Beautiful mini language for outputing HTML in Python

http://shpaml.webfactional.com/examples

by iamelgringo • 17 years ago

92 73 17 years ago

shpaml.webfactional.com

apgwoz• 17 years ago

I'm not a big proponent of all of these new HTML replacers. They don't really buy you anything--this one just gets rid of angle brackets as far as I can see, and adds CSS style #id and .classname. Now, instead of angle brackets, we have to use tabs, or spaces, or some other delimiter (I saw | in there for continuing a line).

The best way I've found of representing XML/XHTML or even HTML for that matter, is with X-Expressions--a subset of S-Expressions. But, they are most useful in a language that fully supports S-Expressions, like Lisp, since you can then use standard functions to generate your markup for you.

davidw2• 17 years ago

Yes, I think that for HTML, "better tools" is the right answer. HTML is something that can be shared between people with various backgrounds, skills, and toolsets. I can write it in Emacs on Ubuntu, and send it to some guy who will work on it in Windows with Notepad, who can send it to someone else who will open it with Chrome on a Mac.

These things might be ok for small, tight teams, but I don't see them as buying that much in the long term, as opposed to tools that let you be more productive with HTML.

mtomczak• 17 years ago

I believe that I see your point, and I would agree that the verbosity of HTML leads to sharability, and that is a strength.

But the verbosity is also one of its weaknesses for large projects; it adds a great deal of overhead in terms of keeping track of the tags, especially if the HTML needs to be re-arranged. And with no language-supplied rules for how much whitespace to use or where (beyond "all adjacent whitespace is compressed"), there is too much flexibility for a large team to work smoothly. My usage case doesn't mesh with your example, because I'm working in an environment with version control and multiple developers. The guy using Notepad will be told to get a tab-aware text editor, because his changes will mangle the whitespace in the file and lead to unnecessary noise when he commits.

When structure in your whitespace is already desired (to avoid making your version control noisy), you can leverage the fact that you are structuring the whitespace to make it a semantic element. This greatly decreases typing, makes the code easier to eye-scan, and allows details such as proper closing bracing to be left to the compilation tool and not to the developer. I agree with commenters who have noted that HAML has been proven useful for some developers.

I would categorize both SHPAML and HAML as tools that let you be more productive with HTML.

showell21• 17 years ago

SHPAML replaces angle brackets and close tags with space-based indentation and pipes. The CSS sugar for #id and .classname is completely optional, and obviously if you know CSS, then the syntax should be familiar.

I agree that there are plenty of other useful ways to represent XML/HTML.

SHPAML does require or even support tabs. The "|" is not for line continuation; it is to separate markup from content.

drhowarddrfine• 17 years ago

There's just something wrong about creating a language with a language to produce about in a third language. As Brian Kernighan told Dustin Hoffman one time, "Learn to code!".

nopal• 17 years ago

While your language^3 comment is technically true, this seems to be simply shifting one markup syntax to another, using a language to perform the translation.

In addition, using something like SHPAML requires knowledge of the final output syntax, so the person using it must already know how to code.

Edit: In reading my response, it seems too curt. I definitely see your point, but more so in contexts other than this.

showell21• 17 years ago

It is not a promise, or even a goal, of SHPAML that it will relieve you the burden of understand the final output syntax, whether that is HTML or HTML combined with some template language.

SHPAML users are expected to be literate in both HTML semantics and syntax. The semantics of HTML are not abstracted away at all. The syntax is only abstracted away where it is redundant.

As a couple folks have pointed out, HTML is a pretty simple language. The problem with HTML is not its lack of simplicity; it is its verbosity.

So, if you use SHPAML, you undeniably get the terseness of SHPAML and the powerful semantics of HTML. So the question then comes down to simplicity. Does SHPAML eliminate too much of the simplicity of HTML syntax in trying to achieve terseness?

tpyo• 17 years ago

How did Hoffman and Kernighan meet?

julius_geezer• 17 years ago

Pulling your leg. Hoffman, who had learned in the "method acting" schools, apparently stayed up all night to look properly harrowed for a scene. Laurence Olivier, playing opposite, is said to have told him something like "Why don't you try acting, my boy? It's so much simpler."

kashif• 17 years ago

What is the problem with using one language to produce another? How do you think your primary programmin language gets converted to assembly and then to machine code?

As far as I am concerned this is a useful abstraction on a trivial problem.

mbreese2• 17 years ago

The problem is that this is a trivial problem. Why add an abstraction on top of something that is already so simple?

