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Annotation of 43BSD/contrib/icon/src/cmd/csgen.icn, revision 1.1

1.1     ! root        1: #      CSGEN(1)
        !             2: #
        !             3: #      Generate instances of sentences defined by context-sensitive
        !             4: #      grammars
        !             5: #
        !             6: #      Ralph E. Griswold
        !             7: #
        !             8: #      Last modified 4/27/83
        !             9: #
        !            10: 
        !            11: global xlist
        !            12: 
        !            13: procedure main(x)
        !            14:    local line, goal, count, s
        !            15:    while line := read() do             #  read in grammar
        !            16:       if xpairs(line) then next
        !            17:       else {
        !            18:          line ? (goal := move(1),move(1),count := (0 < integer(tab(0))))
        !            19:          break
        !            20:          }
        !            21:    every 1 to count do {               #  generate sentences
        !            22:       s := goal
        !            23:       while upto(&ucase,s) do {                #  test for nonterminal
        !            24:          if x[1] == "-t" then write(&errout,s)
        !            25:                                        #  quit on deadlock
        !            26:          if not(s ? replace(!xlist)) then break next
        !            27:          until s ?:= replace(?xlist)   #  make replacement
        !            28:          }
        !            29:       write(s)
        !            30:       }
        !            31: end
        !            32: 
        !            33: #  replace left hand side by right hand side
        !            34: #
        !            35: procedure replace(a)
        !            36:    suspend tab(find(a[1])) || (move(*a[1]),a[2]) || tab(0)
        !            37: end
        !            38: 
        !            39: #  enter rewriting rule
        !            40: #
        !            41: procedure xpairs(s)
        !            42:    local i, a
        !            43:    initial xlist := []
        !            44:    if s ? {
        !            45:                                #  handle optional replication factor
        !            46:       i := 1(0 < integer(tab(upto(':'))),move(1)) | 1 &
        !            47:       a := [tab(find("->")),(move(2),tab(0))]
        !            48:       }
        !            49:    then {
        !            50:       every 1 to i do put(xlist,a)
        !            51:       return
        !            52:       }
        !            53: end

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