Handle `virtual` and `override` modifiers

[fvictorio]

This can't be done at the moment because the parser is not exposing this information. See ConsenSysDiligence/solidity-parser-antlr#2

When that is solver, we should handle these modifiers.

virtual is easy: we should just add the literal virtual after the visibility modifier (at least that's where it's placed in the examples).

override might be followed by some class specifiers, so that should be handled properly. How to do it will depend on how the parser exposes this information.

[mattiaerre]

can we close this issue now @fvictorio ?

[Janther]

@mattiaerre virtual works but override is still not handled

[juanfranblanco]

Is there are workaround or setting to avoid prettier deleting keywords? @mattiaerre As this maybe an issue with new keywords introduced in the future, different versions of solidity / antlr

[Janther]

Our plugin reprints the code from the AST that we get from the parser.
Every keyword is handled by a different rule.
So is really difficult to predict how the parser will decide to implement each keyword or how the current parser will react to new syntax.
We are reactive in this sense. We have to wait until the parser evolves before we know how it will affect the printing process.
Currently the only way to avoid prettier to mess with an unsuported keyword is to add the comment prettier-ignore before the line. This will not avoid the parser trying to parse or even failing the parsing process, it will only tell prettier to choose the original text over the AST node.

[Janther]

if the problem continues the whole file could be skipped by adding it to .prettierignore

[juanfranblanco]

Ok thanks, I think I will disable it by default for the time being as I just had another issue, and let "advanced" users enable it themselves until things settle a bit. Keep the good work ! juanfranblanco/vscode-solidity#168

Edit: I am just adding a setting to select the formatter None, Prettier and set Prettier as the default.