52 lines
1.5 KiB
Ruby
52 lines
1.5 KiB
Ruby
module Ast
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class WhileExpression < Expression
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# attr_reader :condition, :body
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def compile method , message
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start = Virtual::Label.new("while_start")
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method.add start
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is = condition.compile(method,message)
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branch = Virtual::ImplicitBranch.new "while"
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merge = Virtual::Label.new(branch.name)
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branch.other = merge #false jumps to end of while
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method.add branch
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last = is
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body.each do |part|
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last = part.compile(method,message )
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raise part.inspect if last.nil?
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end
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# unconditionally brnach to the start
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merge.next = method.current.next
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method.current.next = start
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# here we add the end of while that the branch jumps to
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#but don't link it in (not using add)
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method.current = merge
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last
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end
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def old
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into = context.function
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ret = into.new_block "while_end"
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while_block = into.new_block "while_start"
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into.insert_at while_block
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puts "compiling while condition #{condition}"
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cond_val = condition.compile(context)
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into.b ret , condition_code: cond_val.not_operator
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into.insertion_point.branch = ret
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last = nil
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body.each do |part|
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puts "compiling in while #{part}"
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last = part.compile(context)
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end
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into.b while_block
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into.insertion_point.branch = while_block
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puts "compile while end"
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into.insert_at ret
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return last
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end
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end
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end |