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ferret/pkg/runtime/expressions/member.go
2018-10-28 01:45:26 -04:00

57 lines
1.2 KiB
Go

package expressions
import (
"context"
"github.com/MontFerret/ferret/pkg/runtime/core"
"github.com/MontFerret/ferret/pkg/runtime/values"
)
type MemberExpression struct {
src core.SourceMap
variableName string
path []core.Expression
}
func NewMemberExpression(src core.SourceMap, variableName string, path []core.Expression) (*MemberExpression, error) {
if variableName == "" {
return nil, core.Error(core.ErrMissedArgument, "variable name")
}
if path == nil || len(path) == 0 {
return nil, core.Error(core.ErrMissedArgument, "path expressions")
}
return &MemberExpression{src, variableName, path}, nil
}
func (e *MemberExpression) Exec(ctx context.Context, scope *core.Scope) (core.Value, error) {
val, err := scope.GetVariable(e.variableName)
if err != nil {
return values.None, core.SourceError(
e.src,
err,
)
}
strPath := make([]core.Value, len(e.path))
for idx, exp := range e.path {
segment, err := exp.Exec(ctx, scope)
if err != nil {
return values.None, err
}
strPath[idx] = segment
}
out, err := values.GetIn(val, strPath)
if err != nil {
return values.None, core.SourceError(e.src, err)
}
return out, nil
}