Translate with malformed vector leads to crash

[WJWH]

Trying to compile the following code will cause extopenscad to consume all available memory until it crashes with an "out of memory" error.

translate([-,0,0]) cube(1);

Note there being just a minus as the first element of the vector. I believe proper behavior would be to detect this and give a more informative error message.

[julialongtin]

Reproduced on the current version. investigating.

[julialongtin]

also reproduced by:

echo ((-)); echo ([-]);

[julialongtin]

and echo((+));

[WJWH]

Perhaps it believes there to be a number following it, causing some sort of infinite recursion? I had a quick look through code and the most likely thing I could find was https://github.com/colah/ImplicitCAD/blob/master/Graphics/Implicit/ExtOpenScad/Parser/Expr.hs#L177, but I must admit I don't know this code (or just Parsec in general) well enough to make a proper fix.

As an aside, this is one of the oldest GH issues I've filed and I think it's super cool that people are looking at it now. Much appreciation for that.

[julialongtin]

and echo([ for (a = [1 : 4]) [a, a * a] ]);

[julialongtin]

almost-complete rewrite of the expression parser. quite a bit faster (4-600 times, depending on the test!), and all of these generate syntax errors now.

Problem solved. :)