Ticket #114: pow-expr2.patch

Source/BackEndClr/SharpGenerator.cobra

@@ -4080 +4080 @@
             on 'STAR_EQUALS'
                 op = '*='
             on 'STARSTAR_EQUALS'
-                #op = 'CobraLangInternal.CobraImp.PowerToEquals('
-                op = 'System.Math.Pow('
+                op = 'CobraLangInternal.CobraImp.PowerTo('
+                #op = 'System.Math.Pow('
             on 'SLASH_EQUALS'
                 op = '/='  # TODO: finish this
             on 'SLASHSLASH_EQUALS'
@@ -4091 +4091 @@
             else
                 throw FallThroughException(_op)
         assert op.length
-        if op.length==2
+        if op.length==2   # One of C# augAssign operators
             _left.writeSharpDef(sw)
             sw.write(op)
             _right.writeSharpDef(sw)
-        else
+        else            # method call assumed to return value
+            _left.writeSharpDef(sw)
+            sw.write(" = " )  
             sw.write(op)  # ex: 'CobraLangInternal.CobraImp.Foo('
             _left.writeSharpDef(sw)
             sw.write(sep)
@@ -4233 +4235 @@
             on 'STAR'
                 op = '*'
             on 'STARSTAR'
-                #op = 'CobraLangInternal.CobraImp.PowerTo('
-                op = 'System.Math.Pow('
-                if _left.isKindOf(intType) and _right.isKindOf(intType)
-                    pre = '(' + .compiler.intType.sharpRef + ')'
+                op = 'CobraLangInternal.CobraImp.PowerTo('
+                #op = 'System.Math.Pow('
+                #if _left.isKindOf(intType) and _right.isKindOf(intType)
+                #   pre = '(' + .compiler.intType.sharpRef + ')'
             on 'SLASH'
                 op = '/'
                 if _left.isKindOf(intType) and _right.isKindOf(intType)

Source/Cobra.Lang/Native.cs

@@ -1103 +1103 @@
         return a / b;
     }
 
+    static public int PowerTo(int a, int b) {
+        // return (int) Math.Pow(a, b)
+                //  below is about 25x faster than calling Math.Pow
+        if (b == 0)
+            return 1;
+        int r = 0;
+        if ( b > 0 ) {
+            r = a;
+            while (b > 1) {
+                r = r * a;
+                b = b - 1;
+                }
+        }
+        return r;
+    }
+
+    static public  Double PowerTo(Double a, Double b) {
+        return  System.Math.Pow(a, b);
+    }
+
     static public string RunAndCaptureAllOutput(object process) {
         // CC: change to extension method on Process class
         System.Diagnostics.Process proc = (System.Diagnostics.Process)process;

Tests/100-basics/930-pow-expr.cobra

@@ +1 @@
+use System.Diagnostics
+
 class ToThePower
 
-    def main
+    def main is shared
+        .powExpr
+        .powAugAssign
+#       .time
+    
+    def powExpr is shared
         for i, answer in [[2, 100], [3, 1_000], [4, 10_000], [5, 100_000]]
             x = 10 ** i
             assert x inherits int  # .warning. The expression is always of type "int"
@@ -18 +25 @@
             
         f = 1.1f ** 3f  # 1.331
         assert f >= 1.331f and f < 1.3311f
+    
+        assert 2 ** 0 == 1
+        assert 2 ** 1 == 2
+    
+        assert 2f ** 0f == 1f
+        assert 2f ** 1f == 2f
+    
+        assert 2f ** 0 == 1f
+        assert 2f ** 1 == 2f
+        assert 2f ** 2 == 4f
+        
+        assert 2f ** -2 == 0.25f
+        assert 2 ** -2 == 0     # shld this throw instead ?  
+        
+    def powAugAssign is shared
+        for i, answer in [[2, 100], [3, 1_000], [4, 10_000], [5, 100_000]]
+            x = 10 
+            x **= i
+            assert x == answer
+    
+        for j, answerf in [[2f, 9f], [3f, 27f], [4f, 81f], [5f, 243f]]  
+            z = 3f
+            z **= j
+            assert z == answerf
+            
+        #int raised  int
+        y=2
+        y **= 0 
+        assert y == 1
+        y **= 1 
+        assert y == 1
+        y=2
+        y **= 1 
+        assert y == 2
+        
+        # float raised float
+        f = 2f
+        f **= 0f 
+        assert f == 1f
+        f **= 1f
+        assert f == 1f
+
+        f = 2f
+        f **= 1f
+        assert f == 2f
+        f **= 2f
+        assert f == 4f
+    
+        # float raised int
+        f = 2f
+        f **= 0 
+        assert f == 1f
+
+        f = 2f
+        f **= 1
+        assert f == 2f
+        f **= 2
+        assert f == 4f
+        
+        # {float, int} raised negatives
+        f = 2f
+        f **= -2
+        assert f == 0.25f
+        
+        y = 2
+        y **= -2
+        assert y == 0  
+        
+    def time is shared
+        count= 1_000_000
+        sw = Stopwatch()
+        sw.start
+        for i in count
+            c = 10 ** 3
+        sw.stop
+        t1 = sw.elapsedMilliseconds
+        print t1/count 
+        sw.reset
+    
+        sw.start
+        for i in count
+            c1 = 10f ** 3f
+        sw.stop
+        t1 = sw.elapsedMilliseconds
+        print t1/count 
+        sw.reset
+    
+/#
+        sw.start
+        for i in count
+            c2 = (10 to float) ** (3 to float)
+        sw.stop
+        t1 = sw.elapsedMilliseconds
+        print t1/count 
+#/      
+        CobraCore.noOp(c)
+        CobraCore.noOp(c1)