promplate-inspect

Inspect input variables used in a promplate template.

Useful when instructing an LLM to produce structural data with certain fields, or for you to quickly understand the data structure a template expects.

pip install promplate-inspect

Usage

from promplate import Template
from promplate_inspect import find_input_variables_in_template

t = Template("""

    {#
        import a as b
        from c import d
    #}

    {{ e }}

    {{ f.strip() }}

    {{ list }}

    {#
        g += 1
        h = { **h }
    #}

    {% for i in func() %}

        {{ [ j for j in range(i) ] }}

    {% endfor %}

""")

find_input_variables_in_template(t)  # {'e', 'f', 'g', 'h'}

Note that it excludes builtin names by default. If you allow LLM to output variables like dict or list, you can specify the second parameter exclude_builtins:

find_input_variables_in_template(t, exclude_builtins=False)  # {'e', 'f', 'g', 'h', 'list'}

As you see, variables that defined explicitly in the templates are not filtered out as expected. And functions above like func and range are always excluded because LLM can never out callable instances typically.

Limitations

1. This parser is still work in progress. If you includes any of these code in your {{ }}/{# #} tags, the result may be wrong:
   • Parameters of function. Inspecting {{ (lambda x: x + 1)(y) }} should output {'y'} but outputs {'x', 'y'} for now.
   • Similarly, variables defined in with statements and except statements are not excluded for now.
2. This implementation use ast to parse the template. It never run the code, so these monkey patches won't be tracked:
   • Getting variables from globals()/locals()/__main__ won't be finded. Such as name won't be found in {{ locals()["name"] }}.
   • Assigning values to globals()/locals()/__main__ won't be excluded. Even if you wrote {# globals().setdefault("name", "value") #}, name will still be found in {{ name }}.
3. For now it only find variables in the given template itself. It don't find variables needed in the components used by it.