51 lines
1.4 KiB
Ruby
51 lines
1.4 KiB
Ruby
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module Vm
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class Parser < Parslet::Parser
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rule(:name) { match('[a-z]').repeat(1).as(:name) >> space? }
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rule(:number) { match('[0-9]').repeat(1).as(:number) >> space? }
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rule(:space) { match('\s').repeat(1) }
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rule(:space?) { space.maybe }
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rule(:args) {
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lparen >>
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((expression.as(:arg) >> (comma >> expression.as(:arg)).repeat(0)).maybe).as(:args) >>
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rparen
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}
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rule(:funcall) { name.as(:funcall) >> args }
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rule(:expression) { cond | funcall | number | name }
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rule(:lparen) { str('(') >> space? }
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rule(:rparen) { str(')') >> space? }
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rule(:comma) { str(',') >> space? }
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rule(:cond) {
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if_kw >> lparen >> expression.as(:cond) >> rparen >>
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body.as(:if_true) >>
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else_kw >>
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body.as(:if_false)
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}
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rule(:body) { lbrace >> expression.as(:body) >> rbrace }
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rule(:lbrace) { str('{') >> space? }
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rule(:rbrace) { str('}') >> space? }
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rule(:comma) { str(',') >> space? }
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rule(:if_kw) { str('if') >> space? }
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rule(:else_kw) { str('else') >> space? }
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rule(:func) {
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func_kw >> name.as(:func) >> params >> body
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}
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rule(:func_kw) { str('function') >> space? }
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rule(:params) {
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lparen >>
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((name.as(:param) >> (comma >> name.as(:param)).repeat(0)).maybe).as(:params) >>
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rparen
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}
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rule(:root){ func.repeat(0) >> expression | expression | args }
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end
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end
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