[BUG] FT attributes with value 0 (int) are ignored.

[pitvfx]

Important Notice
We do not provide support through GitHub issues. For community-based help, please use either:

• GitHub Discussions tab
• Our Discord channel

If you're reporting a bug, please continue with this template.

Describe the bug
Attributes fo FT with a numeric value of 0 are ignored. Changing to str "0" works, though.

Minimal Reproducible Example
Provide a minimal code snippet that reproduces the issue. This is crucial for us to understand and fix the bug quickly.

from fasthtml.core import to_xml
from fasthtml.components import Input

# ignored
num_input = Input(type="number", min=0, max=100)
txt_input = Input(type="text", minlength=0, maxlength=100)
print("min ignored:\n", to_xml(num_input),
      "minlength ignored:\n", to_xml(txt_input))


# accepted
num_input = Input(type="number", min="0", max=100)
txt_input = Input(type="text", minlength="0", maxlength=100)
print("min accepted:\n", to_xml(num_input),
      "minlength accepted:\n", to_xml(txt_input))

Output:

min ignored:
 <input type="number" max="100">

minlength ignored:
 <input type="text" maxlength="100">

min accepted:
 <input type="number" min="0" max="100">

minlength accepted:
 <input type="text" minlength="0" maxlength="100">

Expected behavior
That numeric values of 0 are accepted for FT attributes.

Environment Information
Please provide the following version information:

• fastlite version: 0.0.13
• fastcore version: 1.7.19
• fasthtml version: 0.8.0

Confirmation
Please confirm the following:

• I have read the FAQ (https://docs.fastht.ml/explains/faq.html)
• I have provided a minimal reproducible example
• I have included the versions of fastlite, fastcore, and fasthtml
• [x ] I understand that this is a volunteer open source project with no commercial support.

Additional context
Add any other context about the problem here.

Screenshots
If applicable, add screenshots to help explain your problem.

[Phrogz]

Likely the same problem this prevents me from creating <option value="">select a value</option>:

to_xml(Option("select a value", value=""))
#=> "<option>select a value</option>"

At least with 0 we have the workaround of using str(num) to get the result.

---

Edit: Actually, not the same problem. Empty strings are explicitly omitted in xml.py on this line:

sattrs = ' '.join(_to_attr(k, v) for k, v in attrs.items() if v not in (False, None, '') and (k=='_' or k[-1]!='_'))

A workaround for the empty-value case—not the problem in this bug—is to use value=True which will output <option value>…</option>, which the browser treats the same as an empty value.

[Phrogz]

Tip! (0 in (False)) == True

I think if v not in (False, None, '') and … needs to become:

if v is not False and v is not None and v is not '' and …

or if you're a golfer:

if all(v is not x for x in (None, False, "")) and …