added MustEvaluate which turns panics into errors + tests

evaluator.go

@@ -1,6 +1,8 @@
 package goval
 
 import (
+	"fmt"
+
 	"github.com/maja42/goval/internal"
 )
 
@@ -30,3 +32,24 @@ type ExpressionFunction = func(args ...interface{}) (interface{}, error)
 func (e *Evaluator) Evaluate(str string, variables map[string]interface{}, functions map[string]ExpressionFunction) (result interface{}, err error) {
 	return internal.Evaluate(str, variables, functions)
 }
+
+// MustEvaluate evaluates the given expression string.
+//
+// Never panics: instead turns any panic into an error (e.g., division by zero).
+//
+// Optionally accepts a list of variables (accessible but not modifiable from within expressions).
+//
+// Optionally accepts a list of expression functions (can be called from within expressions).
+//
+// Returns the resulting object or an error.
+//
+// Stateless. Can be called concurrently. If expression functions modify variables, concurrent execution requires additional synchronization.
+func (e *Evaluator) MustEvaluate(str string, variables map[string]interface{}, functions map[string]ExpressionFunction) (result interface{}, err error) {
+	defer func() {
+		if r := recover(); r != nil {
+			result = nil
+			err = fmt.Errorf("%v", r)
+		}
+	}()
+	return internal.Evaluate(str, variables, functions)
+}

evaluator_test.go

@@ -1,8 +1,9 @@
 package goval
 
 import (
-	"github.com/stretchr/testify/assert"
 	"testing"
+
+	"github.com/stretchr/testify/assert"
 )
 
 func Test_Evaluator(t *testing.T) {
@@ -20,3 +21,22 @@ func Test_Evaluator(t *testing.T) {
 	assert.NoError(t, err)
 	assert.Equal(t, 42, result)
 }
+
+func Test_MustEvaluator(t *testing.T) {
+	variables := map[string]interface{}{
+		"var": 21,
+	}
+	functions := map[string]ExpressionFunction{
+		"func": func(args ...interface{}) (interface{}, error) {
+			return args[0], nil
+		},
+	}
+
+	evaluator := NewEvaluator()
+	result, err := evaluator.MustEvaluate("func( var ) + 21", variables, functions)
+	assert.NoError(t, err)
+	assert.Equal(t, 42, result)
+	result, err = evaluator.MustEvaluate("1/0", variables, functions)
+	assert.Nil(t, result)
+	assert.NotNil(t, err)
+}