscanln read from an argument string.  Scanln,
+	Fscanln and Sscanln stop scanning at a newline and require that
+	the items be followed by one; Scanf, Fscanf and Sscanf require
+	newlines in the input to match newlines in the format; the other
+	routines treat newlines as spaces.
+
+	Scanf, Fscanf, and Sscanf parse the arguments according to a
+	format string, analogous to that of Printf.  For example, %x
+	will scan an integer as a hexadecimal number, and %v will scan
+	the default representation format for the value.
+
+	The formats behave analogously to those of Printf with the
+	following exceptions:
+
+		%p is not implemented
+		%T is not implemented
+		%e %E %f %F %g %G are all equivalent and scan any floating point or complex value
+		%s and %v on strings scan a space-delimited token
+		Flags # and + are not implemented.
+
+	The familiar base-setting prefixes 0 (octal) and 0x
+	(hexadecimal) are accepted when scanning integers without a
+	format or with the %v verb.
+
+	Width is interpreted in the input text (%5s means at most
+	five runes of input will be read to scan a string) but there
+	is no syntax for scanning with a precision (no %5.2f, just
+	%5f).
+
+	When scanning with a format, all non-empty runs of space
+	characters (except newline) are equivalent to a single
+	space in both the format and the input.  With that proviso,
+	text in the format string must match the input text; scanning
+	stops if it does not, with the return value of the function
+	indicating the number of arguments scanned.
+
+	In all the scanning functions, a carriage return followed
+	immediately by a newline is treated as a plain newline
+	(\r\n means the same as \n).
+
+	In all the scanning functions, if an operand implements method
+	Scan (that is, it implements the Scanner interface) that
+	method will be used to scan the text for that operand.  Also,
+	if the number of arguments scanned is less than the number of
+	arguments provided, an error is returned.
+
+	All arguments to be scanned must be either pointers to basic
+	types or implementations of the Scanner interface.
+
+	Note: Fscan etc. can read one character (rune) past the input
+	they return, which means that a loop calling a scan routine
+	may skip some of the input.  This is usually a problem only
+	when there is no space between input values.  If the reader
+	provided to Fscan implements ReadRune, that method will be used
+	to read characters.  If the reader also implements UnreadRune,
+	that method will be used to save the character and successive
+	calls will not lose data.  To attach ReadRune and UnreadRune
+	methods to a reader without that capability, use
+	bufio.NewReader.
+*/
+package fmt