61 lines
2.5 KiB
Ruby
61 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(:array => sequence(:array) ) { Ast::ArrayExpression.new(array) }
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rule(:element => simple(:element)) { element }
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rule(:hash => sequence(:hash) ) { Ast::HashExpression.new(hash) }
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rule(:argument => simple(:argument) , :element => simple(:element)) { Ast::AssociationExpression.new(argument,element) }
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rule(:hash_pair => simple(:hash_pair) ) { hash_pair }
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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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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(:if => simple(:if), :conditional => simple(:conditional),
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:if_true => {:expressions => sequence(:if_true) , :else => simple(:else) },
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:if_false => {:expressions => sequence(:if_false) , :end => simple(:e) }) do
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Ast::ConditionalExpression.new(conditional, if_true, if_false)
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end
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rule(:while => simple(:while),
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:while_cond => simple(:while_cond) , :do => simple(:do) ,
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:body => {:expressions => sequence(:body) , :end => simple(:e) }) do
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Ast::WhileExpression.new(while_cond, body)
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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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rule(:function_name => simple(:function_name),
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:parmeter_list => sequence(:parmeter_list),
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:expressions => sequence(:expressions) , :end => simple(:e)) do
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Ast::FunctionExpression.new(function_name.name, parmeter_list, expressions)
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end
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rule(l: simple(:l), o: simple(:o) , r: simple(:r)) do
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Ast::OperatorExpression.new( o.to_s.strip , l ,r)
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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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