MODEST-CONFIG is a simple configuration file parser for Common Lisp. Config files contain a single Common Lisp property list, and the parser provides a convenient way to extract the properties.

Quickstart

Given a config file:

(
  ;; This sets property FOO
  foo :some-value

  ;; Here is another property
  bar "This is a string"

  zot (list 1 2 3 4 5)

  ;; Config may also contain functions
  ;; ... if you are willing to trust your config maintainer
  quux (lambda (wombat)
         (format nil "Hello, ~a" wombat))
)

When you load and extract properties like this:

(with-config "example.config" (zot bar quux)
  (format t "The value of zot is ~s~%" zot)
  (format t "~a says bar~%" bar)
  (format t "(quux \"World\") => ~s~%" (funcall (eval quux) "World")))

Then you get this output:

The value of zot is (1 2 3 4 5)
This is a string says bar
(quux "World") => "Hello, World"

Loading modest-config

(ql:quickload :modest-config)

The system only contain the package modest-config, which also has the nickname modest. There are no external dependencies.

API

find-config &optional identifier => pathname

load-config &optional identifier => plist

with-config identifier bindings &body body => result, plist

Arguments and values:

identifier -- an object used to identify what config source to use. May be pathname, string, symbol, plist, stream, or nil (details further down).

pathname -- the path to a config file.

plist -- a property list containing the configuration.

bindings -- a list of symbols that will be bound to values from configuration.

body -- forms that will be evaluated in a progn.

result -- the result of evaluating the last expression of body

Note that with-config also returns the entire configuration property list as it's second value.

Locating the config file

Configuration will be loaded based on the following rules:

Identifier type	What will happen?
pathname	File designated by pathname is assumed to contain configuration.
string	Will be turned into a pathname and handled as such.
symbol	If identifier is 'foobar or :foobar modest-config will look for a file called foobar.config, first in the current directory and secondly in the current users home directory.
list	Is assumed to be a property list containing the actual configuration. This will fail if passed to find-config.
stream	Config will be read from stream. This will fail if passed to find-config.
null	If the identifier is nil these three locations will be tried is sequence: 1) Package.config in the current directory, where package is the name of the current package. 2) modest.config in the current directory. 3) package.config in the home directory of the current user.

All functions may invoke an error condition if a configuration file can't be located.

License

Copyright 2017 Torbjørn Marø

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.