9a8bbf4114
* Add AST * add make-shift testing parser, and make stuff ocmpile * add proper expression parser * make string format use ' * Add empty doc page for expressions * add tests * Clean up file structure and add unary operators * Write documentation
33 lines
926 B
Markdown
33 lines
926 B
Markdown
+++
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title = "Eww expressions"
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slug = "Embedded eww expression language"
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weight = 6
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# The embedded Eww expression-language
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Within variable references, you can make use of a small, built-in expression language.
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This can be used whereever you can use variable-references (`{{varname}}`).
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## Example
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```xml
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<button
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class="{{if button_active then 'active' else 'inactive'}}"
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onclick="toggle_thing">
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{{if button_active then 'disable' else 'enable'}}
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</button>
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Some math: {{12 + 2 * 10}}
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```
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## Syntax
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The expression language supports:
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- simple mathematical operations (`+`, `-`, `*`, `/`, `%`)
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- comparisons (`==`, `!=`, `>`, `<`)
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- boolean operations (`||`, `&&`, `!`)
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- conditionals (`if condition then 'value' else 'other value'`)
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- numbers, strings, booleans and variable references (`12`, `'hi'`, `true`, `some_variable`)
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- strings can contain other expressions again: `'foo {{some_variable}} bar'`
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