左递归文法造成无限递归 Parser Combinator本质上是一种自顶向下的Parser,因此在遇到左递归文法时会产生无限递归。举例如下: 简单的整数加减法文法: Expr: Expr'+'Expr | Expr'-'Expr | Num; Num: 整数; 实际代码: letpExpr, pExprRef=createParserForwardedToRef<int, unit>()
Parser combinators for ambiguous left-recursive grammars - FROST, HAFIZ, et al. () Citation Context ...priate to rely on Haskell’s least fixpoints. Otherwise, parsing libraries are restricted to top-down parsing algorithms, leftrecursion is difficult (although some algorithms deal with it ...
And so on. To avoid left recursion this can be rewritten (for example) as the following. Note that rewriting as follows also changes the operator associativity. value : <int> | <string> ; expr : <value> ('+' <expr>)* ; Avoiding left recursion can be tricky, but is easy once ...
And so on. To avoid left recursion this can be rewritten (for example) as the following. Note that rewriting as follows also changes the operator associativity. value : <int> | <string> ; expr : <value> ('+' <expr>)* ; Avoiding left recursion can be tricky, but is easy once ...
Parser combinators in Scala. Department of Computer Science, KU Leuven, Leuven, Belgium. 2008. 27. Burmako E. Scala macros: Let our powers combine!: On how rich syntax and static types work with metaprogramming. In: Proceedings of the 4th Workshop on Scala SCALA '13. New York: ACM; ...
http://fsharpforfunandprofit.com/posts/understanding-parser-combinators/个人不建议写xml解析，很费劲...
(a Java virtual machine programming language [23]), and the Open sourceparboiled2library [24] which we improved [25]. Theparboiled2library implements PEG in Scala. An alternative toparboiled2is the Scala combinators library [26]. We did not use it because it is slow and has memory ...
And so on. To avoid left recursion this can be rewritten (for example) as the following. Note that rewriting as follows also changes the operator associativity. value : <int> | <string> ; expr : <value> ('+' <expr>)* ; Avoiding left recursion can be tricky, but is easy once ...
Left recursionSome left-recursive grammars (e.g. left-associative operators) such asexpr ::= expr "-" term | term can be implemented using the chainl-combinator:public function expr() { return $this->chainl( $this->term, $this->char('-')->withResult(function ($left, $right) { ...
So again it looks for the first rule on the left. Which is expr again. And so on. To avoid left recursion this can be rewritten (for example) as the following. Note that rewriting as follows also changes the operator associativity. value : <int> | <string> ; expr : <value> ('+'...