tengri/dsl

dizzle is a means of adding a tiny interpreted domain-specific language to your programs.

dizzle currently provides an s-expression based syntax.

dizzle parses source code by means of the Dsl, DslExpr and DslWord traits. those are implemented for basic stringy types and their Option and Result wrapped analogs. to customize parsing, define and use your own traits on top of the provided ones.

dizzle evaluates the parsed source code by means of the DslNs trait. the methods of this trait match literals, words, and expressions, against pre-defined lists. the dsl_words and dsl_exprs macros let you define those lists slightly less verbosely.

goals

• const parse
• live reload
• serialize modified code back to original indentation

examples

in tengri_output

(bsp/s (fixed/y 2 :toolbar)
  (fill/x (align/c (bsp/w :pool
    (bsp/s :outputs (bsp/s :inputs (bsp/s :tracks :scenes)))))))

in tengri_input

(@u       undo 1)
(@shift-u redo 1)
(@e       editor show :pool-clip)
(@ctrl-a  scene add)
(@ctrl-t  track add)
(@tab     pool toggle)

implementation notes

DslExpr trait behavior

this is the trait which differentiates "a thing" from "a thing that is many things".

source	key	exp	head	tail
a	a	e0	a	None
(a)	e1	a	(a)	None
a b c	e2	e0	a	b c
(a b c)	e1	a b c	(a b c)
(a b c) d e	e1	e3	(a b c)	d e
a (b c d) e f	e1	e0	a	(b c d) e f

• e0: Unexpected 'a'
• e1: Unexpected '('
• e2: Unexpected 'b'
• e3: Unexpected 'd'

possible design for operator-based syntax

• replace: (:= :name :value1 :valueN)
• append: (:+ :name :value2 :valueN)
• filter: (:- :name :value2 :valueN)
• map: (:* :name op)
• reduce: (:/ :name op)