在R包中定义组通用函数

Question

我在写一个R包时定义了一个通用组函数时遇到了问题。

这是一个相当小的例子：

setGroupGeneric('FooBarFunctions', function(x, y) NULL) 

setGeneric('foo', group = 'FooBarFunctions', function(x, y) standardGeneric('foo')) 
setGeneric('bar', group = 'FooBarFunctions', function(x, y) standardGeneric('bar')) 

setMethod('foo', signature(x = 'ANY', y = 'ANY'), 
function(x, y) 
    cat(sprintf('foo,ANY (%s),ANY (%s)\n', x, y))) 

setMethod('bar', signature(x = 'ANY', y = 'ANY'), 
function(x, y) 
    cat(sprintf('bar,ANY (%s),ANY (%s)\n', x, y))) 

setMethod('FooBarFunctions', signature(x = 'character', y = 'ANY'), 
function(x, y) 
    cat(sprintf('FooBarFunctions,character (%s),ANY (%s)\n', x, y))) 

如果我将此代码粘贴到R端子，然后一切按预期工作：

> foo(1, 2) 
foo,ANY (1),ANY (2) 
> bar(1, 2) 
bar,ANY (1),ANY (2) 
> foo('a', 2) 
FooBarFunctions,character (a),ANY (2) 
> bar('a', 2) 
FooBarFunctions,character (a),ANY (2) 

然而，当我尝试建立这变成了一个包，我遇到了以下错误：

$ R CMD INSTALL . 
* installing to library ‘~/R/x86_64-pc-linux-gnu-library/2.15’ 
* installing *source* package ‘anRpackage’ ... 
** R 
** preparing package for lazy loading 
** help 
No man pages found in package ‘anRpackage’ 
*** installing help indices 
** building package indices 
** testing if installed package can be loaded 
**Error in .setupMethodsTables(generic) : 
    trying to get slot "group" from an object of a basic class ("NULL") with no slots** 
Error: loading failed 
Execution halted 
ERROR: loading failed 
* removing ‘~/R/x86_64-pc-linux-gnu-library/2.15/anRpackage’ 

我使用packag的默认输出已增加e.skeleton（）：

exportPattern("^[[:alpha:]]+") 

进入空间文件

任何想法，我做错了吗？

Answer 1

我可以得到这个工作，如果我加载运行的代码。这里的关键是evalqOnLoad呼叫

evalqOnLoad({ 

    setGroupGeneric('FooBarFunctions', function(x, y) NULL) 

    setGeneric('foo', group = 'FooBarFunctions', function(x, y) standardGeneric('foo')) 
    setGeneric('bar', group = 'FooBarFunctions', function(x, y) standardGeneric('bar')) 

    setMethod('foo', signature(x = 'ANY', y = 'ANY'), 
    function(x, y) 
     cat(sprintf('foo,ANY (%s),ANY (%s)\n', x, y))) 

    setMethod('bar', signature(x = 'ANY', y = 'ANY'), 
    function(x, y) 
     cat(sprintf('bar,ANY (%s),ANY (%s)\n', x, y))) 

    setMethod('FooBarFunctions', signature(x = 'character', y = 'ANY'), 
    function(x, y) 
     cat(sprintf('FooBarFunctions,character (%s),ANY (%s)\n', x, y))) 

}) 

包中的“喇嘛”

：

> require(bla) 
Le chargement a nécessité le package : bla 
> foo(1, 2) 
foo,ANY (1),ANY (2) 
> bar(1, 2) 
bar,ANY (1),ANY (2) 
> foo("a", 2) 
FooBarFunctions,character (a),ANY (2) 
> bar("a", 2) 
FooBarFunctions,character (a),ANY (2)