Thanks!
I usually do in your suggested way, and I'm with you. But in this special
case, I feel the user of my module could find a bit weird to write
var st = require('simpletags');
st.html(st.head(st.title('...')), st.body(st.h1(....))
instead
html(head(title('....')), body(h1('...'))
in a controlled way (only in its own module). I want to give him/her an
option. Ruby has it (as an option, too). It's the first time I found I
needed it in Node.js. Usually, I assert "Ruby ceremony > Javascript/Node.js
ceremony", but now, I was trapped by this issue.
My best solutions:
a)
var st = require(...); // and use with st.h1, st.h2...
b)
require('simpletags').exportsTo(global); // maybe in browser I could export
to windows directly in the module
c)
var simpletags = require('simpletags');
eval(simpletags.exportLocalCode()); // where .exportLocalCode returns a
String with "var h1 = simpletags.h1; ... "
c2)
var st = require('simpletags');
eval(st.exportLocalCode('st')); // the local variable name 'st' should be
informed to be used in var ...= .... string result
On Sat, Jul 7, 2012 at 10:38 AM, Mariusz Nowak <[email protected]> wrote:
> In modules you can achieve the same by assigning function to global: e.g.
> `global.foo = function () { .. }` it will work same as `this.foo = function
> () { ... }` in REPL. but I would strongly discourage this, relying on
> global scope is bad practice.
>
> I'd say that unless you're using regular require/export logic to share
> objects between modules, you're doing something wrong. Try to think just
> with require/exports and then you should quickly find way home. See how
> module relations in other packages work.
>
> --
> Mariusz Nowak
> https://github.com/medikoo
> http://twitter.com/medikoo
>
>
> On Saturday, July 7, 2012 3:18:51 PM UTC+2, ajlopez wrote:
>>
>> Thanks for the suggestion!.... but... I missing some part of your answer.
>>
>> I guess I understand the difference btw global, this.property, and var
>> local. And then, I understand why it not works. What I don't understand is
>> how to circumvent/solve the problem. I don't know if your answer is:
>>
>> a- " you'll get the answers :) " and then, you will know that it's
>> impossible to solve, or too weird
>> b- you'll get the answers :) " and it's possible in this (simple)
>> way.....etc...
>>
>> AFAIK, it's "a". Am I right?
>>
>> My problem is:
>>
>> - module1 requires module2
>> - I want to use the exposed functions of module2 as they were defined in
>> module1, using dynamic names. That is, it's not a solution
>>
>> var module2 = require('module2');
>> var Function2 = module2.Function2;
>>
>> Usually, I did a bit of experiment at REPL. I found that this works:
>>
>> var name = 'Function2';
>> this[name] = ...
>>
>> var obj = new Function2(); // without using this
>>
>> BUT it's only works at REPL. So, encouraged by this discovery (I expected
>> it will not work), I hoped to make it works in other context.
>>
>> Now, I understand why it is work in REPL. Notably, in REPL
>>
>> this == global
>>
>> so it's possible to emulate
>>
>> var foo = ...
>>
>> with something like (pseudocode)
>>
>> name = 'foo'
>> var [name] = .....
>>
>> writing
>>
>> name = 'foo';
>> this[name] = ...
>>
>> and then foo is available "as if it is" a local var.
>>
>> But inside a running .js, this is not equal to global. I was tricked by
>> REPL ;-)
>>
>> So, the better solution I found so far is to put something like this in
>> module1:
>> // http://stackoverflow.com/**questions/5625569/include-**
>> external-js-file-in-node-js-**app<http://stackoverflow.com/questions/5625569/include-external-js-file-in-node-js-app>
>>
>> var fs = require('fs');
>> var vm = require('vm');
>>
>> var includeInThisContext = function(path) {
>> var code = fs.readFileSync(path);
>> vm.runInThisContext(code, path);
>> }.bind(this);
>>
>> includeInThisContext(__dirname + '/module2.js');
>>
>> console.log(foo); // it's defined
>>
>> where module2 define foo:
>>
>> foo = {};
>>
>> BUT IN MY CASE, module2 doesn't define the functions at its own context:
>> https://github.com/ajlopez/**SimpleTags/blob/master/lib/**simpletags.js<https://github.com/ajlopez/SimpleTags/blob/master/lib/simpletags.js>
>> it uses an array to dynamically define and export functions. I never have
>>
>> function h1() {
>> }
>>
>> function h2() {
>> }
>>
>> defined at module2 context. And I don't want this. My DSL defines a
>> function for each HTML tag.
>>
>> Now, I want to have these dynamically defined functions from
>> module2 accessible in outer module1, as they were local to it.
>>
>> I could write inside my module,
>>
>> var h1 = makeTag('h1');
>> var h2 = makeTag('h2");
>> ...
