Talk:Compiler/Verifying syntax: Difference between revisions
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:First/left one yes, second/right one no. Consider expr_level_4 = ["not"] expr_level_5 [('=' | '<') ["not"] expr_level_5] ; |
:First/left one yes, second/right one no. Consider expr_level_4 = ["not"] expr_level_5 [('=' | '<') ["not"] expr_level_5] ; |
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:Ideally the not would be moved into its own private rule, rather than clog up the (partial) comparison rule anyway. --[[User:Petelomax|Pete Lomax]] ([[User talk:Petelomax|talk]]) 19:31, 3 January 2020 (UTC) |
:Ideally the not would be moved into its own private rule, rather than clog up the (partial) comparison rule anyway. --[[User:Petelomax|Pete Lomax]] ([[User talk:Petelomax|talk]]) 19:31, 3 January 2020 (UTC) |
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Note the square brackets [] around the [('=' | '<') expr_level_5]. This means that the expression |
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'2 < 3 < 4' |
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should not be legal (i.e. a non-associative violation). |
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[] means 0 or 1. |
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{} means 0 or more. |
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