# Swapped syntax for Natural numbers and Integers¶

Migrate your code to support the change in syntax for

`Natural`

numbers and`Integer`

s

On May 7, 2018 the language standard changed to swap the syntax for `Natural`

numbers and `Integer`

s. This section describes what changed and how to migrate your code.

## Changes¶

Before the change, the standard specified that:

literal numbers with a leading

`+`

were`Natural`

numbers,literal numbers without a leading sign were

`Integer`

s, and:literal numbers with a leading

`-`

were`Integer`

s.

In other words:

```
-- Before
+2 : Natural
2 : Integer
-2 : Integer
```

After the change, the standard specifies that:

literal numbers without a leading sign are

`Natural`

numbers, and:literal numbers with a leading sign (both

`+`

and`-`

) are`Integer`

s.

In other words:

```
-- After
2 : Natural
+2 : Integer
-2 : Integer
```

Additionally, `Natural/show`

was changed to render `Natural`

numbers without the leading sign and `Integer/show`

was changed to render non-negative `Integer`

s with a leading `+`

sign:

```
-- Before
Natural/show +2 = "+2"
Integer/show 2 = "2"
Integer/show -2 = "-2"
```

```
-- After
Natural/show 2 = "2"
Integer/show +2 = "+2"
Integer/show -2 = "-2"
```

## Migration¶

To migrate code you need to:

Remove the leading

`+`

from all`Natural`

number literalsAdd a leading

`+`

to all non-negative`Integer`

literalsReplace

`Natural/show n`

with`"+${Natural/show n}"`

Replace

`Integer/show (Natural/toInteger n)`

with`Natural/show n`

Also, you can no longer render `Integer`

s without a leading `+`

or `-`

sign