patternMinor
Bottom-Up Evaluation of Inherited Attributes
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bottomattributesevaluationinherited
Problem
I came across $2$ translation schemes of Syntax Directed Translation (SDT) in compilers which are as follows :
$L$-attributed definition based on a $LL(1)$ grammar.
$L$-attributed definition based on a $LL(1)$ grammar (each $LL(1)$ grammar
is also an $LR(1)$ grammar).
What these $2$ Definitions actually mean ? I am not getting ..
I am well aware of $L$-attributed definition and $S$-attributed definition of SDT and top down parsing and bottom up parsing but It is just that I am unable to recollect this information and phrase it according to the definitions given above.
It would be good, if I can get one example of both definitions so, that I can phrase it meaningfully of what is said .
- Using a top-down translation scheme, we can implement any
$L$-attributed definition based on a $LL(1)$ grammar.
- Using a bottom-up translation scheme, we can also implement any
$L$-attributed definition based on a $LL(1)$ grammar (each $LL(1)$ grammar
is also an $LR(1)$ grammar).
What these $2$ Definitions actually mean ? I am not getting ..
I am well aware of $L$-attributed definition and $S$-attributed definition of SDT and top down parsing and bottom up parsing but It is just that I am unable to recollect this information and phrase it according to the definitions given above.
It would be good, if I can get one example of both definitions so, that I can phrase it meaningfully of what is said .
Solution
- Using a top-down translation scheme, we can implement any $LL$-attributed definition based on $LL(1)$ grammar.
- Using a bottom-up translation scheme, we can also implement any $LL$-attributed definition based on $LL(1)$ grammar (each $LL(1)$ grammar is also an $LR(1)$ grammar). Using bottom-up translation scheme, we implement $LR$ grammar actually but since $LL(1) \subset LR(1)$ we can safely implement $LL(1)$ grammar as well.
Context
StackExchange Computer Science Q#67956, answer score: 3
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