fostr/syntax/fostr.sdf3

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