builtin-base.go: new eval() function

builtin-base.go

@@ -8,6 +8,7 @@ import (
 	"fmt"
 	"math"
 	"strconv"
+	"strings"
 )
 
 const (
@@ -188,6 +189,30 @@ func fractFunc(ctx ExprContext, name string, args map[string]any) (result any, e
 // 	return
 // }
 
+func evalFunc(ctx ExprContext, name string, args map[string]any) (result any, err error) {
+	if source, ok := args[ParamSource].(string); ok {
+		var expr Expr
+
+		parser := NewParser()
+		if ctx == nil {
+			ctx = NewSimpleStore()
+		}
+
+		r := strings.NewReader(source)
+		scanner := NewScanner(r, DefaultTranslations())
+
+		if expr, err = parser.Parse(scanner); err == nil {
+			CtrlEnable(ctx, control_export_all)
+			result, err = expr.Eval(ctx)
+		}
+	} else {
+		err = ErrWrongParamType(name, ParamSource, TypeString, args[ParamSource])
+	}
+	return
+}
+
+//// import
+
 func ImportBuiltinsFuncs(ctx ExprContext) {
 	anyParams := []ExprFuncParam{
 		NewFuncParam(ParamValue),
@@ -211,6 +236,10 @@ func ImportBuiltinsFuncs(ctx ExprContext) {
 		NewFuncParam(ParamValue),
 		NewFuncParamFlagDef(ParamDenominator, PfDefault, int64(1)),
 	})
+
+	ctx.RegisterFunc("eval", NewGolangFunctor(evalFunc), TypeAny, []ExprFuncParam{
+		NewFuncParam(ParamSource),
+	})
 }
 
 func init() {

t_builtin-base_test.go

@@ -56,11 +56,12 @@ func TestFuncBase(t *testing.T) {
 		/*  42 */ {`dec(false)`, float64(0), nil},
 		/*  43 */ {`dec(1:2)`, float64(0.5), nil},
 		/*  44 */ {`dec([1])`, nil, `dec(): can't convert list to float`},
+		/*  45 */ {`eval("a=3"); a`, int64(3), nil},
 		// /*  45 */ {`string([1])`, nil, `string(): can't convert list to string`},
 	}
 
 	t.Setenv("EXPR_PATH", ".")
 
-	// runTestSuiteSpec(t, section, inputs, 30)
+	// runTestSuiteSpec(t, section, inputs, 45)
 	runTestSuite(t, section, inputs)
 }