-----Original Message----- From: Brian Lloyd [mailto:Brian@digicool.com] Sent: 13. juli 1999 23:47 To: 'Alexander Staubo'; Zope Mailing List (E-mail) Subject: RE: [Zope] Defining variables
Currently we have REQUEST.set(). This is nice, but I think there is a need for a general-purpose variable namespace that isn't related to REQUEST (plus the fact that typing "REQUEST.set(...)" all the time isn't so cool).
I have one specific case where it's simply arduous having to mix real REQUEST variables -- meaning those that come in through the query string or form data -- with actual request-related variables.
How about adding something like _.set()?
-- Alexander Staubo
Doesn't the Let tag basically accomplish what you are asking for? From the Let tag docs:
The problem is that the let and with tags are block tags. If I have numerous variables, that's a lot of blocks! Eg., <!--#let foo=1--> <!--#let foo=2--> <!--#let foo=3--> ... <!--#/let--> <!--#/let--> <!--#/let--> (And no, you can't convince to stop indenting. :-) Indenting is just part of the reason I think the "let" tag is inappropriate here. With the closing tag, that's just seven characters less than the REQUEST.set() alternative! Plus line break, that's actually five characters gained. Not much typing saved there. <!--#call "REQUEST.set('f', 1)"--> <!--#let f=1--><!--#/let--> I essentially want something like <!--#set foo=1--> <!--#set foo=3--> <!--#set foo=4--> or, as I outlined, something like _.set().
The let tag:
is a new tag that lets you create blocks like:
<!--#in "1,2,3,4"--> <!--#let num=sequence-item index=sequence-index result="num*index"--> <!--#var num--> * <!--#var index--> = <!--#var result--> <!--#/let--> <!--#/in-->
Which yields:
1 * 0 = 0 2 * 1 = 2 3 * 2 = 6 4 * 3 = 12
The #let tag works like the #with tag, but is more flexible in that it allows you to make multiple assignments, and allows you to chain assignments, using earlier declarations in later assignments. Notice inthe ablove example, the 'result' variable is based on 'num' and 'index', both of which are assigned in the same #let expression.
Syntacticly, each argument to be evalulated in the head of the let tag must be seperated by a newline. Enclosing an argument in double quotes causes it to be evaluated by the DTML expression machinery. Un-quoted arguments are referenced by name.
Is it just me, or is this newline-separation syntax really crazy? How does the "let" tag handle multiline expressions? Why not just use commas? It would mean alienating those suckers who actually use commas in object ids, but that's not a huge loss. ;-)
Evaluation is in sequence with the result of earlier assignments available to later ones. Later assignments can also override earlier ones, which can be helpful for longer step-by-step calculations. The variables thus set are in effect for the life of the <!--#let--> block.
Brian Lloyd brian@digicool.com Software Engineer 540.371.6909 Digital Creations http://www.digicool.com
-- Alexander Staubo http://www.mop.no/~alex/ "He could open a tin of sardines with his teeth, strike a Swan Vestas on his chin, rope steers, drive a steam locomotive and hum all the works of Gilbert and Sullivan without becoming confused or breaking down in tears." --Robert Rankin, _The Book of Ultimate Truths_