Copy BQL.g to BQL.g4 and enable antlr4-maven-plugin
Fix declared grammar name
Remove unnecessary options
Use new tokens{} syntax
Remove unnecessary package clauses
Remove unnecessary rulecatch block (use BailErrorStrategy instead)
Move lexer rules to end of grammar
Remove unsupported rewrite syntax and AST operators
Remove syntactic predicates (unnecessary and unsupported in ANTLR 4)
Use the channel lexer command
Use locals[] instead of scope{}
Fix constructor name and invalid escape sequence
Create lexer rules for implicitly defined tokens
Use non-greedy matching in lexer rule
Semantic predicates do not need to be explicitly gated in ANTLR 4
Remove unsupported option k=3
Move semantic checks for select_stmt out of grammar
Move select_stmt action code to listener
Move statement action code to listener
Move selection_list action code to listener