"One [problem] is that the user has no easy way of discovering how complex the recurrence rules can be."
Easy. Show both the text field and the traditional UI at the same time right from the beginning and link them together so that manipulating the traditional UI updates the text field and vice-versa. Have an area where you show a few additional alternate syntaxes for the same "sentence" so that users can see that the syntax is far from being rigid, however if you input a sentence and then later manipulate the UI, the text field should retain the original style (not canonicalize to the default syntax).
Ok, this might not be so easy to implement but I'm pretty sure it's the best solution for the user as it scales from beginner to expert.
Tripeedo (http://www.tripeedo.com) actually does this - I agree, it's a really nice way to let the user know they're ding the right thing. I find it a lot better than the traditional calendar widgets.
On the other hand, there are a lot of people out there who don't like the keyboard. It's easy to forget this, especially with so many people in CS and IT who try to never take their hands away from it , but there are a lot of potential users who would rather do everything with the mouse. Efficiency isn't a concern for these people (like my mom), since the input speed into the computer isn't ever their bottleneck, no matter how slow.
That said, nice job! I love natural language parsers!
Yeah, this is actually an issue we've encountered with Tripeedo.
As a UI element, the calendar widget seems clunky and outdated -- yet if you don't know the exact date of your travel, it's nice to have a visual prompt. So there are cases where text input alone might not be sufficient. The user might need or want more guidance.
It's a challenging task to try to integrate both input mechanisms at the same time. We're exploring it though.
That's not "less UI", it's just a different UI with fewer graphical elements.
I'm not arguing against it-- he's come up with a simple DSL, and exposed that to the users-- but what would it mean to have "less UI" and maintain a given feature-set?
How is it not less UI, if he reduced multiple screens and buttons to one text box? He literally reduced the quantity of interfaces a user interacts with.
I'm not convinced that we can treat "less UI = better app" as an axiom but I don't see your point.
Less UI in your sense can indeed lead to user friendlyness. One example: I use a plain textfile as my PIM. Why? Because data viewer and editor are the same. Not even a mouseclick away.
Easy. Show both the text field and the traditional UI at the same time right from the beginning and link them together so that manipulating the traditional UI updates the text field and vice-versa. Have an area where you show a few additional alternate syntaxes for the same "sentence" so that users can see that the syntax is far from being rigid, however if you input a sentence and then later manipulate the UI, the text field should retain the original style (not canonicalize to the default syntax).
Ok, this might not be so easy to implement but I'm pretty sure it's the best solution for the user as it scales from beginner to expert.