Questions on Nim's grammar

[lyhokia]

Q1 is solved, I scan through nim's compiler/parser.nim and found these comments:
    
    
    #| castExpr = 'cast' ('[' optInd typeDesc optPar ']' '(' optInd expr optPar 
')') /
      #                    ('(' optInd exprColonEqExpr optPar ')')
    
    
    Run

Thus this should be a typo.