Comments
Comments in FOL code DON'T follow the traditional style of line (//) comment forms.
Normal comments
They are represented with backtick.
SINGLE_LINE_COMMENT :
`this is a single line comment`
MULTI_LINE_COMMENT :
`this is a
multi
line
comment`
Docs comments
Doc comments have at the beggining of comment the optinon [doc].
DOC_COMMENT:
`[doc] this is a documentation comment`