previous iteration in foreach

Not sure about the exact requirements. The following code snippet might be helpful:

a!localVariables(
  local!data: {"A","B","C","D"},
  a!forEach(
    items: local!data,
    expression: a!localVariables(
      local!previousData: if(not(fv!isFirst), index(local!data, fv!index-1), null),
      a!map(data:fv!item, previous: local!previousData)
    )
  )
)

I need to sort a list, but if there are two equal values ​​they have the same order,
with the array
{
name:"aaaaa", valor:2
name:"bbbbb", valor:10
name:"ccccc", valor:10
name:"ddddd", valor:10
name:"eeeee", valor:45
}
get as a result
{
name:"aaaaa", pos:1
name:"bbbbb", pos:2
name:"ccccc", pos:2
name:"ddddd", pos:2
name:"eeeee", pos:3
}

I am trying to save the pos outside of the foreach in a local variable, or recover the value saved in pos of the previous item

I need to sort a list, but if there are two equal values ​​they have the same order,
with the array
{
name:"aaaaa", valor:2
name:"bbbbb", valor:10
name:"ccccc", valor:10
name:"ddddd", valor:10
name:"eeeee", valor:45
}
get as a result
{
name:"aaaaa", pos:1
name:"bbbbb", pos:2
name:"ccccc", pos:2
name:"ddddd", pos:2
name:"eeeee", pos:3
}

I am trying to save the pos outside of the foreach in a local variable, or recover the value saved in pos of the previous item

I did not understand what you are trying to implemented... Could you give us more information? What it would the expected output?