Added int caster to gval functions

pkg/expr/func_num.go

@@ -1,10 +1,12 @@
 package expr
 
 import (
-	"github.com/PaesslerAG/gval"
-	"github.com/pkg/errors"
 	"math"
 	"math/rand"
+
+	"github.com/PaesslerAG/gval"
+	"github.com/pkg/errors"
+	"github.com/spf13/cast"
 )
 
 func NumericFunctions() []gval.Language {
@@ -21,6 +23,7 @@ func NumericFunctions() []gval.Language {
 		gval.Function("sum", sum),
 		gval.Function("average", average),
 		gval.Function("random", random),
+		gval.Function("int", toInt64),
 	}
 }
 
@@ -141,3 +144,7 @@ func random(v ...float64) (out float64, err error) {
 	out = from + rand.Float64()*(to-from)
 	return
 }
+
+func toInt64(aa interface{}) (i int64) {
+	return cast.ToInt64(aa)
+}

pkg/expr/func_num_test.go

@@ -90,3 +90,24 @@ func Example_randomWithTwoInput() {
 	// output:
 	// 1
 }
+
+func Example_castStringToInt() {
+	eval(`int("abc")`, nil)
+
+	// output:
+	// 0
+}
+
+func Example_castStringNumberToInt() {
+	eval(`int("42690")`, nil)
+
+	// output:
+	// 42690
+}
+
+func Example_castFloatToInt() {
+	eval(`int("42.690")`, nil)
+
+	// output:
+	// 0
+}