Syntax error with ${{'foo':'bar'}}

[sqlalchemy-bot]

Migrated issue, originally created by Anonymous

This works fine:

<li>${dict(method="get")}</li>

This crashes:

<li>${{'method':'get'}}</li>

mako.exceptions.SyntaxException: (SyntaxError) unexpected EOF while parsing (line 1) ("{'method':'get'") in file [...]

---

Attachments: mako_braces.diff | mako_ticket20.diff | mako-lexer-fix.diff

[sqlalchemy-bot]

Michael Bayer (@zzzeek) wrote:

yeah unfortunately there will always be some issues like this one, it should be pretty obvious why this one is occurring (you know, its looking for a bracket). there is some logic to handle things like this which is already accounting for strings like ${"}") but thats because its counting quotes...i can look into it further but unless i rewrote the entire python parser there will always be things like this which can slip through (also, a typical MVC setup wouldnt really be declaring dictionaries inside of templates/expressions anyway, though thats not a 100% excuse.....)

id like to see how other template languages handle phrases like that one.

[sqlalchemy-bot]

Changes by Michael Bayer (@zzzeek):

• changed assignee from "zzzzeek" to "zzzeek"

[sqlalchemy-bot]

Anonymous wrote:

I've simplfied the example for the demonstration, but following this example, this is not an excuse, not even 1%. :)

From a Pylons point of view, I'd be tempted to do the following:

${h.link_to_remote("Home", options={"url":h.url_for("home"), "method":"get"})}

How about extracting what's contained inside ${} as a string and do an eval() on the string ?

extracted = """h.link_to_remote("Home", options={"url":h.url_for("home"), "method":"get"})"""
print eval(extracted)
Home

Just an idea...

[sqlalchemy-bot]

P C (@pc) wrote:

Rather than fixing every such bug, may be a good idea to let user to increment number of braces if he needs. So that examples above writen as:

  ${{ h.link_to_remote("Home", options={"url":h.url_for("home"), "method":"get"}) }}
  ${{ {'method':'get'} }}
# So this would be also written as:
  ${{ " some } text " }}
# And maybe sometimes you will need:
  $` {'a': b, c: { 'e': 'f' }} `
# but this is better writen as (with space between braces "}"):
  ${{ {'a': b, c: { 'e': 'f' } } }}

I consider this is better than escaping braces someway:

  ${ h.link_to_remote("Home", options=\{"url":h.url_for("home"), "method":"get"\}) }
# or maybe
  ${ h.link_to_remote("Home", options={{"url":h.url_for("home"), "method":"get"}}) }

[sqlalchemy-bot]

Anonymous wrote:

Attached patch exploits codeop module to overcome this problem. This module is one that is used for interactive python sessions.

[sqlalchemy-bot]

Michael Bayer (@zzzeek) wrote:

unfortunately, many tests fail with the latest patch. If the patch can be repaired such that all tests pass, we can put it in. Mako is due for a release so this one might have to wait for another go-around....

[sqlalchemy-bot]

Anonymous wrote:

Tavis has the following suggestion from Cheetah. -MO

"I maintain a stack of enclosures (,[,{ to balance things out. See
getExpressionParts at line 1052 in Parser.py."

[sqlalchemy-bot]

Michael Bayer (@zzzeek) wrote:

yeah, i think an expansion of the current "quote counting" idea to just be a stack of enclosures is the most practical approach here. I had hopes for the "python compiler" approaches previously patched here but this would be more straightforward.

[sqlalchemy-bot]

Anonymous wrote:

Werkzeug ships a minimal template engine for some small scripts and it solved that problem the same way Ka-Ping Yee's old interpolation code did with a small modification for newer Python versions:

http://dev.pocoo.org/projects/werkzeug/browser/werkzeug/templates.py

see token_re and match_or_fail (and the code that calls it) around line 312.

[sqlalchemy-bot]

Michael Bayer (@zzzeek) wrote:

k, thats hopeful. i'm at energy level zero for mako these days so if someone wants to adapt that into a patch, that's a good path towards a fix.

[sqlalchemy-bot]

Anonymous wrote:

I took a crack at this; it's not the most beautiful solution, but it should be correct. Fixes #86 as well. Added simple tests, all the tests pass, and the suite is even a whopping 4ms faster!

Trac griped when I tried to attach a file, so patch here: https://gist.github.com/1713508

~ @eevee

[sqlalchemy-bot]

Michael Bayer (@zzzeek) wrote:

wow, that is really impressive ! as you can see, this bug has existed since day one and...ah someone else took a crack five years ago. I'll try running this across a huge pile of templates here and see what I get.

[sqlalchemy-bot]

Michael Bayer (@zzzeek) wrote:

awesome works great !!

1efbc03

[sqlalchemy-bot]

Changes by Michael Bayer (@zzzeek):

• changed status to closed