It’s just two functions, really. And a class if you want it!

pip install prompt_builder

The simplest way to use this is just to use the two functions, fields_needed and substitute_vals. This introduces no new types, since you just use a plain Python format string as your raw template.

The function fields_needed tells you which fields need to be filled to complete the template:

s = " Hello {name}, your friend is {friend}"
print(s)

 Hello {name}, your friend is {friend}

fields_needed(s)

{'friend', 'name'}

The function substitute_vals lets you fill some or all of the fields, in any order, and returns a new template:

s2 = substitute_vals(s, name="Bob")
print(s2)

 Hello Bob, your friend is {friend}

s3 = substitute_vals(s,friend="Jack")
print(s3)

 Hello {name}, your friend is Jack

Of course, by using kwargs syntax, you can use a dictionary or a dataclass to provide field values as well:

val_set1 = {"name":"Alexis", "friend":"Claude"}
s4 = substitute_vals(s,**val_set1)
print(s4)

 Hello Alexis, your friend is Claude