NAME

Config::BINDish::Expandable - Config::BINDish extension implmeneting expandable strings

DESCRIPTION

This module extends Config::BINDish with strings which can include other option values. Only double-quoted string (i.e. those for which Config::BINDish::Grammar::Value and Config::BINDish::AST::Value have type name set to dq-string) are expandable.

To incorporate a value into a string the following macro format is used:

'{' <option> | <option-path> '}'

option is a plain string naming an option from the current block:

server "S1" {
        name "server.local";
        description "{name} is a mock server"; # becomes "server.local is a mock server"
    }

option-path defines a path to the option if it is located in another block. The path can be relative or absolute.

The absolute path is started with a slash:

base-url "https://localhost"
    resource "Test" {
        url "{/base-url}/test";
    }

To define a block where the option is to be located the following syntax is used:

block-type[([name [, class]])]

For example:

resource "default" {
        url "https://localhost";
    }
    resource "test1" addr {
        component "foo"
    }
    client-data {
        url "{/resource(default).url}/{/resource("test1", addr).component}"; # https://localhost/foo
    }

Nested blocks are joined with a dot:

resource "default" {
        urls {
            base "https://localhost";
        }
    }
    client-data {
        user-profile "{/resource(default).urls.base}/user"; # https://localhost/user
    }

Symbol escaping is traditionally done with a backslash:

client-data {
        description "Some basic info \{?} \\";
    }

This Is A Value!

Because expandable strings are normal values they can be used anywhere, where a value is accepted we can do things like expanding a string within a macro:

default-server "A1";
    server "A1" {
        url "https://a1.local";
    }
    server "A2" {
        url "https://a2.local";
    }
    network "Office" {
        api-url "{/server("{/default-server}")}/api"; # https://a1.local/api
    }

This works because when a macro is expanded server name and class can be specified using string values.

SEE ALSO

Config::BINDish, Config::BINDish::AST

AUTHOR

Vadim Belman <[email protected]>