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Wherein Javascript borrows a language feature from Arc

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Re: Wherein Javascript borrows a language feature from Arc

#11

Post by tlrobinson »

ubernostrum wrote: post #10
tlrobinson wrote: post #2

You should probably assign an object to the underscore, otherwise any argument which is undefined will match: js> var _ js> _ == undefined true Just doing "var _ = {}" should be sufficient. edit: however, this conflicts with Underscore.js ( http://documentcloud.github.com/underscore/ ), but if you put an "if (typeof _ === "undefined")" around the assignment you should be ok

It also conflicts with gettext libraries. The name '_' should be considered reserved for that purpose.

True, but as long as _ is defined as a non-primitive type (namely an object or function) it can be used for both gettext (or underscore.js) and this currying function. All that's required for the currying is that comparison with anything other than itself is false.

Re: Wherein Javascript borrows a language feature from Arc

#12

Post by adamc »

ubernostrum wrote: post #10
tlrobinson wrote: post #2

You should probably assign an object to the underscore, otherwise any argument which is undefined will match: js> var _ js> _ == undefined true Just doing "var _ = {}" should be sufficient. edit: however, this conflicts with Underscore.js ( http://documentcloud.github.com/underscore/ ), but if you put an "if (typeof _ === "undefined")" around the assignment you should be ok

It also conflicts with gettext libraries. The name '_' should be considered reserved for that purpose.

Not to be a jerk, but why? What if gettext isn't important to your current application? (I don't know a lot about gettext; I went and read the blurb.)

Re: Wherein Javascript borrows a language feature from Arc

#13

Post by cwp »

ynniv wrote: post #8
WilliamLP wrote: post #3

> geolocator.getLatLng("Forest Park, St. Louis, MO", function(center) { > displayMapAt(center, 14); > }); To my eyes, that solution is just fine. I don't think I'll ever be swayed to believe that adding on layers of indirection to JavaScript code for the sake of "syntactic goodness" is rationally motivated by leading to more practical power for actually solving problems.

Agreed. If you're writing something in a web browser, use sane JavaScript. Every time I have done something "fancy" with a language, there has been a large hidden cost later on, be that complicated debugging sessions, new hire training, or unintended side effects. Terrible syntax/rewriting hacks in Rails are probably what convinced me that I do not like ruby. If you truly care about programmer efficiency, you probabl…

See also Clamato. http://clamato.net/

Re: Wherein Javascript borrows a language feature from Arc

#14

Post by cabalamat »

ynniv wrote: post #8
WilliamLP wrote: post #3

> geolocator.getLatLng("Forest Park, St. Louis, MO", function(center) { > displayMapAt(center, 14); > }); To my eyes, that solution is just fine. I don't think I'll ever be swayed to believe that adding on layers of indirection to JavaScript code for the sake of "syntactic goodness" is rationally motivated by leading to more practical power for actually solving problems.

Agreed. If you're writing something in a web browser, use sane JavaScript. Every time I have done something "fancy" with a language, there has been a large hidden cost later on, be that complicated debugging sessions, new hire training, or unintended side effects. Terrible syntax/rewriting hacks in Rails are probably what convinced me that I do not like ruby. If you truly care about programmer efficiency, you probabl…

I agree. The beauty of software systems is they can be made as complex as the programmer can imagine; this is also the horror of software systems.

All software should be as complex as it needs to be to do the job, and no more so (where complex means the cognitive load necessary to understand it). Unfortunately 99% of programmers and 100% of programmers' managers don't understand this (both numbers are probably correct to the nearest integer, in my experience).

Re: Wherein Javascript borrows a language feature from Arc

#16

Post by scott_s »

mdemare wrote: post #6

Clojure has #(+ % 10) for Arc's [+ _ 10]. Does anyone know if Arc inspired Clojure, or whether there's prior art for this syntax?

I think the convention predates both. boost::bind for C++ does something similar: http://www.boost.org/doc/libs/1_40_0/libs/bind/bind.html

Re: Wherein Javascript borrows a language feature from Arc

#17

Post by scott_s »

Can someone explain why this:

  geolocator.getLatLng("Forest Park, St. Louis, MO", displayMapAt);
Is better than this?

  displayMapAt(geolocator.getLatLng("Forest Park, St. Louis, MO"));
That is, why is it more sensible for getLatLng to accept a callback function that will accept its result, when one can just pass its result to a function?

Re: Wherein Javascript borrows a language feature from Arc

#18

Post by abecedarius »

scott_s wrote: post #17

Can someone explain why this: geolocator.getLatLng("Forest Park, St. Louis, MO", displayMapAt); Is better than this? displayMapAt(geolocator.getLatLng("Forest Park, St. Louis, MO")); That is, why is it more sensible for getLatLng to accept a callback function that will accept its result, when one can just pass its result to a function?

I expect the call to geolocator requires a network round-trip, with displayMapAt getting scheduled to be called when the result appears; meanwhile your code can do other things. (I'm not familiar with this API, though; I could be wrong.)

Another way to do this sort of thing, that might feel more composable: have geolocator.getLatLng() return a 'promise' object that will be asynchronously resolved.

Re: Wherein Javascript borrows a language feature from Arc

#19

Post by [deleted] »

scott_s wrote: post #17

Can someone explain why this: geolocator.getLatLng("Forest Park, St. Louis, MO", displayMapAt); Is better than this? displayMapAt(geolocator.getLatLng("Forest Park, St. Louis, MO")); That is, why is it more sensible for getLatLng to accept a callback function that will accept its result, when one can just pass its result to a function?

[deleted]
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