Rename the Length methods Len to follow GO standart

pkg/obieval/language.go

@@ -0,0 +1,21 @@
+package obieval
+
+import (
+	"git.metabarcoding.org/lecasofts/go/obitools/pkg/goutils"
+	"github.com/PaesslerAG/gval"
+)
+
+var OBILang = gval.NewLanguage(
+	gval.Full(),
+	gval.Function("len", func(args ...interface{}) (interface{}, error) {
+		length := goutils.Len(args[0])
+		return (float64)(length), nil
+	}),
+	gval.Function("ismap", func(args ...interface{}) (interface{}, error) {
+		ismap := goutils.IsAMap(args[0])
+		return ismap, nil
+	}))
+
+func Expression(expression string) (gval.Evaluable, error) {
+	return OBILang.NewEvaluable(expression)
+}