context-free-grammar

Or, to be a little more precise: which programming languages are defined by a context-free grammar? From what I gather C++ is not context-free due to things like macros and templates. My gut tells me that functional languages might be context free, but I don't have any hard data to back that up with. Extra rep for concise examples :-) The set of programs that are syntactically correct is context-free for almost all languages. The set of programs that compile is not context-free for almost all languages. For example, if the set of all compiling C programs were context free, then by intersecting

Can someone explain to me what a context free grammar is? After looking at the Wikipedia entry and then the Wikipedia entry on formal grammar, I am left utterly and totally befuddled. Would someone be so kind as to explain what these things are? I am wondering this because I wish to investigate parsing, and also on the side, the limitation of a regex engine. I'm not sure if these terms are directly programming related, or if they are related more to linguistics in general. If that is the case, I apologize, perhaps this could be moved if so? aegrisomnia A context free grammar is a grammar which

Many productions in EcmaScript are given with the following "modifiers": [Yield, Await, In, Return] Here are a few examples: ArrayLiteral[Yield, Await]: ... ElementList[Yield, Await]: ... AssignmentExpression[+In, ?Yield, ?Await] I've searched through the spec for the explanation, specifically Grammar Notation section, but can't find it. It should be there. Can someone please point me to the relevant paragraph and maybe provide a short explanation? Section 5.1.5: Grammar Notation - A production may be parameterized by a subscripted annotation of the form “[parameters]”, which may appear as a

I'm trying to get my head around context free grammars and I think I'm close. What is baffling me is this one question (I'm doing practise questions as I have an exam in a month's time): I've come up with this language but I believe it's wrong. S --> aSb | A | B A --> aA | Σ B --> bB | Σ Apparently this is the correct solution: S --> aSb | aA | bB A --> aA | Σ B --> bB | Σ What I don't quite understand is why we have S --> aSb | aA | bB and not just S --> aSb | A | B . What is the need for the terminals? Can't I just call A instead and grab my terminals that way? Testing to see if I can

E -> E+T | E-T | T T -> T*F | T/F | F F -> i | (E) How can I modify this grammar to allow an exponentiation operation ^ so that I can write i+i^i*i ? Since we know that order of operations is higher for ^ then all I know is that I must make it right associative. In EBNF ( Extended Backus-Naur Form ), this could look as follows: expr -> term [ ('+' | '-') term ]* term -> factor [ ('*' | '/') factor ]* factor -> base [ '^' exponent ]* base -> '(' expr ')' | identifier | number exponent -> '(' expr ')' | identifier | number (taken from here ) Translated to your notation (no distinction between

I often hear claims that C++ is a context-sensitive language. Take the following example: a b(c); Is this a variable definition or a function declaration? That depends on the meaning of the symbol c . If c is a variable , then a b(c); defines a variable named b of type a . It is directly initialized with c . But if c is a type , then a b(c); declares a function named b that takes a c and returns an a . If you look up the definition of context-free languages, it will basically tell you that all grammar rules must have left-hand sides that consist of exactly one non-terminal symbol. Context