mruby-math: define and use `Math::DomainError`

Domain errors are detected as per ISO C99 and may differ from CRuby.

mrbgems/mruby-math/src/math.c

@@ -9,8 +9,14 @@
 
 #include <math.h>
 
-#define domain_error(msg) \
-    mrb_raise(mrb, E_RANGE_ERROR, "Numerical argument is out of domain - " #msg)
+static void
+domain_error(mrb_state *mrb, const char *func)
+{
+  struct RClass *math = mrb_module_get(mrb, "Math");
+  struct RClass *domainerror = mrb_class_get_under(mrb, math, "DomainError");
+  mrb_value str = mrb_str_new_cstr(mrb, func);
+  mrb_raisef(mrb, domainerror, "Numerical argument is out of domain - %S", str);
+}
 
 /* math functions not provided by Microsoft Visual C++ 2012 or older */
 #if defined _MSC_VER && _MSC_VER < 1800
@@ -172,6 +178,9 @@ math_asin(mrb_state *mrb, mrb_value obj)
   mrb_float x;
 
   mrb_get_args(mrb, "f", &x);
+  if (x < -1.0 || x > 1.0) {
+    domain_error(mrb, "asin");
+  }
   x = asin(x);
 
   return mrb_float_value(mrb, x);
@@ -189,6 +198,9 @@ math_acos(mrb_state *mrb, mrb_value obj)
   mrb_float x;
 
   mrb_get_args(mrb, "f", &x);
+  if (x < -1.0 || x > 1.0) {
+    domain_error(mrb, "acos");
+  }
   x = acos(x);
 
   return mrb_float_value(mrb, x);
@@ -334,6 +346,9 @@ math_acosh(mrb_state *mrb, mrb_value obj)
   mrb_float x;
 
   mrb_get_args(mrb, "f", &x);
+  if (x < 1.0) {
+    domain_error(mrb, "acosh");
+  }
   x = acosh(x);
 
   return mrb_float_value(mrb, x);
@@ -351,6 +366,9 @@ math_atanh(mrb_state *mrb, mrb_value obj)
   mrb_float x;
 
   mrb_get_args(mrb, "f", &x);
+  if (x < -1.0 || x > 1.0) {
+    domain_error(mrb, "atanh");
+  }
   x = atanh(x);
 
   return mrb_float_value(mrb, x);
@@ -404,8 +422,14 @@ math_log(mrb_state *mrb, mrb_value obj)
   int argc;
 
   argc = mrb_get_args(mrb, "f|f", &x, &base);
+  if (x < 0.0) {
+    domain_error(mrb, "log");
+  }
   x = log(x);
   if (argc == 2) {
+    if (base < 0.0) {
+      domain_error(mrb, "log");
+    }
     x /= log(base);
   }
   return mrb_float_value(mrb, x);
@@ -429,6 +453,9 @@ math_log2(mrb_state *mrb, mrb_value obj)
   mrb_float x;
 
   mrb_get_args(mrb, "f", &x);
+  if (x < 0.0) {
+    domain_error(mrb, "log2");
+  }
   x = log2(x);
 
   return mrb_float_value(mrb, x);
@@ -451,6 +478,9 @@ math_log10(mrb_state *mrb, mrb_value obj)
   mrb_float x;
 
   mrb_get_args(mrb, "f", &x);
+  if (x < 0.0) {
+    domain_error(mrb, "log10");
+  }
   x = log10(x);
 
   return mrb_float_value(mrb, x);
@@ -469,6 +499,9 @@ math_sqrt(mrb_state *mrb, mrb_value obj)
   mrb_float x;
 
   mrb_get_args(mrb, "f", &x);
+  if (x < 0.0) {
+    domain_error(mrb, "sqrt");
+  }
   x = sqrt(x);
 
   return mrb_float_value(mrb, x);
@@ -624,6 +657,8 @@ mrb_mruby_math_gem_init(mrb_state* mrb)
   struct RClass *mrb_math;
   mrb_math = mrb_define_module(mrb, "Math");
 
+  mrb_define_class_under(mrb, mrb_math, "DomainError", mrb->eStandardError_class);
+
 #ifdef M_PI
   mrb_define_const(mrb, mrb_math, "PI", mrb_float_value(mrb, M_PI));
 #else