Exiting/Returning Early from a Template

[sqlalchemy-bot]

Migrated issue, originally created by Cody Taylor (@CodeMan99)

The documentation for Returning early from a template should suggest return an empty string. Otherwise python returns None and that may appear in your rendered template.

We should also consider adding a constant to represent exiting a template for two reasons.

1. Seeing return in the middle of a block of text can be very confusing since its normal syntax only holds meaning within a function or method.
2. Would ensure that the suggestion of returning an empty string allows holds true. The first time I saw None in my rendered template I was really confused.

I would be more than willing to implement this change, but I would not know where to add the suggested constant.

[sqlalchemy-bot]

Changes by Cody Taylor (@CodeMan99):

• edited description

[sqlalchemy-bot]

Michael Bayer (@zzzeek) wrote:

add the constant to mako/runtime.py, have it be available in templates which means its part of codegen.py in the symbols at the top (e.g. like UNDEFINED), then make the appropriate changes in the doc rst's. the docs have to include a ".. versionadded:: " directive to show that this constant isn't available in older versions of Mako also ( I can help format those).

[sqlalchemy-bot]

Michael Bayer (@zzzeek) wrote:

• reword the docs a bit
• PR is done, fixes Exiting/Returning Early from a Template #236

→ 6e78429

[sqlalchemy-bot]

Changes by Michael Bayer (@zzzeek):

• changed status to closed