42 lines
1.5 KiB
Ruby
42 lines
1.5 KiB
Ruby
require 'parslet'
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require 'vm/nodes'
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module Parser
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class Transform < Parslet::Transform
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rule(:number => simple(:value)) { Vm::NumberExpression.new(value.to_i) }
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rule(:name => simple(:name)) { Vm::NameExpression.new(name.to_s) }
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rule(:arg => simple(:arg)) { arg }
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rule(:args => sequence(:args)) { args }
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rule(:funcall => simple(:funcall),
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:args => simple(:args)) { Vm::FuncallExpression.new(funcall.name, [args]) }
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rule(:funcall => simple(:funcall),
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:args => sequence(:args)) { Vm::FuncallExpression.new(funcall.name, args) }
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rule(:cond => simple(:cond),
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:if_true => {:body => simple(:if_true)},
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:if_false => {:body => simple(:if_false)}) { Vm::ConditionalExpression.new(cond, if_true, if_false) }
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rule(:param => simple(:param)) { param }
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rule(:params => sequence(:params)) { params }
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rule(:func => simple(:func),
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:params => simple(:name),
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:body => simple(:body)) { Vm::FunctionExpression.new(func.name, [name], body) }
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rule(:func => simple(:func),
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:params => sequence(:params),
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:body => simple(:body)) { Vm::FunctionExpression.new(func.name, params, body) }
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#shortcut to get the ast tree for a given string
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# optional second arguement specifies a rule that will be parsed (mainly for testing)
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def self.ast string , rule = :root
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syntax = Parser.new.send(rule).parse(string)
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tree = Transform.new.apply(syntax)
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tree
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end
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end
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end
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