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vermaseren / form

The FORM project for symbolic manipulation of very big expressions
GNU General Public License v3.0
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Segfault for local expression defined in terms of itself #164

Open jodavies opened 7 years ago

jodavies commented 7 years ago

The following program produces a segfault:

Local test = test + 1;
.end

Of course it is a bad program, but it would be helpful to catch the error gracefully and print an error message. Tested with the latest commit, fa1c759.

Thanks, Josh.

tueda commented 7 years ago

The segfault is due to (intentional) stack overflow at runtime. Please see #57. Related tricky cases are

L F = 1;
.sort
L F = F + 1;  * (= 2)
P;
.end
L F = 1;
L G = F + 1;  * (= 2)
P;
.end

They have to be valid as used in many programs.