Template strings as a template language.

Thomas thomasjamesfoster at bigpond.com
Mon Sep 14 16:23:25 UTC 2015


Sorry, I sent that before I saw your other explanation. 

On a second look that function does work pretty well. The use of Function still means strings are being evaluated at runtime, but I agree that it's safer/better than eval (though I'm not sure why CSP would still like it over eval).

Have you any plans to make the String.prototype.template function a proposal?

Thomas

> On 15 Sep 2015, at 1:52 AM, Andrea Giammarchi <andrea.giammarchi at gmail.com> wrote:
> 
> again, Function **is** better and different than eval, but I see this conversation is bringing nothing so I'll just stop explaining.
> 
> Regards
> 
>> On Mon, Sep 14, 2015 at 3:47 PM, Thomas <thomasjamesfoster at bigpond.com> wrote:
>> Doesn't the code in that gist create functions at runtime from strings? If so that's not any better than eval. 
>> 
>>> On 14 Sep 2015, at 8:50 PM, Andrea Giammarchi <andrea.giammarchi at gmail.com> wrote:
>>> 
>>> sorry, early send (I think it was a ctrl+return ? ) ... I was saying ..
>>> 
>>> without using eval and already discussed months ago:
>>> https://gist.github.com/WebReflection/8f227532143e63649804
>>> 
>>> it's based on the glorious `with` statement and it works like a charm
>>> 
>>> Regards
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>>> On Mon, Sep 14, 2015 at 11:49 AM, Andrea Giammarchi <andrea.giammarchi at gmail.com> wrote:
>>>> without using eval, discussed already months ago
>>>> 
>>>> 
>>>>> On Mon, Sep 14, 2015 at 6:03 AM, Thomas <thomasjamesfoster at bigpond.com> wrote:
>>>>> For those interested, this gist better shows what's being discussed: https://gist.github.com/thomasfoster96/193e7c08aae499f810a1
>>>>> 
>>>>> Ron: Yes, that's already possible - but tagged template strings don't really offer much of an advantage over a function as far as templating goes (IMHO).
>>>>> 
>>>>> Thomas
>>>>> 
>>>>> On 14 Sep 2015, at 11:04 AM, Ron Buckton <Ron.Buckton at microsoft.com> wrote:
>>>>> 
>>>>>> This is theoretically possible:
>>>>>> 
>>>>>> ```
>>>>>> let t = $template`
>>>>>>   ${$item.permalink}
>>>>>>   ${$each($item.comments)`
>>>>>>     ${$parent.permalink}
>>>>>>     ${$if($item.title)`
>>>>>>       ${$parent.permalink}
>>>>>>     `}
>>>>>>   `}
>>>>>> `;
>>>>>> let s = t(data);
>>>>>> ```
>>>>>> 
>>>>>> ...given an adequate implementation using proxies (to create bindings for e.g. `$item.permalink` for later evaluation) and tagged template functions. Whether or not this would make for a reasonable implementation is left to the reader.
>>>>>> 
>>>>>> Ron
>>>>>> From: Isiah Meadows
>>>>>> Sent: ‎9/‎13/‎2015 4:15 PM
>>>>>> To: Mark S. Miller
>>>>>> Cc: Bob Myers; es-discuss
>>>>>> Subject: Re: Template strings as a template language.
>>>>>> 
>>>>>> On Sun, Sep 13, 2015 at 7:09 PM, Mark S. Miller <erights at google.com> wrote:
>>>>>> >
>>>>>> >
>>>>>> > On Sun, Sep 13, 2015 at 8:58 AM, Bob Myers <rtm at gol.com> wrote:
>>>>>> >>
>>>>>> >> Templating languages typically "compile" templates into functions through
>>>>>> >> various lexical transformations.
>>>>>> >>
>>>>>> >> Consider a template file foo.tem:
>>>>>> >>
>>>>>> >> ```
>>>>>> >> My name is ${https://na01.safelinks.protection.outlook.com/?url=this.name&data=01%7c01%7cron.buckton%40microsoft.com%7ce705066eae3849ee21f008d2bc913033%7c72f988bf86f141af91ab2d7cd011db47%7c1&sdata=CY6YpX1n5jLScYGX2W1tIi2ndGlA7WI8ZTJUZjDL2Gw%3d}.
>>>>>> >> ```
>>>>>> >>
>>>>>> >> Lexically transform this into
>>>>>> >>
>>>>>> >> ```
>>>>>> >> function foo() {
>>>>>> >>   return `My name is ${this.name|}.`;
>>>>>> >> }
>>>>>> >>
>>>>>> >> Then invoke the template as eg
>>>>>> >>
>>>>>> >> ```
>>>>>> >> foo.call({name: 'Bob'})
>>>>>> >> ```
>>>>>> >>
>>>>>> >> Having said that, I doubt if ES6 template strings serve as a useful basis
>>>>>> >> for a full-fledged templating system. To take just one basic example, how
>>>>>> >> would one implement the equivalent of `{{#if}}`?
>>>>>> >
>>>>>> >
>>>>>> > What does `{{#if}}` mean?
>>>>>> >
>>>>>> 
>>>>>> An example from Handlebars' website (which is likely where he drew the
>>>>>> syntax from):
>>>>>> 
>>>>>> ```
>>>>>> {{permalink}}
>>>>>> {{#each comments}}
>>>>>>   {{../permalink}}
>>>>>> 
>>>>>>   {{#if title}}
>>>>>>     {{../permalink}}
>>>>>>   {{/if}}
>>>>>> {{/each}}
>>>>>> ```
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> >>
>>>>>> >>
>>>>>> >> Bob
>>>>>> >>
>>>>>> >>
>>>>>> >> _______________________________________________
>>>>>> >> es-discuss mailing list
>>>>>> >> es-discuss at mozilla.org
>>>>>> >> https://na01.safelinks.protection.outlook.com/?url=https%3a%2f%2fmail.mozilla.org%2flistinfo%2fes-discuss&data=01%7c01%7cron.buckton%40microsoft.com%7ce705066eae3849ee21f008d2bc913033%7c72f988bf86f141af91ab2d7cd011db47%7c1&sdata=Vk9C%2fonHktgLCsW%2f395PrpBWefRcs6XFqJk7HTVbunE%3d
>>>>>> >>
>>>>>> >
>>>>>> >
>>>>>> >
>>>>>> > --
>>>>>> >     Cheers,
>>>>>> >     --MarkM
>>>>>> >
>>>>>> > _______________________________________________
>>>>>> > es-discuss mailing list
>>>>>> > es-discuss at mozilla.org
>>>>>> > https://na01.safelinks.protection.outlook.com/?url=https%3a%2f%2fmail.mozilla.org%2flistinfo%2fes-discuss&data=01%7c01%7cron.buckton%40microsoft.com%7ce705066eae3849ee21f008d2bc913033%7c72f988bf86f141af91ab2d7cd011db47%7c1&sdata=Vk9C%2fonHktgLCsW%2f395PrpBWefRcs6XFqJk7HTVbunE%3d
>>>>>> >
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> -- 
>>>>>> Isiah Meadows
>>>>>> _______________________________________________
>>>>>> es-discuss mailing list
>>>>>> es-discuss at mozilla.org
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>>>>>> _______________________________________________
>>>>>> es-discuss mailing list
>>>>>> es-discuss at mozilla.org
>>>>>> https://mail.mozilla.org/listinfo/es-discuss
>>>>> 
>>>>> _______________________________________________
>>>>> es-discuss mailing list
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>>>>> https://mail.mozilla.org/listinfo/es-discuss
> 
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