Re: Refresh of XyWWWeb.U2 v119 (15 September 2006)

["Robert Holmgren" holmgren@xxxxxxxx]

** Reply to message from Harry Binswanger  on Sat, 16 Sep 2006
18:19:00 -0400


> Here's T.PGM encoded:

> XPLeNCODE v2.0
> b-gin [UNTITLED]
> {<}SX50,"File """+@UPR({<}IS50{>})+""" not found"{>}{<}EX{>}
> -nd
> XPLeNCODE

> I issued RUN T.PGM from the command line. It unaccountabl[y]
> gives the error message:
>  SX command requires a number. "File """+@UPR(«IS50»)+""" not found"
> And the error message makes sense to me: shouldn't it be SV not SX?

DECODE, then RUNCODE, this:

XPLeNCODE v2.0
b-gin [UNTITLED]
{<}SV50,filename.ext{>}{<}SX50,"File """+@UPR({<}IS50{>})+"""
 not found"{>}{<}PR@50{>}{<}EX{>}[cr|lf]
-nd
XPLeNCODE

I don't know what exactly you found "interesting" in that snippet -- the three
contiguous quotation marks? I'm "quoting quotes" within a concatenated
expression, to make them display. There are several ways to accomplish that
concatenation:

Xy3+ form:
++++>

Xy4 forms:
+++" not found">
+" not found">
+""" not found">

I employ the fourth (last) form in CALLORGO* -- because filename.ext is derived
from some other program (or conceivably from the command line), and is not
wrapped in quotes to begin with (if it were, I'd employ form three). CALLORGO*
is not a frame that you'd ever, in practice, use from the CMline; it's intended
as a child of another program... and indeed you'll find it sprinkled throughout
U2.

Apropos of nothing, form one indicates why Xy3-level XPL is prolix and
underpowered (by comparison).

-----------------------------
Robert Holmgren
holmgren@xxxxxxxx
-----------------------------