60 lines
2.5 KiB
Ruby
60 lines
2.5 KiB
Ruby
require 'parslet'
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require 'ast/expression'
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module Parser
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class Transform < Parslet::Transform
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rule(:string => sequence(:chars)) { Ast::StringExpression.new chars.join }
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rule(:esc => simple(:esc)) { '\\' + esc }
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rule(char: simple(:char)) { char }
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rule(:integer => simple(:value)) { Ast::IntegerExpression.new(value.to_i) }
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rule(:name => simple(:name)) { Ast::NameExpression.new(name.to_s) }
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rule(:argument => simple(:argument)) { argument }
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rule(:argument_list => sequence(:argument_list)) { argument_list }
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# need TWO transform rules, for one/many arguments (see the[] wrapping in the first)
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rule(:function_call => simple(:function_call),
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:argument_list => simple(:argument)) do
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Ast::FuncallExpression.new(function_call.name, [argument])
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end
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rule( :function_call => simple(:function_call),
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:argument_list => sequence(:argument_list)) do
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Ast::FuncallExpression.new(function_call.name, argument_list)
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end
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rule(:conditional => simple(:conditional),
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:if_true => {:expressions => sequence(:if_true)},
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:if_false => {:expressions => sequence(:if_false)}) do
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Ast::ConditionalExpression.new(conditional, if_true, if_false)
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end
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rule(:parmeter => simple(:parmeter)) { parmeter }
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rule(:parmeter_list => sequence(:parmeter_list)) { parmeter_list }
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# need TWO transform rules, for one/many arguments (see the[] wrapping in the first)
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rule(:function_definition => simple(:function_definition),
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:parmeter_list => simple(:parmeter),
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:expressions => sequence(:expressions)) do
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Ast::FunctionExpression.new(function_definition.name, [parmeter], expressions)
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end
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rule(:function_definition => simple(:function_definition),
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:parmeter_list => sequence(:parmeter_list),
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:expressions => sequence(:expressions)) do
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Ast::FunctionExpression.new(function_definition.name, parmeter_list, expressions)
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end
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rule(:asignee => simple(:left) , :asigned => simple(:right) ) do
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Ast::AssignmentExpression.new(left.name, right )
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end
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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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