Glen Whitney
804a00902a
Caveat: type is still not being assigned for the Sequence() constructor. Also fixes the parsing of literal strings (whitespace just after the opening quote was being ignored, and was ambiguous just before the opening quote).
56 lines
1 KiB
Text
56 lines
1 KiB
Text
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.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.To = [[Ex] >> [Ex]] {left}
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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.Sum
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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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