* ext/bigdecimal/bigdecimal.c: Formatting for BigMath [Fixes GH-306]

  Based on a patch by @eLobato.
* ext/bigdecimal/lib/bigdecimal/math.rb: ditto


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@40840 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

3 files changed, 72 insertions, 26 deletions

diff --git a/ChangeLog b/ChangeLog
index cc939918d9..f8a402f43a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Mon May 20 05:58:12 2013  Zachary Scott  <zachary@zacharyscott.net>
+
+	* ext/bigdecimal/bigdecimal.c: Formatting for BigMath [Fixes GH-306]
+	  Based on a patch by @eLobato.
+	* ext/bigdecimal/lib/bigdecimal/math.rb: ditto
+
 Mon May 20 04:56:59 2013  Zachary Scott  <zachary@zacharyscott.net>
 
 	* lib/forwardable.rb: Forwardable examples in overview were broken
diff --git a/ext/bigdecimal/bigdecimal.c b/ext/bigdecimal/bigdecimal.c
index d6046f3744..06b3886eb5 100644
--- a/ext/bigdecimal/bigdecimal.c
+++ b/ext/bigdecimal/bigdecimal.c
@@ -2630,14 +2630,14 @@ BigDecimal_save_limit(VALUE self)
 }
 
 /* call-seq:
- * BigMath.exp(x, prec)
+ * BigMath.exp(decimal, numeric)    -> BigDecimal
  *
  * Computes the value of e (the base of natural logarithms) raised to the
- * power of x, to the specified number of digits of precision.
+ * power of +decimal+, to the specified number of digits of precision.
  *
- * If x is infinity, returns Infinity.
+ * If +decimal+ is infinity, returns Infinity.
  *
- * If x is NaN, returns NaN.
+ * If +decimal+ is NaN, returns NaN.
  */
 static VALUE
 BigMath_s_exp(VALUE klass, VALUE x, VALUE vprec)
@@ -2760,16 +2760,16 @@ BigMath_s_exp(VALUE klass, VALUE x, VALUE vprec)
 }
 
 /* call-seq:
- * BigMath.log(x, prec)
+ * BigMath.log(decimal, numeric)    -> BigDecimal
  *
- * Computes the natural logarithm of x to the specified number of digits of
- * precision.
+ * Computes the natural logarithm of +decimal+ to the specified number of
+ * digits of precision, +numeric+.
  *
- * If x is zero or negative, raises Math::DomainError.
+ * If +decimal+ is zero or negative, raises Math::DomainError.
  *
- * If x is positive infinity, returns Infinity.
+ * If +decimal+ is positive infinity, returns Infinity.
  *
- * If x is NaN, returns NaN.
+ * If +decimal+ is NaN, returns NaN.
  */
 static VALUE
 BigMath_s_log(VALUE klass, VALUE x, VALUE vprec)
@@ -3228,7 +3228,6 @@ Init_bigdecimal(void)
     rb_define_method(rb_cBigDecimal, "truncate",  BigDecimal_truncate, -1);
     rb_define_method(rb_cBigDecimal, "_dump", BigDecimal_dump, -1);
 
-    /* mathematical functions */
     rb_mBigMath = rb_define_module("BigMath");
     rb_define_singleton_method(rb_mBigMath, "exp", BigMath_s_exp, 2);
     rb_define_singleton_method(rb_mBigMath, "log", BigMath_s_log, 2);
diff --git a/ext/bigdecimal/lib/bigdecimal/math.rb b/ext/bigdecimal/lib/bigdecimal/math.rb
index 7289661fc2..4504ccb2b0 100644
--- a/ext/bigdecimal/lib/bigdecimal/math.rb
+++ b/ext/bigdecimal/lib/bigdecimal/math.rb
@@ -20,30 +20,40 @@ require 'bigdecimal'
 #
 # Example:
 #
-#   require "bigdecimal"
 #   require "bigdecimal/math"
 #
 #   include BigMath
 #
 #   a = BigDecimal((PI(100)/2).to_s)
-#   puts sin(a,100) # -> 0.10000000000000000000......E1
+#   puts sin(a,100) # => 0.10000000000000000000......E1
 #
 module BigMath
   module_function
 
