21 lines
510 B
Plaintext
21 lines
510 B
Plaintext
tree grammar Reduce;
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options
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{
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tokenVocab=VecMath;
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ASTLabelType=CommonTree;
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output=AST;
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filter=true;
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language=CSharp3;
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}
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@namespace{Antlr3.Runtime.Test.Composition}
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/** Rewrite: x+x to be 2*x, 2*x to be x<<1, x<<n<<m to be x<<(n+m) */
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bottomup
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: ^(PLUS i=INT j=INT {$i.int==$j.int}?) -> ^(MULT["*"] INT["2"] $j)
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| ^(MULT x=INT {$x.int==2}? y=.) -> ^(SHIFT["<<"] $y INT["1"])
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| ^(SHIFT ^(SHIFT e=. n=INT) m=INT)
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-> ^(SHIFT["<<"] $e INT[($n.int+$m.int).ToString()])
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;
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