# How to use strings in Ada?
**URL:** https://forum.ada-lang.io/t/how-to-use-strings-in-ada/1317
**Category:** General
**Tags:** ada
**Created:** [October 12, 2024, 7:37pm UTC](https://forum.ada-lang.io/t/how-to-use-strings-in-ada/1317 "2024-10-12T19:37:39Z")
**Posts on this page:** 11
**Page:** 2
### Author:  [@simonjwright](https://forum.ada-lang.io/u/simonjwright)
#### Post date: [October 15, 2024, 9:32pm UTC](https://forum.ada-lang.io/t/how-to-use-strings-in-ada/1317/22 "2024-10-15T21:32:50Z")
There’s nothing wrong with heap allocation; for a short-lived not-too-large program, let the OS clean up on program exit.
For a long-lived program, deallocation needs to be taken care of. Most of the time, you can rely on well-written libraries, like `Ada.Strings.Unbounded` or the indefinite containers.
---
### Author:  [@gast](https://forum.ada-lang.io/u/gast)
#### Post date: [October 15, 2024, 10:34pm UTC](https://forum.ada-lang.io/t/how-to-use-strings-in-ada/1317/23 "2024-10-15T22:34:07Z")
> Of course, in Ada you can have a specially designed memory pool to improve performance like mark-and-release pool.
Is there any sample code for such an implementation?
---
### Author:  [@stevelitt](https://forum.ada-lang.io/u/stevelitt)
#### Post date: [October 15, 2024, 11:51pm UTC](https://forum.ada-lang.io/t/how-to-use-strings-in-ada/1317/24 "2024-10-15T23:51:24Z")
[dmitry-kazakov] How would I implement your type Roman\_Latin if I wanted UTF-8 characters? Thanks.
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### Author:  [@AJ-Ianozi](https://forum.ada-lang.io/u/AJ-Ianozi)
#### Post date: [October 16, 2024, 2:22am UTC](https://forum.ada-lang.io/t/how-to-use-strings-in-ada/1317/25 "2024-10-16T02:22:11Z")
Coincidentally @dmitry-kazakov Has written in one of the most influential string libraries with utf8 support in Ada back in the day, [Strings\_Edit](http://www.dmitry-kazakov.de/ada/strings_edit.htm), part of The Goliath known as [Simple Components](http://www.dmitry-kazakov.de/ada/components.htm).
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### Author:  [@jere](https://forum.ada-lang.io/u/jere)
#### Post date: [October 16, 2024, 2:33am UTC](https://forum.ada-lang.io/t/how-to-use-strings-in-ada/1317/26 "2024-10-16T02:33:38Z")
> [@gast](#):
>
> Is there any sample code for such an implementation?
You could check out dmitry’s at: [Simple components for Ada](http://www.dmitry-kazakov.de/ada/components.htm#Pools_etc)
---
### Author:  [@dmitry-kazakov](https://forum.ada-lang.io/u/dmitry-kazakov)
#### Post date: [October 16, 2024, 11:49am UTC](https://forum.ada-lang.io/t/how-to-use-strings-in-ada/1317/27 "2024-10-16T11:49:57Z")
That is a way different question. If you wanted an enumeration type encoded in a specific way, e.g. UTF-8 then Ada has representation clause for that:
```ada
type Roman_Latin is
( ' ','a','b','c','d','e','f','g','h','i','j','k','l',
'm','n','o','p','q','r','s','t','v','x','y','z'
);
for Roman_Latin use
( 'a' => 97, 'b' => 98, 'c' => 99, 'd' => 100,
'e' => 101, 'f' => 102, 'g' => 103, 'h' => 104,
'i' => 105, 'j' => 106, 'k' => 107, 'l' => 108,
'm' => 109, 'n' => 110, 'o' => 111, 'p' => 112,
'q' => 113, 'r' => 114, 's' => 115, 't' => 116,
'v' => 117, 'x' => 118, 'y' => 119, 'z' => 120,
' ' => 32
);
type Roman_String is array (Positive range <>) of Roman_Latin;
A : constant Roman_String := "veni vidi vici";
```
Here Roman\_Latin characters have Unicode code points as values.
What you cannot do is to make Roman\_Latin a subtype of Character or Wide\_Character. The Ada type system supports only range constraints, no holes.
---
### Author:  [@evanescente-ondine](https://forum.ada-lang.io/u/evanescente-ondine)
#### Post date: [October 16, 2024, 12:42pm UTC](https://forum.ada-lang.io/t/how-to-use-strings-in-ada/1317/28 "2024-10-16T12:42:04Z")
I think it’s bad form… Whenever I can reasonably predict a size, or the number of iterations of a loop a problem requires, I beat myself until I got the algorithm perfect. Isn’t this similar to the discussion over garbage collection ? I fear some practices make us lazy then we wonder why lightning fast complete graphical OSes used to fit on a few Mbs.
---
### Author:  [@OneWingedShark](https://forum.ada-lang.io/u/OneWingedShark)
#### Post date: [October 16, 2024, 11:44pm UTC](https://forum.ada-lang.io/t/how-to-use-strings-in-ada/1317/29 "2024-10-16T23:44:06Z")
> [@dmitry-kazakov](#):
>
> What you cannot do is to make Roman\_Latin a subtype of Character or Wide\_Character. The Ada type system supports only range constraints, no holes.
IIRC, you _can_ do that with the `Static_Predicate`.
```ada
-- Subtype renaming for continent switching of subtype derivation.
Subtype Code_Points is Wide_Wide_Character;
-- Subtypes defining the parts.
Subtype Upper is Code_Points range 'A'..'Z';
Subtype Lower is Code_Points range 'a'..'z';
Subtype Digit is Code_Points range '0'..'9';
Subtype Other is Code_Points
with Static_Predicate => ' ' | '.' | ',' | '?' | '(' | ')' | '"' | ''' | ':';
-- New type.
Type New_Roman_Latin is new Code_Points
with Static_Predicate => Upper | Lower | Digit | Other;
```
---
### Author:  [@dmitry-kazakov](https://forum.ada-lang.io/u/dmitry-kazakov)
#### Post date: [October 17, 2024, 7:30am UTC](https://forum.ada-lang.io/t/how-to-use-strings-in-ada/1317/30 "2024-10-17T07:30:18Z")
Yes, I forgot that. Then it would be:
```ada
subtype Roman_Latin is Character
with Static_Predicate => Roman_Latin in
' '|'a'|'b'|'c'|'d'|'e'|'f'|'g'|'h'|'i'|'j'|'k'|'l'|
'm'|'n'|'o'|'p'|'q'|'r'|'s'|'t'|'v'|'x'|'y'|'z';
```
---
### Author:  [@OneWingedShark](https://forum.ada-lang.io/u/OneWingedShark)
#### Post date: [October 17, 2024, 6:25pm UTC](https://forum.ada-lang.io/t/how-to-use-strings-in-ada/1317/31 "2024-10-17T18:25:36Z")
You can simplify that:
```ada
subtype Roman_Latin is Character
with Static_Predicate => Roman_Latin in ' '|'a'..'z';
```
---
### Author:  [@dmitry-kazakov](https://forum.ada-lang.io/u/dmitry-kazakov)
#### Post date: [October 17, 2024, 6:59pm UTC](https://forum.ada-lang.io/t/how-to-use-strings-in-ada/1317/32 "2024-10-17T18:59:25Z")
Latin alphabet has no U and W.
```ada
subtype Roman_Latin is Character
with Static_Predicate => Roman_Latin in
' ' | 'a'..'t'|'v'|'x'..'z';
```
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