62 lines
2.3 KiB
Markdown
62 lines
2.3 KiB
Markdown
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# glemplate
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[](https://hex.pm/packages/glemplate)
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[](https://hexdocs.pm/glemplate/)
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Glemplate is a simplistic template engine for Gleam. The aim was to learn how to make such a thing
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and fill simple use cases. At this stage, it can be used for simple plain text and HTML templates,
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and for other contexts by supplying a custom encoding function.
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## Quick start
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```gleam
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import gleam/map
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import glemplate/parser
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import glemplate/html
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import glemplate/assigns
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let template = "<b>Welcome, <%= name %>!</b>"
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assert Ok(tpl) = parser.parse_to_template(template, "input.html.glemp")
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let assigns = assigns.from_list([#("name", assigns.String("<Nicd>"))])
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let template_cache = map.new()
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html.render(tpl, assigns, template_cache) // "<b>Welcome, <Nicd>!</b>"
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```
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The main modules:
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- [glemplate/parser](glemplate/parser.html): The parser implements and documents the string
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template syntax.
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- [glemplate/ast](glemplate/ast.html): The abstract syntax tree (AST) is the data format of the
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parsed templates.
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- [glemplate/renderer](glemplate/renderer.html): The renderer takes in the parsed AST, input data,
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and a cache of templates, and renders the template into an output string builder.
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- [glemplate/html](glemplate/html.html) and [glemplate/text](glemplate/text.html) have helper
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functions for rendering HTML and plain text templates.
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Using templates with Glemplate has two main things to deal with:
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1. parsing templates into AST with the parser, and
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2. rendering that AST into some output with assigns (input data).
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Since Gleam has no metaprogramming, the parsing of templates needs to be done at startup time (or
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whenever deemed necessary when templates have changed). The resulting AST should be stored for
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later use in e.g. ETS, process state, persistent_term…
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## Limitations
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- Static values in templates in place of variables aren't supported.
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- It's possible to create infinite loops with child templates, it's not recommended to give access
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to writing templates to untrusted users.
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- Calling functions from templates is not supported.
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## Installation
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This package can be added to your Gleam project:
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```sh
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gleam add glemplate
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```
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and its documentation can be found at <https://hexdocs.pm/glemplate>.
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