Fixed over-eager leading backslash removal in Rascal outline

[rodinaarssen]

This solves an error in the outline of Rascal source files. Fixes #89.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

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[DavyLandman]

What happens now in case of an newline char? I can hardly imagine this fixing it, it such a small fix ;)

[rodinaarssen]

The regular expression that was changed in this PR intended to strip a leading backslash from the input, returning all characters trailing the backslash character. Instead, it would match against any backslash character in the input. New line characters are changed to a space in another overload of clean.

In the outline case, the string that is fed into clean is (cutting some corners), for a production P, "<p.syms>". In the failing example from #89, this corresponds to the string "\"BBB\\nBBB\"" (note that the backslash and n are separate characters here). The "leading backslash" clean overload would match against the \\ at index 4 and incorrectly return "nBBB\"". Now, it correctly returns the input.

[DavyLandman]

aah, right, it was for the case of an constructor named \if or \while. right :) thanks for explaining.