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Module: Kernel

Relationships & Source Files
Defined in: ext/bigdecimal/bigdecimal.c

Class Method Summary

Class Method Details

BigDecimal(value, exception: true) ⇒ bigdecimal BigDecimal(value, ndigits, exception: true) ⇒ bigdecimal

Returns the BigDecimal converted from value

with a precision of ndigits decimal digits.

When ndigits is less than the number of significant digits
in the value, the result is rounded to that number of digits,
according to the current rounding mode; see BigDecimal.mode.

Returns value converted to a BigDecimal, depending on the type of value:

  • ::Integer, ::Float, ::Rational, ::Complex, or BigDecimal: converted directly:

    # Integer, Complex, or BigDecimal value does not require ndigits; ignored if given.
BigDecimal(2)                     # => 0.2e1
BigDecimal(Complex(2, 0))         # => 0.2e1
BigDecimal(BigDecimal(2))         # => 0.2e1
# Float or Rational value requires ndigits.
BigDecimal(2.0, 0)                # => 0.2e1
BigDecimal(Rational(2, 1), 0)     # => 0.2e1

  • String: converted by parsing if it contains an integer or floating-point literal; leading and trailing whitespace is ignored:

    # String does not require ndigits; ignored if given.
BigDecimal('2')     # => 0.2e1
BigDecimal('2.0')   # => 0.2e1
BigDecimal('0.2e1') # => 0.2e1
BigDecimal(' 2.0 ') # => 0.2e1

  • Other type that responds to method :to_str: first converted to a string, then converted to a BigDecimal, as above.

  • Other type:

    • Raises an exception if keyword argument exception is true.

    • Returns nil if keyword argument exception is true.

Raises an exception if value evaluates to a ::Float and digits is larger than Float::DIG + 1.

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# File 'ext/bigdecimal/bigdecimal.c', line 3536



static VALUE
f_BigDecimal(int argc, VALUE *argv, VALUE self)
{
    VALUE val, digs_v, opts = Qnil;
    argc = rb_scan_args(argc, argv, "11:", &val, &digs_v, &opts);
    int exception = opts_exception_p(opts);

    size_t digs = SIZE_MAX; /* this means digs is omitted */
    if (argc > 1) {
        digs_v = rb_to_int(digs_v);
        if (FIXNUM_P(digs_v)) {
            long n = FIX2LONG(digs_v);
            if (n < 0)
                goto negative_digs;
            digs = (size_t)n;
        }
        else {
            if (RBIGNUM_NEGATIVE_P(digs_v)) {
              negative_digs:
                if (!exception)
                    return Qnil;
                rb_raise(rb_eArgError, "negative precision");
            }
            digs = NUM2SIZET(digs_v);
        }
    }

    return rb_convert_to_BigDecimal(val, digs, exception);
}