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module Lox
class AstPrinter
def print(expr) = expr.accept(self)
def visit_binary(expr) = parenthesize(expr.op.lexeme, expr.left, expr.right)
def visit_grouping(expr) = parenthesize("group", expr.expr)
def visit_literal(expr) = expr.value&.to_s || "nil"
def visit_unary(expr) = parenthesize(expr.op.lexeme, expr.right)
def visit_print(expr) = parenthesize("print", expr.expr)
def visit_var(expr)
exprs = [expr.initializer].reject(&:nil?)
parenthesize("var #{expr.name.lexeme}", *exprs)
end
def visit_variable(expr)
"(var #{expr.name.lexeme})"
end
def visit_assign(expr)
parenthesize("assign #{expr.name.lexeme}", expr.value)
end
def visit_block(expr)
parenthesize("block", *expr.stmts)
end
def visit_if(stmt)
exprs = [stmt.cond, stmt.then]
exprs << stmt.else if stmt.else
parenthesize("if", *exprs)
end
def visit_expr(expr)
expr.expr.accept(self)
end
def visit_call(call)
parenthesize(call.callee.accept(self), *call.args)
end
private
def parenthesize(name, *exprs)
inside = [name]
inside.concat(exprs.map {|expr| expr.accept(self) })
"(#{inside.join(" ")})"
end
end
end