text.template- Simple template expander
This module lifts Gauche’s built-in string interpolation feature to be more general template engine.
Gauche’s string interpolation syntax is expanded at read time and then handled by macro expanders, and becomes a simple Scheme code fragment. For example, if you have this:
(let ([x 10]) #"The square of x is ~(* x x).")
It is eventually converted to this after macro expansion:
(let ([x 10]) (string-append '"The square of x is " (x->string (* x.0 x.0)) '"."))
It is a kind of template expansion, but you have to have the template string as a literal, so it’s restricted. With this module, you can feed template string and the bindings of the value at the runtime:
(define *template* "The square of x is ~(* x x).") (expand-template-string *template* (make-template-environment :bindings '(x 10))) ⇒ "The square of x is 100."
The syntax of template strings is the same as string interpolation
(see String interpolation); that is, tokens following
is read as a Scheme expression. In case if the token is a symbol
and you need to delimit it from subsequent characters, you can use
symbol escape by
You also need to provide a template environment, where the expressions in the template is evaluated. Note that, unlike string interpolation, those expressions can’t refer to the local bindings.
Expands a template string template with a template environment env, and returns the result string.
Reads a template string from a file named by filename, expands it with a template environment env, and returns the result string.
If filename is not an absolute path, it is looked in the directories listed in paths.
Creates and returns a template environment. A template environment is like a module (see Modules): It maps symbols to values, and it can import bindings from other modules, or extend other modules.
The keyword arguments extends and imports must be a list of symbols; they specify names of modules to inherit from or to import from.
The keyword arguments bindings must either be a dictionary
(anything that inherits
<dictionary>), or a key-value list.
The mappings represented by it are incorporated to the environment.