Confusion• 17 years ago

Right, just like creating Python with C is 'just wrong' if you're going to be writing applications that produce HTML?

capablanca• 17 years ago

I no longer fall for languages that only change the syntax for something the author thinks it's cuter...

irrelative• 17 years ago

I agree. Nor do I call them beautiful.

wensing4• 17 years ago

Is it just cuter if it means less typing?

timdorr• 17 years ago

The difficulty of programming isn't from having to type too much, it's from solving problems.

pgbovine• 17 years ago

i use Markdown (http://daringfireball.net/projects/markdown/) regularly rather than directly writing HTML. like this thing, it's also just syntactic sugar, but it's well-designed and makes it so that i can concentrate on writing and not on formatting syntax. my raw text files are much more source-control friendly, since the diffs are clean.

silentbicycle4• 17 years ago

Markdown is different, though. Rather than trying to cram HTML into a yet another pseudo-programming syntax, it tries to generate HTML that matches common plaintext-formatting conventions. You might not guess Markdown-formatted text was written with a formal markup language in mind.

FWIW, there's a C implementation of Markdown called "discount" (http://www.pell.portland.or.us/~orc/Code/discount/) which is crazy fast, easy to embed, and has a couple nice extensions.

(Also, "SHPAML"? Gross.)

olalonde• 17 years ago

Right. I don't see any use case for this syntax especially that modern IDEs offer auto completion .

showell21• 17 years ago

Modern IDEs inject close tags and angle brackets into the source document. The SHPAML preprocessor injects that syntax into the target document. The use case applies to the person who wants clean syntax in the source document and executable syntax in the target document.

silentbicycle4• 17 years ago

While it's less significant for HTML than code, verbose languages are problematic during reading as well as writing.

While generating stub code for class declarations, getters, setters, etc., can help with writing boilerplate-y OO code quickly, anyone trying to read it to decipher its intent will still have to deal with all the clutter. That's more likely to cause problems in the long run.

snprbob86• 17 years ago

What are your thoughts on HAML and SASS? They aren't simply "cuter" they are a full-blown templating and stylesheet meta language. I've been using SASS in a Python project and love it. The more I use SASS, the more envious I grow of people who get to use HAML.

I was intending on eventually writing my own HAML-type language in Python, but it looks like with SHPAML, I won't have to. Because SHPAML supports raw HTML and doesn't do anything with the {} characters, I can use SHPAML in conjunction with my existing Jinja2 templates. This will enable me to convert my templates organically. The intermediate HTML/Jinja representation doesn't need to appear on disk, so this really looks like an easy way to add "cute" HTML syntax to and existing Python text templating language.

andrewcooke2• 17 years ago

this could almost be embedded, which would be much cooler i think. you'd have to define objects with names from html tokens and do some ugly hacking with python's operators. you'd also have to add something other than space between strings (a "+" might be ok).

but once you've done that, this could be very neat. no processors - just constructing html in python.

(i don't know if this sounds crazy or not, but you can see the same kind of approach in lepl, which i wrote. the main problem is operator precedence.)

showell21• 17 years ago

Other folks have tried to solve the problem of cleanly creating HTML from within Python itself, which I think is what you are alluding to. It's not a goal for me. To the extent that my markup is pretty static, but the content is dynamic, I try to use a templating language beneath SHPAML. If the structure of the page itself needs to be dynamic, then I probably want to serve up JSON to the browser, not HTML, and then let Javascript manipulate the DOM, taking HTML (and SHPAML) mostly or completely out of the equation. I think there are some cases when you want the power of the server-side programming language to help you build documents, but that is often a smell that your documents are overly complex, or that your templating language is weak, or that your UI is too complicated for browsers, or that your client-side code isn't pulling its weight, etc.

andrewcooke2• 17 years ago

so, if i understand right, you think it's better to implement it as a separate language to stop people doing things that you don't think they should do, or think they don't need?

apart from stopping people from doing things, are there any what you might call "positive" reasons - advantages - to doing it your way?

Jim_Neath• 17 years ago

I like HTML. I like the way it looks. I like writing it.

On the other hand, I don't like new DSLs for writing what is already a simple markup language.

eru• 17 years ago

HTML is a bit verbose.

RyanMcGreal• 17 years ago

> If HTML were truly awesome, then you would not have Wikipedia; you would have Htmlpedia.

I don't buy this. The problem with HTML is not that it isn't expressive enough or that it's too hard to use; it's that arbitrary user code can easily compromise the integrity of your website.

showell21• 17 years ago

I wrote the comment about Wikipedia only to illustrate that HTML, like any standard, is not perfect for every use case.

I find HTML expressive and generally easy to use. I wrote SHPAML in a way that I hope preserves the useful expressiveness of HTML, while eliminating some of the 1990s-style syntax.

nir3• 17 years ago

Why are most comments here negative? HAML already shown this technology does have value to a significant amount of people. Someone took the time to write this, seems to have done a pretty nice job and is releasing it for anyone to use. I can't see why anyone would feel the need to put it down in the comments. If you don't like, just don't use it.

njharman• 17 years ago

Because;

1) by posting link to it on discussion site you are assumed to be soliciting opinions.

