https://github.com/naqvis/crystal-xpath2
XPath implemenation in Pure Crystal
https://github.com/naqvis/crystal-xpath2
crystal crystal-lang crystal-language crystal-shard xpath xpath-api xpath2
Last synced: 6 months ago
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XPath implemenation in Pure Crystal
- Host: GitHub
- URL: https://github.com/naqvis/crystal-xpath2
- Owner: naqvis
- License: mit
- Created: 2020-05-01T17:08:33.000Z (almost 6 years ago)
- Default Branch: master
- Last Pushed: 2021-04-04T16:32:39.000Z (almost 5 years ago)
- Last Synced: 2025-05-12T22:55:06.052Z (11 months ago)
- Topics: crystal, crystal-lang, crystal-language, crystal-shard, xpath, xpath-api, xpath2
- Language: Crystal
- Homepage:
- Size: 41 KB
- Stars: 11
- Watchers: 4
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# Crystal XPath2
[](https://github.com/naqvis/crystal-xpath2/releases)
[](https://naqvis.github.io/crystal-xpath2/)
**Crystal XPath2** Shard provide XPath implementation in **Pure Crystal**. Performs the compilation of XPath expression and provides mechanism to select/evaluate nodes from HTML or other documents using XPath expression
Supported Features
===
#### The basic XPath patterns.
> The basic XPath patterns cover 90% of the cases that most stylesheets will need.
- `node` : Selects all child elements with node Name of node.
- `*` : Selects all child elements.
- `@attr` : Selects the attribute attr.
- `@*` : Selects all attributes.
- `node()` : Matches an org.w3c.dom.Node.
- `text()` : Matches a org.w3c.dom.Text node.
- `comment()` : Matches a comment.
- `.` : Selects the current node.
- `..` : Selects the parent of current node.
- `/` : Selects the document node.
- `a[expr]` : Select only those nodes matching a which also satisfy the expression expr.
- `a[n]` : Selects the nth matching node matching a When a filter's expression is a number, XPath selects based on position.
- `a/b` : For each node matching a, add the nodes matching b to the result.
- `a//b` : For each node matching a, add the descendant nodes matching b to the result.
- `//b` : Returns elements in the entire document matching b.
- `a|b` : All nodes matching a or b, union operation(not boolean or).
- `(a, b, c)` : Evaluates each of its operands and concatenates the resulting sequences, in order, into a single result sequence
#### Node Axes
- `child::*` : The child axis selects children of the current node.
- `descendant::*` : The descendant axis selects descendants of the current node. It is equivalent to `"//"`.
- `descendant-or-self::*` : Selects descendants including the current node.
- `attribute::*` : Selects attributes of the current element. It is equivalent to `@*`
- `following-sibling::*` : Selects nodes after the current node.
- `preceding-sibling::*` : Selects nodes before the current node.
- `following::*` : Selects the first matching node following in document order, excluding descendants.
- `preceding::*` : Selects the first matching node preceding in document order, excluding ancestors.
- `parent::*` : Selects the parent if it matches. The `".."` pattern from the core is equivalent to 'parent::node()'.
- `ancestor::*` : Selects matching ancestors.
- `ancestor-or-self::*` : Selects ancestors including the current node.
- `self::*` : Selects the current node. `'.'` is equivalent to `"self::node()"`.
#### Expressions
Shard supports three types: number, boolean, string.
- `path` : Selects nodes based on the path.
- `a = b` : Standard comparisons.
* a `=` b `true` if a equals b.
* a `!=` b `true` if a is not equal to b.
* a `<` b `true` if a is less than b.
* a `<=` b `true` if a is less than or equal to b.
* a `>` b `true` if a is greater than b.
* a `>=` b `true` if a is greater than or equal to b.
- `a + b` : Arithmetic expressions.
* `- a` Unary minus
* a `+` b Add
* a `-` b Substract
* a `*` b Multiply
* a `div` b Divide
* a `mod` b Floating point mod, like Java.
- `a or b` : Boolean `or` operation.
- `a and b` : Boolean `and` operation.
- `(expr)` : Parenthesized expressions.
- `fun(arg1, ..., argn)` : Function calls:
| Function | Supported |
| --- | --- |
`boolean()`| ✓ |
`ceiling()`| ✓ |
`choose()`| ✗ |
`concat()`| ✓ |
`contains()`| ✓ |
`count()`| ✓ |
`current()`| ✗ |
`document()`| ✗ |
`element-available()`| ✗ |
`ends-with()`| ✓ |
`false()`| ✓ |
`floor()`| ✓ |
`format-number()`| ✗ |
`function-available()`| ✗ |
`generate-id()`| ✗ |
`id()`| ✗ |
`key()`| ✗ |
`lang()`| ✗ |
`last()`| ✓ |
`local-name()`| ✓ |
`name()`| ✓ |
`namespace-uri()`| ✓ |
`normalize-space()`| ✓ |
`not()`| ✓ |
`number()`| ✓ |
`position()`| ✓ |
`replace()`| ✓ |
`reverse()`| ✓ |
`round()`| ✓ |
`starts-with()`| ✓ |
`string()`| ✓ |
`string-length()`| ✓ |
`substring()`| ✓ |
`substring-after()`| ✓ |
`substring-before()`| ✓ |
`sum()`| ✓ |
`system-property()`| ✗ |
`translate()`| ✓ |
`true()`| ✓ |
`unparsed-entity-url()` | ✗ |
## Installation
1. Add the dependency to your `shard.yml`:
```yaml
dependencies:
xpath2:
github: naqvis/crystal-xpath2
```
2. Run `shards install`
## Usage
refer to `spec` for usage examples or refer to [Crystal HTML5](https://github.com/naqvis/crystal-html5) and [JSON XPath](https://github.com/naqvis/json-xpath) for implementation details.
## Development
To run all tests:
```
crystal spec
```
## Contributing
1. Fork it ()
2. Create your feature branch (`git checkout -b my-new-feature`)
3. Commit your changes (`git commit -am 'Add some feature'`)
4. Push to the branch (`git push origin my-new-feature`)
5. Create a new Pull Request
## Contributors
- [Ali Naqvi](https://github.com/naqvis) - creator and maintainer