interpolate

An Erlang library to interpolate strings.

Usage

Use the interpolate:string/1 function or add the header -include_lib("interpolate/include/interpolate.hrl"). to your module and the ?f macro will be available to format your string.

Example

In an Erlang module:

module(math).

-export([sum/2]).

-include_lib("interpolate/include/interpolate.hrl").

sum(X, Y) ->
    ?f("The sum of ~p[X] and ~p[Y] is ~p[X+Y]").

The result of the function will be a UTF-8 binary:

1> math:sum(1,2).
<<"The sum of 1 and 2 is 3">>

How it works

This lib uses a parse_transform to expand the string to the io_lib:format/2 function. The string should be written thinking in the io_lib:format/2 syntax, but the arguments of the control sequences must be written next to them inside closed brackets, as a list. All control sequences are auto-prefixed with the modifier t (Unicode translator) For example:

Foo = "😊",
<<"😊"/utf8>> = ?f("~s[Foo]").

The ?f("~s[Foo]") is compiled to interpolate:string("~s[Foo]") and expanded to

iolist_to_binary(io_lib:format(<<"~ts"/utf8>>, [Foo])).

See more examples in the interpolate_test.erl under the test folder.