2) it was called "beautiful". A claim so false as to require immediate and forceful contradiction.

nir3• 17 years ago

1) As an HN submission, it's certainly better than most. Anything with code in it beats "Startup lessons from J-Lo".

2) Beauty is a matter of taste. It might not be the Bar Rafaeli of languages, but I wouldn't think it's so ugly as to require "forceful contradiction".

showell21• 17 years ago

I did not post the link here, nor did I call anything "beautiful," but I presume that the reason the original poster posted the link on a "discussion" site was to solicit "discussion." Immediate and forceful contradiction does not equate to discussion, even when the claim is "so false" as this one.

dpatru• 17 years ago

One of the primary benefits I get from HN is the pro and con discussion of technology, especially if it's something I might want to use. If there are good reasons not use a technology, then I would rather hear about them before I rediscover them from my own experience.

showell21• 17 years ago

As the author of SHPAML, I have no problem with all the negative comments about lightweight syntax abstractions, as I've seen all the same arguments written against HAML. Most of the critics of SHPAML have probably never actually used it, nor do I expect them to if they don't share the same pain points as I do. Nowhere do I make any claims that SHPAML is going to cure all problems. It does make producing HTML easier for me.

dan_sim• 17 years ago

Is HTML that hard to write?

wensing4• 17 years ago

If you don't use something like TextMate snippets (or some other auto-completion), then it's definitely overly-time-consuming IMHO.

olegk• 17 years ago

Good HTML is hard to write. Look up HTML source of several major websites, and you will see how badly indented it is. 95% of them won't validate. Look at this page. It doesn't even have a doctype.

wensing4• 17 years ago

That's largely because it's hard to care.

Browsers don't halt when fed less-than-good HTML the same way an interpreter/compiler dies when fed bad syntax.

showell21• 17 years ago

The movitation behind SHPAML isn't necessarily just to make the markup easier to write; it also tries to make it easier to read.

mattmcknight• 17 years ago

I prefer XML Builder templates (in Rails or Groovy) to this approach. It's similar, but SHPAML just drops enough stuff to have to be learned. You basically already know how to write Builder, it's that simple.

jmonegro2• 17 years ago

I don't see why I would use that over this: http://lab.xms.pl/markup-generator/ Not only does it have the same syntax (with some improvements), but it also gives me the CSS to work with. AND I don't have to install python. Hooray.

showell21• 17 years ago

You don't technically need to install python to use SHPAML. You can try it online:

http://shpaml.webfactional.com/tutorial/7

SHPAML is mostly targeted at Python users for now. If you are not using Python, but you like the idea of having a syntax layer on top of HTML, then you should consider other solutions like the markup generator or haml.

jmonegro2• 17 years ago

Still, the markup generator gives you CSS markup as well.

nicpottier• 17 years ago

I kinda like it.. sure it is one more level of abstraction, and good editors will help with the tag balancing, but let's face it, (X|HT)ML syntax isn't exactly natural to write, and I say this despite having written it by hand for well over a decade.

This probably appeals more to people who have made the Python jump and like that whitespace means something, as that's what really makes it terse.

showell21• 17 years ago

SHPAML is definitely targeted at Python users and people who like meaningful whitespace (and associated terseness).

Glad you like it! I have also been hand writing HTML for well over a decade too (as well as other means of producing HTML), so my goal in SHPAML was simply to relieve pain points for an everyday task. It has worked for me.

amitu• 17 years ago

One reason to use this would be to get well indented HTML.

Finding the potentially missing closing </div> tag has been a common problem I have seen some people face.

teehemkay• 17 years ago

The language may be prettier than HTML but the name looks rather ugly to me. Doesn't sound as bad though :-)

prodigal_erik2• 17 years ago

I'm disappointed they resorted to a one-way preprocessor. Is it really not feasible to make a first-class domain-specific language like this in Python?

showell21• 17 years ago

The reason I made SHPAML a one-way preprocessor is that my use cases haven't yet given me a compelling reason to write a round tripper, and preprocessing is simple to automate.

I do not know what your criteria are for judging a "first-class" DSL in Python, so I cannot comment on the feasibility. My goal was to create a simple markup language that maps well to HTML and plays nice with templates. SHPAML does that.

prodigal_erik2• 17 years ago

Sorry, I misread the title "Beautiful mini language for outputing HTML in Python" as a DSL to be embedded in Python code rather than a separate text file (which is actually language agnostic after the preprocessor is done).

wglb• 17 years ago

Browsers care about how html looks. We should think of html and css as the assembly language--generated by some server-side process.

Beautiful mini language for outputing HTML in Python

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