POC automate parser grammar

[ichiriac]

related to prettier/plugin-php#1053 - should be released on v3 stable if this issue is validated

[alexander-akait]

I think we can do this for 4 version, i think our parser is very stable in 98% cases, so we just need some fixes and implementations and release stable 3 version, also it is allow accumulate tests and don't break ast for new parser

[ichiriac]

ok, let it be for the v4 - actually I'm not sure it can be done - see here the progress : https://github.com/glayzzle/php-parser/tree/poc-yaccs/poc