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Welcome to the wiki.

For now this page keeps track of known issues and ideas for improvement.

Known issues

• Mobile compatibility
  • Code editor is broken on mobile https://github.com/ajaxorg/ace/issues/37
    Idea: could switch to https://codemirror.net/, depending on usage stats.
  • Modal dialogs may not scroll on iOS. Possibly related to https://github.com/twbs/bootstrap/issues/14839 ?
• Framerate drops when state nodes exceed a certain amount.
  • Likely caused by lack of optimization / GPU acceleration in SVG: http://www.crmarsh.com/svg-performance/.
  • Notes: profiler blamed getBBox() for causing relayout, but removing it did nothing. Could try the CSS transform trick, or switch from SVG to Canvas.
• Parser doesn't catch duplicated symbols when using multi-symbol matching; e.g. start: {1: R, [1,0]: L} should detect the duplicated 1 keys. Will fix.
• Internet Explorer
  • SVG marker-ends (arrowheads) are left behind when their paths move
    Workaround: click "Load machine" to recreate the paths.
  • data URIs aren't supported in anchor elements
    Could add IE-only downloading logic, depending on usage stats.
• Firefox doesn't support SVG letter-spacing https://bugzilla.mozilla.org/show_bug.cgi?id=371787

Want to add

Straightforward

• Auto-arrange self-loops to avoid edge overlap
• Export formats: SVG, PNG, Graphviz, TikZ automata
• Document list reordering, bulk editing
• Auto-detect DFAs and simplify edge labels: 0 → R to 0 and 1 → R to 1.
• Step counter, possibly jump to step

Needs design

• 2D history trace graphing the tape over time.
  • Concerns:
    • Placement relative to the state diagram and code editor. Ideally you'd be able to see both the diagram and the trace as you edit.
    • Coordination with simulator: head-centered simulator vs. tape-centered trace. What happens when tape head goes out of bounds — display trace page by page?
• Faster speed options
  • Concerns:
    • Interface: whole-app option, per-machine, or both?
    • Measure: relative, or based on real time (e.g. avg. 3 steps/s)?
  • Alternative design: designate loops/components to skip, e.g. move-right loop, adder subroutine.
  • Unlocks: more complex examples, e.g. universal Turing machine
• Breakpoints
• Rectangular selection to move multiple nodes at once
• Start arrow
  • Concerns: arrows currently go from one state to another state (same start and end = loop). Manual adjustment of length and angle could be done via an invisible state (unintuitive), or dragging of the arrow itself (unlike other arrows).
    Preferred: estimate length based on other edges, and angle similar to auto-arranged loops.
• Double circle for halting states (no exiting transitions)
  • Will need to redo current state highlight

More ideas

• On-demand script loading
• Trash instead of delete confirmation http://alistapart.com/article/neveruseawarning
• Atomic transactions, storage error reporting
  • Concerns: Web SQL is not a standard, IndexedDB silently aborts transactions on page close
• Continuous integration, GUI testing
• Adjustable node size, aspect ratio?
• Show documents as a grid with thumbnails
  • Need a way to render the thumbnails and cache them somewhere besides local storage.
• Cloud integration?
  • Google docs, Dropbox
  • Import/export, or direct saving?