Add RDoc documentation for stuff in object.c

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@5330 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

sprintf.c

@@ -129,6 +129,105 @@ sign_bits(base, p)
     val = NUM2INT(tmp); \
 } while (0)
 
+
+/*
+ *  call-seq:
+ *     format(format_string [, arguments...] )   => string
+ *     sprintf(format_string [, arguments...] )  => string
+ *  
+ *  Returns the string resulting from applying <i>format_string</i> to
+ *  any additional arguments. Within the format string, any characters
+ *  other than format sequences are copied to the result. A format
+ *  sequence consists of a percent sign, followed by optional flags,
+ *  width, and precision indicators, then terminated with a field type
+ *  character. The field type controls how the corresponding
+ *  <code>sprintf</code> argument is to be interpreted, while the flags
+ *  modify that interpretation. The field type characters are listed
+ *  in the table at the end of this section. The flag characters are:
+ *
+ *    Flag     | Applies to   | Meaning
+ *    ---------+--------------+-----------------------------------------
+ *    space    | bdeEfgGioxXu | Leave a space at the start of 
+ *             |              | positive numbers.
+ *    ---------+--------------+-----------------------------------------
+ *    (digit)$ | all          | Specifies the absolute argument number
+ *             |              | for this field. Absolute and relative
+ *             |              | argument numbers cannot be mixed in a
+ *             |              | sprintf string.
+ *    ---------+--------------+-----------------------------------------
+ *     #       | beEfgGoxX    | Use an alternative format. For the
+ *             |              | conversions `o', `x', `X', and `b', 
+ *             |              | prefix the result with ``0'', ``0x'', ``0X'',
+ *             |              |  and ``0b'', respectively. For `e',
+ *             |              | `E', `f', `g', and 'G', force a decimal
+ *             |              | point to be added, even if no digits follow.
+ *             |              | For `g' and 'G', do not remove trailing zeros.
+ *    ---------+--------------+-----------------------------------------
+ *    +        | bdeEfgGioxXu | Add a leading plus sign to positive numbers.
+ *    ---------+--------------+-----------------------------------------
+ *    -        | all          | Left-justify the result of this conversion.
+ *    ---------+--------------+-----------------------------------------
+ *    0 (zero) | all          | Pad with zeros, not spaces.
+ *    ---------+--------------+-----------------------------------------
+ *    *        | all          | Use the next argument as the field width. 
+ *             |              | If negative, left-justify the result. If the
+ *             |              | asterisk is followed by a number and a dollar 
+ *             |              | sign, use the indicated argument as the width.
+ *
+ *     
+ *  The field width is an optional integer, followed optionally by a
+ *  period and a precision. The width specifies the minimum number of
+ *  characters that will be written to the result for this field. For
+ *  numeric fields, the precision controls the number of decimal places
+ *  displayed. For string fields, the precision determines the maximum
+ *  number of characters to be copied from the string. (Thus, the format
+ *  sequence <code>%10.10s</code> will always contribute exactly ten
+ *  characters to the result.)
+ *
+ *  The field types are:
+ *
+ *      Field |  Conversion
+ *      ------+--------------------------------------------------------------
+ *        b   | Convert argument as a binary number.
+ *        c   | Argument is the numeric code for a single character.
+ *        d   | Convert argument as a decimal number.
+ *        E   | Equivalent to `e', but uses an uppercase E to indicate
+ *            | the exponent.
+ *        e   | Convert floating point argument into exponential notation 
+ *            | with one digit before the decimal point. The precision
+ *            | determines the number of fractional digits (defaulting to six).
+ *        f   | Convert floating point argument as [-]ddd.ddd, 
+ *            |  where the precision determines the number of digits after
+ *            | the decimal point.
+ *        G   | Equivalent to `g', but use an uppercase `E' in exponent form.
+ *        g   | Convert a floating point number using exponential form
+ *            | if the exponent is less than -4 or greater than or
+ *            | equal to the precision, or in d.dddd form otherwise.
+ *        i   | Identical to `d'.
+ *        o   | Convert argument as an octal number.
+ *        p   | The valuing of argument.inspect.
+ *        s   | Argument is a string to be substituted. If the format
+ *            | sequence contains a precision, at most that many characters
+ *            | will be copied.
+ *        u   | Treat argument as an unsigned decimal number.
+ *        X   | Convert argument as a hexadecimal number using uppercase
+ *            | letters. Negative numbers will be displayed with two
+ *            | leading periods (representing an infinite string of
+ *            | leading 'FF's.
+ *        x   | Convert argument as a hexadecimal number.
+ *            | Negative numbers will be displayed with two
+ *            | leading periods (representing an infinite string of
+ *            | leading 'ff's.
+ *     
+ *  Examples:
+ *
+ *     sprintf("%d %04x", 123, 123)               #=> "123 007b"
+ *     sprintf("%08b '%4s'", 123, 123)            #=> "01111011 ' 123'"
+ *     sprintf("%1$*2$s %2$d %1$s", "hello", 8)   #=> "   hello 8 hello"
+ *     sprintf("%1$*2$s %2$d", "hello", -8)       #=> "hello    -8"
+ *     sprintf("%+g:% g:%-g", 1.23, 1.23, 1.23)   #=> "+1.23: 1.23:1.23"
+ */
+
 VALUE
 rb_f_sprintf(argc, argv)
     int argc;