similar to: Support for user defined unary functions

Gabe, The unary functions have the same precedence as normal SPECIALS (although the new unary forms take precedence over binary SPECIALS). So they are lower precedence than unary + and -. Yes, both of your examples are valid with this patch, here are the results and quoted forms to see the precedence. `%chr%` <- function(x) as.character(x) `%identical%` <- function(x, y)

Martin, Jim can speak directly to his motivations; I don't claim to be able to do so. That said, I suspect this is related to a conversation on twitter about wanting an infix "unquote" operator in the context of the non-standard evaluation framework Hadley Wickham and Lionel Henry (and possibly others) are working on. They're currently using !!! and !! for things related to

I guess this would establish a separate "namespace" of symbolic prefix operators, %*% being an example in the infix case. So you could have stuff like %?%, but for non-symbolic (spelled out stuff like %foo%), it's hard to see the advantage vs. foo(x). Those examples you mention should probably be addressed (eventually) in the core language, and it looks like people are already able

I agree there is no reason they _need_ to be the same precedence, but I think SPECIALS are already have the proper precedence for both unary and binary calls. Namely higher than all the binary operators (except for `:`), but lower than the other unary operators. Even if we gave unary specials their own precedence I think it would end up in the same place. `%l%` <- function(x) tail(x, n =

>After off list discussions with Jonathan Carrol and with >Michael Lawrence I think it's doable, unambiguous, >and even imo pretty intuitive for an "unquote" operator. For those of us who are not CS/Lisp mavens, what is an "unquote" operator? Can you expression quoting and unquoting in R syntax and show a few examples where is is useful, intuitive, and fits in to

The unquoting discussion is IMHO separate from this proposal and as you noted probably better served by a native operator with different precedence. I think the main benefit to providing user defined prefix operators is it allows package authors to experiment with operator ideas and gauge community interest. The current situation means any novel unary semantics either need to co-opt existing

Your example x = 5 exp = parse(text="f(uq(x)) + y +z") # expression: f(uq(x)) +y + z do_unquote(expr) # -> the language object f(5) + y + z could be done with the following wrapper for bquote my_do_unquote <- function(language, envir = parent.frame()) { if (is.expression(language)) { # bquote does not go into expressions, only calls

Jim, This seems cool. Thanks for proposing it. To be concrete, he user-defined unary operations would be of the same precedence (or just slightly below?) built-in unary ones? So "100" %identical% %chr% 100 would work and return TRUE under your patch? And with %num% <- as.numeric, then 1 + - %num% "5" would also be legal (though quite ugly imo) and work? Best, ~G On

I don't have a positive or negative opinion on this yet, but I do have a question. If I define both unary and binary operators with the same name (in different frames, presumably), what would happen? Is "a %chr% b" a syntax error if unary %chr% is found first? If both might be found, does "a %chr% %chr% b" mean "%chr%(a, %chr% b)", or is it a syntax error

>>>>> Jim Hester <james.f.hester at gmail.com> >>>>> on Thu, 16 Mar 2017 12:31:56 -0400 writes: > Gabe, > The unary functions have the same precedence as normal SPECIALS > (although the new unary forms take precedence over binary SPECIALS). > So they are lower precedence than unary + and -. Yes, both of your > examples are

I used the `function(x)` form to explicitly show the function was being called with only one argument, clearly performance implications are not relevant for these examples. I think of this mainly as a gap in the tooling we provide users and package authors. R has native prefix `+1`, functional `f(1)` and infix `1 + 1` operators, but we only provide a mechanism to create user defined functional

I am biased against introducing new syntax, but if one is experimenting with it one should make sure the precedence feels right. I think the unary and binary minus-sign operators have different precedences so I see no a priori reason to make the unary and binary %xxx% operators to be the same. Bill Dunlap TIBCO Software wdunlap tibco.com On Thu, Mar 16, 2017 at 3:18 PM, Michael Lawrence

Jim, One more note about precedence. It prevents a solution like the one you proposed from solving all of the problems you cited. By my reckoning, a "What comes next is for NSE" unary operator needs an extremely low precedence, because it needs to greedily grab "everything" (or a large amount) that comes after it. Normal-style unary operators, on the other hand, explicitly

William, Unbeknownst to me when I sent this, Jonathon Carrol started a specific thread about unquoting and a proposal for supporting it at the language level, which I think is a better place to discuss unquoting specifically. That said, the basics as I understand them in the context of non-standard evaluation, unquoting (or perhaps interpolation) is essentially substituting part of an unevaluated

Bill, Right. My example was the functional form for clarity. There is a desire for a unary-operator form. (rlang's !! and !!! operators described in the comments in the file I linked to). I can't really make that argument because I'm not one of the people who wanted that. You'd have to talk to the authors of the rlang package to find out their reasons for thinking that is

Hi folks I am using the lmer function (in the lme4 library) to analyse some data where individuals are clustered into sets (using the SetID variable) with a single fixed effect (cc - 0 or 1). The lmer model and output is shown below. Whilst the fixed effects are consistent with stata (using xtmixed, see below), the std dev of the random effect for SetID is very very small (3.5803e-05)compared to

Hello I was reading the source main/src/gram.y and had one question, how does R parse x = 1 According the grammar: prog : END_OF_INPUT { return 0; } | '\n' { return xxvalue(NULL,2,NULL); } | expr_or_assign '\n' { return xxvalue($1,3,&@1); } | expr_or_assign ';' { return xxvalue($1,4,&@1); } | error { YYABORT; } ; So this should be of the 3rd

The documentation (help("Syntax")) gives the operator precedence of the assignment operators and help, from highest to lowest, as: ?<- <<-? assignment (right to left) ?=? assignment (right to left) ??? help (unary and binary) If I understand correctly this implies that `a = b ? c` and `a <- b ? c` should parse

Hello, Is there a way to define a custom unary operator in R (other than making a class and 'overloading' the normal unary operators in R)? The documentation seems to suggest that only custom binary operators are possible with the ``%abc%``construct but I was wondering whether any one has done so. None of the RSiteSearch or RSeek queries I posed suggested that this question had

Hi llvmdev, I've noticed that there is no unary operator in LLVM. For unary operator such as Neg or Or operator, the IR builder just creates a binary operation with one dummy operand, 01823 <http://llvm.org/doxygen/classllvm_1_1BinaryOperator.html#a073c092ce74a122e898e435e60e84599> BinaryOperator <http://llvm.org/doxygen/classllvm_1_1BinaryOperator.html>