46 lines
1.3 KiB
Ruby
46 lines
1.3 KiB
Ruby
require_relative "basic_types"
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require_relative "tokens"
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require_relative "keywords"
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module Parser
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#obviously a work in progress !!
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# We "compose" the parser from bits, divide and hopefully conquer
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class Composed < Parslet::Parser
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include BasicTypes
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include Tokens
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include Keywords
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rule(:argument_list) {
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left_parenthesis >>
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((expression.as(:argument) >> (comma >> expression.as(:argument)).repeat(0)).maybe).as(:argument_list) >>
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right_parenthesis
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}
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rule(:function_call) { name.as(:function_call) >> argument_list }
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rule(:expression) { conditional | function_call | integer | name }
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rule(:conditional) {
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keyword_if >> left_parenthesis >> expression.as(:conditional) >> right_parenthesis >>
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block.as(:if_true) >>
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keyword_else >>
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block.as(:if_false)
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}
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rule(:block) { left_brace >> expression.as(:block) >> right_brace }
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rule(:function_definition) {
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keyword_def >> name.as(:function_definition) >> parmeter_list >> block
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}
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rule(:parmeter_list) {
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left_parenthesis >>
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((name.as(:parmeter) >> (comma >> name.as(:parmeter)).repeat(0)).maybe).as(:parmeter_list) >>
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right_parenthesis
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}
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rule(:root){ function_definition.repeat(0) >> expression | expression | argument_list }
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end
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end
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