Important

The primary repository has moved to git.rosseaux.net/BeRo1985/pinja. This GitHub repository is kept up-to-date via push mirroring.

Pinja

Pinja is a Jinja-subset-compatible template engine for Object Pascal. It's primarily designed for usage with PasLLM for Large Language Model applications, since LLM models have often Jinja templates built-in for prompt processing. But it can be used in any Object Pascal application for other purposes as well, where a lightweight Jinja-like template engine is needed.

Features

A lot of Jinja features are supported, including:

• Expression Evaluation: Full expression support with proper operator precedence

  • Arithmetic operators: +, -, *, /, // (floor division), % (modulo), ** (power)
  • Comparison operators: ==, !=, <, <=, >, >=
  • Logical operators: and, or, not
  • Bitwise operators: &, ^, bor, <<, >>, ~
  • String concatenation: ~
  • Membership operators: in, not in
  • Identity tests: is, is not
  • Ternary expressions: value if condition else alternative

• Control Flow Structures

  • Conditional statements: {% if %}, {% elif %}, {% else %}, {% endif %}
  • For loops: {% for item in items %} with optional filter conditions
  • Loop control: {% break %}, {% continue %}
  • Filter blocks: {% filter name %}...{% endfilter %}
  • Generation blocks: {% generation %}...{% endgeneration %}

• Variable Management

  • Variable assignment: {% set name = value %}
  • Set blocks: {% set name %}...{% endset %}
  • Attribute access: object.attribute
  • Array/object indexing: array[index]
  • Slicing support: array[start:stop:step]

• Macros and Callable Functions

  • Macro definitions: {% macro name(params) %}...{% endmacro %}
  • Positional and keyword arguments
  • Call blocks: {% call macro_name(args) %}...{% endcall %}
  • Call parameters: {% call(params) macro_name(args) %}...{% endcall %}

• Comprehensive Built-in Filters (40+ filters)

  • String manipulation: upper, lower, trim, strip, capitalize, title, replace, center, truncate
  • String tests: startswith, endswith, count
  • List operations: first, last, join, sort, reverse, unique, slice, batch, random
  • Formatting: format, indent, wordcount, striptags, urlize, pprint
  • Type conversions: int, str/string, list, to_json
  • Data manipulation: default, length, dictsort, groupby
  • Escaping: escape/e, safe, xmlattr
  • Math: round

• Built-in Functions (20+ functions)

  • Type conversions: int(), float(), str(), bool(), list()
  • Math operations: abs(), min(), max(), sum(), round()
  • Sequence operations: len(), range(), keys(), values(), items()
  • Filtering: select(), reject(), selectattr(), rejectattr(), map()
  • Utilities: namespace(), joiner(), tojson(), equalto(), in(), raise_exception()

• Data Types

  • Null values
  • Booleans
  • Integers (64-bit)
  • Floating-point numbers
  • Strings (UTF-8 encoded)
  • Arrays (dynamic lists)
  • Objects (key-value dictionaries)
  • Callable objects (functions and macros)

• Safety and Escaping

  • HTML escaping for safe output
  • JSON serialization support
  • Safe filter to bypass auto-escaping

• LLM Integration

  • Compatible with Jinja2/3 chat template formats used by Large Language Models
  • Separate PinjaChatTemplate unit for LLM-specific functionality
  • Designed for prompt processing in AI applications

• Object Pascal Features

  • Compatible with Delphi ≥11.2 and FreePascal ≥3.3.1
  • No external dependencies except PasJSON and PasDblStrUtils
  • Cross-platform support (32-bit and 64-bit)
  • zlib license for flexible usage

Missing features compared to full Jinja2:

• No support for asynchronous templates
• Limited support for custom filters and tests
• Some advanced features like template inheritance are not fully implemented
• Inclusion of external templates is not supported
• And some more... but for LLM prompt processing, this is usually sufficient and already more than needed.

License

It's licensed under the zlib license. See the source code headers for details.