CascadiaJS 2013 is proudly brought to you by

You can view the rest of the videos on our2013 playlist on Youtube

My Little Parser: Tooling is Magic

• Name : Chris Dickinson
• Twitter : @isntitvacant
• Github : chrisdickinson
• Website : neversaw.us

Abstract

Code is abstraction. When we code, we punch keys to write tokens to form expressions to build great towering syntactical forests. When we code, we weave a flow of data from outset to outcome. When we code, we alter the course of electrons, inadvertantly hastening the heat death of the universe by just that little bit.

We edit code at that one level of abstraction -- keypresses, text -- and we treat with code -- searching, replacing, grep'ing -- at that level. What problems can we free ourselves from by interacting with our code at the AST level?

One of JavaScript's many sterling qualities is its relatively simple, unambiguous syntax. Another is its community's familiarity with querying and manipulating complex, nested tree structures. With AST-aware tools, we can free ourselves from the opportunity cost of switching our module loader, frontend framework, or test framework. What other new tools can we create?

In this talk, I will touch on:

• The basics of ASTs and streaming parsers.
• CSS as a general purpose AST selector language.
• Building unix-style small, composable command line tools (and node.js modules) to search and edit JavaScript ASTs.
• Using AST transformation to switch module loaders, test frameworks, and APIs.
• Using CSS-the-AST-selector to search for unsafe operations in existing codebases, intelligently grep for code, and build simple, flexible linters for common programmer errors.

Speaker Bio

I'm a JavaScript developer at Urban Airship in sunny Portland, OR. The occasionally odd physics in voxel.js are my fault. I'm also to blame for at least one reimplementation of inflate in JavaScript, to further the evil goal of getting git to run in pure js.