forked from glen/fostr
62 lines
1.1 KiB
Plaintext
62 lines
1.1 KiB
Plaintext
module fostr
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imports
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Common
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context-free start-symbols
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Start
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lexical sorts
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STRING_LITERAL
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lexical syntax
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STRING_LITERAL = "'"~[\']*"'"
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context-free sorts
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Start LineSeq Line OptTermEx TermExLst TermEx Ex
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context-free syntax
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Start.TopLevel = LineSeq
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LineSeq = Line
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LineSeq.Sequence = sq:Line+ {layout(align-list sq)}
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Line = OptTermEx
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Line.ISequence = TermExLst OptTermEx {layout(0.first.line == 1.first.line)}
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TermExLst.Prior = TermEx+
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OptTermEx = ex:Ex {layout(offside ex)}
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OptTermEx = te:TermEx {layout(offside te)}
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TermEx.Terminate = <<Ex>;>
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Ex.Int = INT
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Ex.LitString = STRING_LITERAL
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Ex.EscString = STRING
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Ex.Stream = <stream>
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Ex.Sum = <<Ex> + <Ex>> {left}
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Ex.Gets = [[Ex] << [Ex]] {left}
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Ex.DefGets = [<<< [Ex]]
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Ex.To = [[Ex] >> [Ex]] {left}
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Ex.DefTo = [[Ex] >>>]
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Ex = <(<Ex>)> {bracket}
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context-free priorities
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Ex.To
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> Ex.DefTo
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> Ex.Sum
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> Ex.DefGets
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> Ex.Gets,
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// prevent cycle: no singletons
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LineSeq.Sequence <0> .> Line+ = Line
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