Make "decimal" functions more consistent

In GDScript, rename "decimals" to "step_decimals". In C#, add "StepDecimals", but keep the old functionality in a method called "DecimalCount".

core/math/expression.cpp

@@ -64,6 +64,7 @@ const char *Expression::func_name[Expression::FUNC_MAX] = {
 	"is_inf",
 	"ease",
 	"decimals",
+	"step_decimals",
 	"stepify",
 	"lerp",
 	"inverse_lerp",
@@ -149,6 +150,7 @@ int Expression::get_func_argument_count(BuiltinFunc p_func) {
 		case MATH_ISNAN:
 		case MATH_ISINF:
 		case MATH_DECIMALS:
+		case MATH_STEP_DECIMALS:
 		case MATH_SEED:
 		case MATH_RANDSEED:
 		case MATH_DEG2RAD:
@@ -365,6 +367,11 @@ void Expression::exec_func(BuiltinFunc p_func, const Variant **p_inputs, Variant
 			VALIDATE_ARG_NUM(0);
 			*r_return = Math::step_decimals((double)*p_inputs[0]);
 		} break;
+		case MATH_STEP_DECIMALS: {
+
+			VALIDATE_ARG_NUM(0);
+			*r_return = Math::step_decimals((double)*p_inputs[0]);
+		} break;
 		case MATH_STEPIFY: {
 
 			VALIDATE_ARG_NUM(0);

core/math/expression.h

@@ -62,6 +62,7 @@ public:
 		MATH_ISINF,
 		MATH_EASE,
 		MATH_DECIMALS,
+		MATH_STEP_DECIMALS,
 		MATH_STEPIFY,
 		MATH_LERP,
 		MATH_INVERSE_LERP,

doc/classes/@GDScript.xml

@@ -264,11 +264,7 @@
 			<argument index="0" name="step" type="float">
 			</argument>
 			<description>
-				Returns the position of the first non-zero digit, after the decimal point.
+				Deprecated alias for "[method step_decimals]". 
-				[codeblock]
-				# n is 2
-				n = decimals(0.035)
-				[/codeblock]
 			</description>
 		</method>
 		<method name="dectime">
@@ -1023,6 +1019,23 @@
 				[/codeblock]
 			</description>
 		</method>
+		<method name="step_decimals">
+			<return type="float">
+			</return>
+			<argument index="0" name="step" type="float">
+			</argument>
+			<description>
+				Returns the position of the first non-zero digit, after the decimal point.
+				[codeblock]
+				# n is 0
+				n = step_decimals(5)
+				# n is 4
+				n = step_decimals(1.0005)
+				# n is 9
+				n = step_decimals(0.000000005)
+				[/codeblock]
+			</description>
+		</method>
 		<method name="stepify">
 			<return type="float">
 			</return>

modules/gdscript/gdscript_functions.cpp

@@ -72,6 +72,7 @@ const char *GDScriptFunctions::get_func_name(Function p_func) {
 		"is_zero_approx",
 		"ease",
 		"decimals",
+		"step_decimals",
 		"stepify",
 		"lerp",
 		"inverse_lerp",
@@ -339,6 +340,13 @@ void GDScriptFunctions::call(Function p_func, const Variant **p_args, int p_arg_
 			VALIDATE_ARG_COUNT(1);
 			VALIDATE_ARG_NUM(0);
 			r_ret = Math::step_decimals((double)*p_args[0]);
+			ERR_EXPLAIN("GDScript method 'decimals' is deprecated and has been renamed to 'step_decimals', please update your code accordingly.");
+			WARN_DEPRECATED
+		} break;
+		case MATH_STEP_DECIMALS: {
+			VALIDATE_ARG_COUNT(1);
+			VALIDATE_ARG_NUM(0);
+			r_ret = Math::step_decimals((double)*p_args[0]);
 		} break;
 		case MATH_STEPIFY: {
 			VALIDATE_ARG_COUNT(2);
@@ -1452,6 +1460,7 @@ bool GDScriptFunctions::is_deterministic(Function p_func) {
 		case MATH_ISINF:
 		case MATH_EASE:
 		case MATH_DECIMALS:
+		case MATH_STEP_DECIMALS:
 		case MATH_STEPIFY:
 		case MATH_LERP:
 		case MATH_INVERSE_LERP:
@@ -1626,7 +1635,12 @@ MethodInfo GDScriptFunctions::get_info(Function p_func) {
 		} break;
 		case MATH_DECIMALS: {
 			MethodInfo mi("decimals", PropertyInfo(Variant::REAL, "step"));
-			mi.return_val.type = Variant::REAL;
+			mi.return_val.type = Variant::INT;
+			return mi;
+		} break;
+		case MATH_STEP_DECIMALS: {
+			MethodInfo mi("step_decimals", PropertyInfo(Variant::REAL, "step"));
+			mi.return_val.type = Variant::INT;
 			return mi;
 		} break;
 		case MATH_STEPIFY: {

modules/gdscript/gdscript_functions.h

@@ -63,6 +63,7 @@ public:
 		MATH_ISZEROAPPROX,
 		MATH_EASE,
 		MATH_DECIMALS,
+		MATH_STEP_DECIMALS,
 		MATH_STEPIFY,
 		MATH_LERP,
 		MATH_INVERSE_LERP,

modules/mono/glue/Managed/Files/Mathf.cs

@@ -79,14 +79,27 @@ namespace Godot
             return (real_t)Math.Cosh(s);
         }
 
-        public static int Decimals(real_t step)
+        public static int StepDecimals(real_t step)
         {
-            return Decimals((decimal)step);
+            double[] sd = new double[] {
-        }
+                0.9999,
-
+                0.09999,
-        public static int Decimals(decimal step)
+                0.009999,
-        {
+                0.0009999,
-            return BitConverter.GetBytes(decimal.GetBits(step)[3])[2];
+                0.00009999,
+                0.000009999,
+                0.0000009999,
+                0.00000009999,
+                0.000000009999,
+            };
+            double abs = Mathf.Abs(step);
+            double decs = abs - (int)abs; // Strip away integer part
+            for (int i = 0; i < sd.Length; i++) {
+                if (decs >= sd[i]) {
+                    return i;
+                }
+            }
+            return 0;
         }
 
         public static real_t Deg2Rad(real_t deg)

modules/mono/glue/Managed/Files/MathfEx.cs

@@ -21,6 +21,16 @@ namespace Godot
         public const real_t Epsilon = 1e-06f;
 #endif
 
+        public static int DecimalCount(real_t s)
+        {
+            return DecimalCount((decimal)s);
+        }
+
+        public static int DecimalCount(decimal s)
+        {
+            return BitConverter.GetBytes(decimal.GetBits(s)[3])[2];
+        }
+
         public static int CeilToInt(real_t s)
         {
             return (int)Math.Ceiling(s);