alda-cljs

An experimental ClojureScript port of Alda.

Development

• Have Boot installed.

• Run boot dev.

  This will watch for changes to source files and whenever there is a change, re-render the ClojureScript files to target/main.js.

• Open target/test.html in your browser and open the JavaScript console. This file just loads target/main.js -- it's useful as a sandbox for testing the JavaScript code that this library generates.

  The boot dev task has a built-in browser reload websocket. Any time a change is made, your browser window will refresh automatically so that you can see the changes right away.

Demo

There are a couple things you can do so far:

• Parse a demo score -- uncomment the 3 commented lines in alda-cljs.core and you will see the parse tree printed out to the console.

• Parse arbitrary Alda code using the exported alda-cljs.parser/parse function:

    // just return an array representing the parse tree
    alda_cljs.parser.parse('piano: c');
  
    // also print the ClojureScript representation to the console
    alda_cljs.parser.parse('piano: c', {print: true});
  

At the moment, the parse trees you see are the raw result of parsing code using the Alda grammar.

What Alda (the Clojure project) does:

• Use the Alda grammar to generate a parse tree.
• Transform that parse tree into executable Clojure code. (Generating code and evaluating it is a common task in Lisp, where code is data.)
• Define a namespace (alda.lisp) full of functions that provide a context for what happens when you evaluate the code. In the alda.lisp namespace, there are functions called score, note, chord, octave, etc.
• Eval the generated Clojure code to build the internal representation of the score.

What alda-cljs will do:

• Use the Alda grammar to generate a parse tree.
• Transform that parse tree into ... ?
• ????
• PROFIT

ClojureScript doesn't have eval (yet?) so this is going to be a little more complicated. We may need to transform the parse tree into a kind of pseudo-Lisp language (it practically already is one), along with a basic Lisp interpreter that manually traverses the Lisp "program," evaluating things conditionally, i.e. "if the first item in the array is :score, then run this score function," etc.

License

Copyright © 2015 Dave Yarwood et al

Distributed under the Eclipse Public License version 1.0.