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34 lines
894 B
34 lines
894 B
module Lox
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class AstPrinter
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def print(expr) = expr.accept(self)
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def visit_binary(expr) = parenthesize(expr.op.lexeme, expr.left, expr.right)
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def visit_grouping(expr) = parenthesize("group", expr.expr)
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def visit_literal(expr) = expr.value&.to_s || "nil"
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def visit_unary(expr) = parenthesize(expr.op.lexeme, expr.right)
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def visit_print(expr) = parenthesize("print", expr.expr)
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def visit_var(expr)
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exprs = [expr.initializer].reject(&:nil?)
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parenthesize("var #{expr.name.lexeme}", *exprs)
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end
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def visit_variable(expr)
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"(var #{expr.name.lexeme})"
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end
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def visit_assign(expr)
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parenthesize("assign #{expr.name.lexeme}", expr.value)
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end
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private
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def parenthesize(name, *exprs)
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inside = [name]
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inside.concat(exprs.map {|expr| expr.accept(self) })
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"(#{inside.join(" ")})"
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end
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end
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end
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