Strings Library #12

bitzoic · 2022-08-03T21:01:44Z

Type of change

New feature

Changes

The following changes have been made:

Add Basic String library with the following functionality:
- as_bytes: Returns the stored string as bytes
- capacity: Returns the capacity allocated for the string
- clear: Truncates the string
- from_utf8: Takes a Vec and returns a String
- insert: Inserts an element at an index
- is_empty: Returns true if the string is empty
- len: Returns the length of the string
- new: Creates an empty string
- nth: Returns the element at the specified index
- pop: Removes and returns the last element of the string
- push: Appends to the end of the string
- remove: Removes an element at the specified index
- with_capacity: Creates a string with a specific capacity

Notes

More advanced features may be added later such as appending another string. This should likely be done with the Vec in the standard library and not with the string stuct.
A StorageString should be considered.
There is currently no relation between str and String. This is due to the compiler's handling of str.
The naming convention of functions is taken from Rust's String.

Related Issues

Closes #11

SwayStar123 · 2022-09-28T16:29:06Z

features like lower and upper might be useful to normalize inputs

Braqzen

Lots of suggestions about conveying information. Take it as you see fit. If any of my suggestions seem like an improvement then I suggest to not just copy and paste them in since I have put some thought into them but more careful wording may be selected.

README.md

sway_libs/src/string/string.sw

sway_libs/src/string/SPECIFICATION.md

matt-user

Can we use the string library with chars such as 'a' ? If so I would like to see some tests using characters instead of numbers

matt-user · 2022-10-06T17:44:41Z

sway_libs/src/string/README.md

+
+For more information please see the [specification](./SPECIFICATION.md).
+
+> **Note** There is currently no way to convert a `str` to a `String`.


If a str cannot be iterated over than I would agree with this note as Braqzen has noted as well. Did you mean perhaps to say an str cannot be casted to a String? IMO you should be able to do let s1: String = String::from("this is an str");

I don't believe this will be possible until type constraints are implemented. I think that is part of the declaration engine which afaik @emilyaherbert and @tritao are working on?

sway_libs/src/string/README.md

sway_libs/src/string/SPECIFICATION.md

bitzoic · 2022-10-06T19:06:42Z

Can we use the string library with chars such as 'a' ? If so I would like to see some tests using characters instead of numbers

Character in Sway do not exist. There is an issue that has been proposed here

Centril

Perhaps we only want to start off with the interface, but then we should state that this does no validation and essentially is just Vec<u8> (which Rust's String is also backed by, but the API is unicode-aware).

Centril · 2022-10-06T23:00:51Z

sway_libs/src/string/string.sw

+    /// Converts a vector of bytes to a `String`.
+    /// 
+    /// # Arguments
+    /// 
+    /// * `bytes` - The vector of `u8` bytes which will be converted into a `String`.
+    pub fn from_utf8(bytes: Vec<u8>) -> String {
+        String { bytes }
+    }
+
+    /// Inserts a byte at the index within the `String`.
+    /// 
+    /// # Arguments
+    /// 
+    /// * `byte` - The element which will be added to the `String`.
+    /// * `index` - The position in the `String` where the element will be inserted.
+    pub fn insert(self, byte: u8, index: u64) {
+        self.bytes.insert(index, byte);
+    }


These functions, as well as push, do not seem to be "sound" with respect to the stated purpose of String:

String is used for dynamic length strings that are UTF-8 encoded.

To start with, from_utf8 does no validation that the byte array actually is valid UTF-8. It might not be.
Then, let's assume that your string is valid. This can be broken by insertting bad bytes. Similarly, you can push the bad bytes onto the hitherto valid string.

Yes absolutely this is correct, my documentation is definitely misinforming in regards to this.

Centril · 2022-10-06T23:01:58Z

sway_libs/src/string/string.sw

+    /// Removes the last character from the `String` buffer and returns it.
+    pub fn pop(self) -> Option<u8> {
+        self.bytes.pop()
+    }


This and remove are problematic as well in terms of unicode.

bitzoic · 2022-10-07T14:20:06Z

Perhaps we only want to start off with the interface, but then we should state that this does no validation and essentially is just Vec<u8> (which Rust's String is also backed by, but the API is unicode-aware).

As the use for strings in blockchains is pretty minimal and with the current support for characters and str in Sway, this is definitely more of an interface than anything. I see the primary use case being to pass a string to a contract rather than building a string in the contract, for example needing to store a URI for some NFT metadata. This is something that has been asked for by developers previously.

Nonetheless, I do hope to incorporate a safer use of strings once chars are available.

… UTF-8 encoding

Centril

Looks good with the new docs 🚀

matt-user

lgtm

matt-user · 2022-10-10T15:05:06Z

sway_libs/src/string/README.md


 For more information please see the [specification](./SPECIFICATION.md).

