83 lines
1.9 KiB
Ruby
83 lines
1.9 KiB
Ruby
module Vm
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class Expression
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# evey Expression has a eval function that returns a value
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def eval
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raise "abstract"
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end
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end
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class NumberExpression < Expression
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attr_reader :value
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def initialize val
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@value = val
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end
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def eval(context, builder)
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builder.mov "r0" , value
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end
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end
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class NameExpression < Expression
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attr_reader :name
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def initialize name
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@name = name
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end
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def eval(context, builder)
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param_names = context[:params] || []
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position = param_names.index(name)
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raise "Unknown parameter #{name}" unless position
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builder.iload position
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end
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end
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class FuncallExpression < Expression
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attr_reader :name, :args
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def initialize name, args
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@name , @args = name , args
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end
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def eval(context, builder)
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args.each { |a| a.eval(context, builder) }
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types = [builder.int] * (args.length + 1)
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builder.invokestatic builder.class_builder, name, types
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end
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end
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class ConditionalExpression < Expression
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attr_reader :cond, :if_true, :if_false
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def initialize cond, if_true, if_false
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@cond, @if_true, @if_false = cond, if_true, if_false
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end
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def eval(context, builder)
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cond.eval context, builder
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builder.ifeq :else
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if_true.eval context, builder
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builder.goto :endif
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builder.label :else
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if_false.eval context, builder
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builder.label :endif
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end
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end
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class FunctionExpression < Expression
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attr_reader :name, :params, :body
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def initialize name, params, body
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@name, @params, @body = name, params, body
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end
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def eval(context, builder)
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param_names = [params].flatten.map(&:name)
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context[:params] = param_names
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types = [builder.int] * (param_names.count + 1)
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builder.public_static_method(self.name, [], *types) do |method|
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self.body.eval(context, method)
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method.ireturn
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end
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end
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end
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end
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