#do lvar = expression for very big expression

[tueda]

Because the Print statement can't be used for different files (see #245), what only one can do is to write terms in the preprocessor. To do this, one needs to enumerate the terms. At first glance #do lvar = expression seems to be used for this purpose, but unfortunately looks a bad idea for very big expressions. All the terms are loaded into a $-variable before the iteration begins. Easily "StageSort" happens. We know that it is too buggy and dangerous for $-variables (e.g., #211).

To me, loading the whole expression into a $-variable sounds overkill. If the copying the expression is really required to protect the original expression, then in principle this can be done into a temporary disk space like spectators, not into memory space, and then the preprocessor can start the iteration for the copied expression on disk.

[tueda]

Indeed, I need keeping brackets, so #do lvar = expression doesn't work and maybe I go for FillExpression. But still #do lvar = expression for very big expression would be a nice improvement.

[vermaseren]

What is needed is the write statement that acts similarly to #write, but then during execution. This would solve your problem. Of course, it would have much in common with the print “…” statement.

Jos

On 24 Nov 2017, at 15:14, Takahiro Ueda notifications@github.com wrote:

Indeed, I need keeping brackets, so #do lvar = expression doesn't work and maybe I go for FillExpression. But still #do lvar = expression for very big expression would be a nice improvement.

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