-  # Computes the square root of x to the specified number of digits of
-  # precision.
+  # call-seq:
+  #   sqrt(decimal, numeric) -> BigDecimal
   #
-  # BigDecimal.new('2').sqrt(16).to_s
-  #  -> "0.14142135623730950488016887242096975E1"
+  # Computes the square root of +decimal+ to the specified number of digits of
+  # precision, +numeric+.
   #
-  def sqrt(x,prec)
+  #   BigMath::sqrt(BigDecimal.new('2'), 16).to_s
+  #   #=> "0.14142135623730950488016887242096975E1"
+  #
+  def sqrt(x, prec)
     x.sqrt(prec)
   end
 
-  # Computes the sine of x to the specified number of digits of precision.
+  # call-seq:
+  #   sin(decimal, numeric) -> BigDecimal
+  #
+  # Computes the sine of +decimal+ to the specified number of digits of
+  # precision, +numeric+.
+  #
+  # If +decimal+ is Infinity or NaN, returns NaN.
+  #
+  #   BigMath::sin(BigMath::PI(5)/4, 5).to_s
+  #   #=> "0.70710678118654752440082036563292800375E0"
   #
-  # If x is infinite or NaN, returns NaN.
   def sin(x, prec)
     raise ArgumentError, "Zero or negative precision for sin" if prec <= 0
     return BigDecimal("NaN") if x.infinite? || x.nan?
@@ -77,9 +87,17 @@ module BigMath
     neg ? -y : y
   end
 
-  # Computes the cosine of x to the specified number of digits of precision.
+  # call-seq:
+  #   cos(decimal, numeric) -> BigDecimal
+  #
+  # Computes the cosine of +decimal+ to the specified number of digits of
+  # precision, +numeric+.
+  #
+  # If +decimal+ is Infinity or NaN, returns NaN.
+  #
+  #   BigMath::cos(BigMath::PI(4), 16).to_s
+  #   #=> "-0.999999999999999999999999999999856613163740061349E0"
   #
-  # If x is infinite or NaN, returns NaN.
   def cos(x, prec)
     raise ArgumentError, "Zero or negative precision for cos" if prec <= 0
     return BigDecimal("NaN") if x.infinite? || x.nan?
@@ -113,9 +131,17 @@ module BigMath
     y
   end
 
-  # Computes the arctangent of x to the specified number of digits of precision.
+  # call-seq:
+  #   atan(decimal, numeric) -> BigDecimal
+  #
+  # Computes the arctangent of +decimal+ to the specified number of digits of
+  # precision, +numeric+.
+  #
+  # If +decimal+ is NaN, returns NaN.
+  #
+  #   BigMath::atan(BigDecimal.new('-1'), 16).to_s
+  #   #=> "-0.785398163397448309615660845819878471907514682065E0"
   #
-  # If x is NaN, returns NaN.
   def atan(x, prec)
     raise ArgumentError, "Zero or negative precision for atan" if prec <= 0
     return BigDecimal("NaN") if x.nan?
@@ -144,7 +170,15 @@ module BigMath
     y
   end
 
-  # Computes the value of pi to the specified number of digits of precision.
+  # call-seq:
+  #   PI(numeric) -> BigDecimal
+  #
+  # Computes the value of pi to the specified number of digits of precision,
+  # +numeric+.
+  #
+  #   BigMath::PI(10).to_s
+  #   #=> "0.3141592653589793238462643388813853786957412E1"
+  #
   def PI(prec)
     raise ArgumentError, "Zero or negative argument for PI" if prec <= 0
     n      = prec + BigDecimal.double_fig
@@ -181,8 +215,15 @@ module BigMath
     pi
   end
 
+  # call-seq:
+  #   E(numeric) -> BigDecimal
+  #
   # Computes e (the base of natural logarithms) to the specified number of
-  # digits of precision.
+  # digits of precision, +numeric+.
+  #
+  #   BigMath::E(10).to_s
+  #   #=> "0.271828182845904523536028752390026306410273E1"
+  #
   def E(prec)
     raise ArgumentError, "Zero or negative precision for E" if prec <= 0
     n    = prec + BigDecimal.double_fig