>> ....
>>
>> for dozens of tags, and then use something like includeInThisContext....
>> but I feel it's too weird.
>>
>> Apparently, my problem is: I didn't find a way to define a local var with
>> a dynamic name.
>>
>> The original DSL in Ruby:
>> https://github.com/dlitvakb/**deklarativna/blob/master/test/**
>> test_deklarativna.rb<https://github.com/dlitvakb/deklarativna/blob/master/test/test_deklarativna.rb>
>>
>> use "include dslmodule". And inside the dsl module, it defines
>> dynamically named functions at module top level. So the functions are
>> automatically available to the module that makes the includes.
>>
>> That is the "trick" I didn't found how to emulate in
>> Node.js/require/CommonJS world.
>>
>> Some links in my research:
>> http://stackoverflow.com/**questions/5833978/javascript-**
>> how-to-use-dynamic-local-**variables<http://stackoverflow.com/questions/5833978/javascript-how-to-use-dynamic-local-variables>
>> http://stackoverflow.com/**questions/5094862/how-do-i-**
>> access-a-local-variable-**dynamically-via-a-string-form-**of-its-name-fro<http://stackoverflow.com/questions/5094862/how-do-i-access-a-local-variable-dynamically-via-a-string-form-of-its-name-fro>
>> http://stackoverflow.com/**questions/598878/how-can-i-**
>> access-local-scope-**dynamically-in-javascript<http://stackoverflow.com/questions/598878/how-can-i-access-local-scope-dynamically-in-javascript>
>> http://stackoverflow.com/**questions/2336508/javascript-**
>> get-access-to-local-variable-**or-variable-in-closure-by-its-**name<http://stackoverflow.com/questions/2336508/javascript-get-access-to-local-variable-or-variable-in-closure-by-its-name>
>> http://stackoverflow.com/**questions/1119335/javascript-**
>> local-variable-declare<http://stackoverflow.com/questions/1119335/javascript-local-variable-declare>
>>
>> The better approach I found in these links is to use eval (!!??):
>> eval("var "+name+ " = ....");
>>
>> Am I right? the only ways are the above ones? Or is another way?
>>
>> Any suggestions?
>>
>> Angel "Java" Lopez
>>
>>
>> On Sat, Jul 7, 2012 at 9:27 AM, Mariusz Nowak <[email protected]>wrote:
>>
>>> @ajlopez get to know how variable scoping in JavaScript works (what is
>>> global, how this and how local variable works), and you'll get the answers
>>> :)
>>>
>>>
>>> On Saturday, July 7, 2012 2:11:56 PM UTC+2, ajlopez wrote:
>>>>
>>>> Hi people!
>>>>
>>>> A very simple question. When I write in the Node repl:
>>>>
>>>> this.foo = 'bar';
>>>> console.log(foo);
>>>>
>>>> it's ok, foo is defined. But writing that code in file.js and running
>>>>
>>>> node file.js
>>>>
>>>> then foo is not defined.
>>>>
>>>> Or require('file.js'), then foo is not defined.
>>>>
>>>> Any way to define a variable in the "current context"? Apparently,
>>>> "this" properties and "current context" top variables are the same in REPL,
>>>> but they are not the same in .js, or inside a required module.
>>>>
>>>> I want to do this in a dynamic way:
>>>>
>>>> name = 'foo';
>>>> // ...
>>>> this[name] = 'bar';
>>>>
>>>> so
>>>>
>>>> foo = 'bar';
>>>>
>>>> is not a solution in my context.
>>>>
>>>> I could use:
>>>>
>>>> global[name] = 'bar';
>>>>
>>>> but I want to expose the new "current context" top variables only in my
>>>> "current context" without pollute the global environment.
>>>>
>>>> I encountered this problem when coding a simple HTML DSL:
>>>> https://github.com/ajlopez/**Sim**pleTags/blob/master/test/**expor**
>>>> tsTo.js<https://github.com/ajlopez/SimpleTags/blob/master/test/exportsTo.js>
>>>> I want the DSL functions to be accesible as:
>>>>
>>>> require('simpletags').**exportsT**o(????); // ???? == global? this?
>>>> Now, I should use global to make it works in any situation
>>>>
>>>> then, use the exported function as functions in current context:
>>>>
>>>> html(body(h1("TheNextBigThing"****)));
>>>>
>>>> instead
>>>>
>>>> var st = require("simpletags");
>>>>
>>>> st.html(st.body(st.h1("**TheNext**BigThing")));
>>>>
>>>> Any other way?
>>>>
>>>> TIA
>>>>
>>>> Angel "Java" Lopez
>>>> http://ajlopez.wordpress.com
>>>> @ajlopez
>>>> gh:ajlopez
>>>>
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>>
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