shiftless-mode

An Emacs major mode for editing shiftless configuration files and a loader & dumper.

Major Mode

(require 'shiftless-mode)

You have your font-lock (colors), you have your indentation, and you have your interface to insert structures:

Shortcut	Action
C-c l	insert a list
C-c a	insert an association
C-u ...	insert list or association without surrounding brackets
C-u C-u ...	insert list or association without any newlines

Value: prompts automatically escape strings, so no need to surround strings with single quotes or type any more backslashes than you actually want.

Value: prompts also accept a or l to insert a nested list or association

You can customize shiftless:indent-level (default 2 spaces).

Loader and Dumper

(require 'shiftless)

Access

sample.slc:

anime = [
  title = 'JoJo\'s Bizarre Adventure'
  mangaka = [
    first-name = 'Hirohiko'
    last-name = 'Araki'
    age = immortal]
  parts = ['Phantom Blood' 'Stardust Crusaders' 'Diamond is Unbreakable' 'Golden Wind']
  rating = 11/10
  episodes = 152
  [manga chapters] = [917]]

shiftless:load can take a file name or a string containing shiftless.

(let ((data (shiftless:load "sample.slc")))
  ;; implicit type access
  (shiftless:access-value data 'anime 'mangaka 'age) ;importal
  (shiftless:access-value data 'anime 'manga 'chapters) ;917
  ;; explicit type access
  (shiftless:access-as 'string data 'anime 'mangaka 'age) ;"importal"
  (shiftless:access-as 'symbol data 'anime 'mangaka 'last-name) ;araki
  )

You can also use shiftless:presentp with the same arguments as shiftless:access-value to see if the data includes a certain property.

Schema

If you want data structures eagerly loaded instead of delaying parsing until access, you can use a schema as the second argument to shiftless:load. There is the built in schema, :implicit, which loads things based on their written type (‘string’ is a string, -124.4 is a float, symbol is a symbol, t is true). Otherwise, you can give a file name of a schema file which is formatted the way you want your configuration formatted except instead of values, you have symbols that represent types: integer, float, symbol, string, boolean, or a list containing a type or other structure ([float] means list of floats).

db-info.slc

versions = [
  my = 4.2.2
  postgres = 5.30
  ms = 3.4.1]
active = postgres

schema.slc

versions = [
  my = string
  postgres = string
  ms = string]
active = string

It is not suggested to use shiftless:access-value while using a schema because the type has already been calculated.

(let ((data (shiftless:load "db-info.slc"
                            "schema.slc")))
  ;; access data
  (shiftless:access data 'versions 'postgres) ; "5.30"
  (shiftless:access data 'active)             ; "postgres"
  )

Dumping

shiftless:dump takes a lisp data structure and a file name. It writes the equivalent shiftless data structure to the file.

shiftless:stringify takes a lisp data structure and outputs the equivalent shiftless data structure as a string.

Both also take arguments to customize newlines and indent level.