 > **Note** There is currently no way to convert a `str` to a `String`.

+## Known Issues
+
+It is important to note that unlike Rust's `String`, this `String` library does **not** guarantee a valid UTF-8 string. The `String` currently behaves only as a `vec` and does not perform any validation. This intended to be supported in the future with the introduction of [`char`](https://github.com/FuelLabs/sway/issues/2937) to the Sway language.


Good comment, this clears up a lot of the confusion I was having with the lib

sway_libs/src/string/README.md

tests/src/test_projects/string/tests/functions/nth.rs

tests/src/test_projects/string/tests/functions/pop.rs

tests/src/test_projects/string/tests/functions/push.rs

tests/src/test_projects/string/tests/functions/remove.rs

tests/src/test_projects/string/tests/functions/with_capacity.rs

bitzoic added 7 commits August 3, 2022 11:23

Inital Commit

c1f05ee

Add base functions

1dbabcc

Refactor and Rename to match Rust

8a24ca7

Tests outline

80471e3

Update to string

2838a0d

Add len function test

de3d3bf

Add is_empty tests

4b338c7

bitzoic added New Feature New addition that does not currently exist Awaiting SDK feature(s) SDK does not support desired functionality, yet labels Aug 3, 2022

bitzoic self-assigned this Aug 3, 2022

bitzoic linked an issue Aug 3, 2022 that may be closed by this pull request

Strings Library #11

Closed

4 tasks

bitzoic added 8 commits August 4, 2022 11:50

Add clear function tests

e16aeb9

Add capacity function tests

6caec29

Add new function tests

b109dfb

Add push function tests

e3ab49c

Fix capacity test

352c997

Add with_capacity function tests

2830e6b

Add some more functions

cf8608f

First iteration of push_str

f3f195b

bitzoic added 7 commits October 4, 2022 14:52

Resolve Merge conflicts

3888a91

Remove functions with relation to str

eafb587

Update function test list to match new string methods

d7bf98d

Update empty tests

c37c295

Update len tests

0529954

Update push test

5033649

Update to use constants for numbers

b2089bf

mohammadfawaz mentioned this pull request Oct 4, 2022

Consider adding char as a primitive type FuelLabs/sway#2937

Open

bitzoic added 2 commits October 4, 2022 15:38

Add as_bytes test

83ce059

Add from_utf8 test

54406dc

bitzoic added 2 commits October 5, 2022 16:35

Merge remote-tracking branch 'origin/master' into bitzoic-11

eb02cc9

Add how to import to README

68afba3

Braqzen reviewed Oct 6, 2022

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matt-user requested changes Oct 6, 2022

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bitzoic added 4 commits October 6, 2022 15:30

Update code based on suggestions

e128a7f

Update documentation based on suggestions

d3b5006

Remove warnings and fix instance calls

0080b06

Merge remote-tracking branch 'origin/master' into bitzoic-11

33a00f7

Centril reviewed Oct 6, 2022

View reviewed changes

bitzoic added 3 commits October 7, 2022 11:42

Update wording of documentation to inform of String's usage of unsafe…

b7e61fd

… UTF-8 encoding

Update incorrect link to source README

7db8761

Refactor SDK tests into multiple files

ae7a296

Centril previously approved these changes Oct 8, 2022

View reviewed changes

Add None for nth test

89d06d6

bitzoic dismissed Centril’s stale review via 89d06d6 October 10, 2022 14:36

Add EOD to test file

c79457c

bitzoic requested review from matt-user and Braqzen October 10, 2022 14:58

matt-user previously approved these changes Oct 10, 2022

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Braqzen reviewed Oct 10, 2022

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bitzoic added 2 commits October 10, 2022 11:59

Update Documentation based on suggestions

446f6a7

Remove unneeded braces from tests

ab46610

bitzoic dismissed matt-user’s stale review via ab46610 October 10, 2022 16:00

bitzoic requested review from Braqzen and matt-user October 10, 2022 16:23

Braqzen approved these changes Oct 10, 2022

View reviewed changes

bitzoic merged commit d250e34 into master Oct 10, 2022

bitzoic deleted the bitzoic-11 branch October 10, 2022 17:08

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Strings Library #12

Strings Library #12

bitzoic commented Aug 3, 2022 •

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SwayStar123 commented Sep 28, 2022

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matt-user Oct 10, 2022


		For more information please see the [specification](./SPECIFICATION.md).

		> Note There is currently no way to convert a `str` to a `String`.

Strings Library #12

Strings Library #12

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bitzoic commented Aug 3, 2022 • edited Loading

Type of change

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Notes

Related Issues

SwayStar123 commented Sep 28, 2022

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