[Zope] <dtml-let> syntax

[Dieter Maurer]

Sebal writes:
 >     <dtml-let x=fmod(sequence-index,4))>
Three standard problems:

 1. attribute values for "let" that are not enclosed in "..."
    are treated as names and looked up:

      the code above tries to look up an object with
      name "fmod(sequence-index,4))" - quite hopeless

      You an expression rather than a name, enclose in "..."

 2. "sequence-index" is a valid DTML name but it is invalid
    in Python. More precisely, it is interpreted there
    as "sequence - index", a subtraction not a name.

    You need "_['sequence-index']"

 3. I never saw "fmod". Is it a Python built-in?
    Anyway, even if it were, it would not be available
    in DTML. (Some) Python built-in are available
    as attributes of "_". Other built-in functions
    are not available.


After this didactic excursions, a short answer to your question:

      <dmtl-let x="_['sequence-index'] % 4 == 0">

"%" (applied to numbers) is Python's "mod" operator.


Dieter