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util.nix/package/c/hectic/docs/templater.md
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Templater Configuration Documentation

The templating engine supports flexible customization of tag syntax parameters. Each parameter can be overridden in the configuration file. Below are the main groups of parameters with usage examples and configuration notes.

Legend


General Parameters

  • Open Brace
    A non-empty string marking the beginning of a tag.
    Example: {{

  • Close Brace
    A non-empty string marking the end of a tag.
    Example: }}


Section Tags

Parameters defining syntax for blocks controlling loops or nested structures.

  • Prefix
    Marks the start of a section (e.g., loops).
    Example: for | (Empty)

  • Suffix
    Delimiter between variables and collections.
    Example: in | #

  • Post-Suffix
    Finalizes the section block.
    Example: end | /

Example

Section Example:

{{ for item in items }}
  {{ item.name }}
  some text
  {{ for inner_item in item.inner_items join '\n' }}
    <p>some other text</p>
    {{ inner_item }}
  {{ end }}
  \n
{{ end }}

Context Example:

{
  "items": [
    {
      "name": "some name",
      "inner_items": ["value1", "value2"]
    }
  ]
}

Interpolation Tags

Inserts variable values or expression results directly into templates.

  • Prefix
    Indicates an interpolation operation.
    Example: $ | (Empty)

Interpolation Example:

  {{ interpolation_field }}

Context Example:

{ 
    "interpolation_field": "some value",
    "interpolation_field_null": null
}

Include Tags

Includes content from other templates.

  • Prefix
    Marks the tag as an inclusion operation.
    Example: include | + | <

Include Example:

  text before
  {{ include inner_template }}
  <div id="footer">...</div>

Context Examples:

// Separate context
{
  "include": {
  "inner_template": {
      "template": "{{ field }}",
      "context": { "field": "value" }
    }
  }
}

// Shared root context
{
  "field": "value",
  "include": {
    "inner_template": {
      "template": "{{ field }}"
    }
  }
}

// Plain text inclusion
{
  "field": "value",
  "include": {
    "inner_template": {
      "content": "<p>value</p>"
    }
  }
}

Execution Tags

Note: implemented as a wrapper on applicable platforms, in that case must evel Postgresql functions. Enables calling functions with arguments, or execute code. Have hardcoded context var - alows use template context

  • Prefix
    Denotes a function call.
    Example: exec | (Empty)

Function Example:

  {{ exec RETURN my_function(context->arg1, context->arg2, 'literal') }}
  {{ exec RETURN 'aaaaa' }}

Notes

  • Unique Tags: Open Brace, Close Brace, and Null Handler must be distinct.
  • Nested Constructs: Supported.
  • Unclosed Tags: Must return an error.
  • Missing Fields/Functions/Templates: Configurable to either return an error or warning.
  • Circular Includes: Detect when possible.
  • No Shadowing: Variables defined in section tags must not conflict with context variable names, otherwise, return an error.

Shared example

  <div>text before<div>

  {{ include inner_template }}

  {{ name }}

  {{ for item in array }}
    some text: {{ name2 }}
    {{ item.name }}
  {{ end }}

  <div>code insertion:</div>
  {{ execute
    context + '{"name3": "zalupa"}';

    IF context->condition THEN
      RAISE INFO 'some log';

      RETURN 'some text';
    END
    RETURN 'some other text';
  }}

  <div id="footer">...</div>