[Rd] Suggested Patch: Library returns matching installed packages when typo present

[Marcel Ramos]

Dear R-core devs,

I hope this email finds you well.

Please see the proposed patch to R-devel below:

Scenario:

When loading a package using `library`, a package may not be found if the cases are not matching:

```
> library(ORG.Hs.eg.db)
 Error in library(ORG.Hs.eg.db) :
  there is no package called 'ORG.Hs.eg.db'
```


Suggested Patch:

Returns a message matching what `install.packages` returns in such situations:

```
> library("ORG.Hs.eg.db")
 Error in library("ORG.Hs.eg.db") :
   there is no package called 'ORG.Hs.eg.db'
 In addition: Warning message:
 Perhaps you meant 'org.Hs.eg.db' ?
```

This patch will be helpful with 'fat-finger' typos. It will match a package
called with `library` against installed packages.


svn diff:

Index: src/library/base/R/library.R
===================================================================
--- src/library/base/R/library.R    (revision 76727)
+++ src/library/base/R/library.R    (working copy)
@@ -300,8 +300,13 @@
         pkgpath <- find.package(package, lib.loc, quiet = TRUE,
                                     verbose = verbose)
             if(length(pkgpath) == 0L) {
-                if(length(lib.loc) && !logical.return)
+                if(length(lib.loc) && !logical.return) {
+                    allpkgs <- .packages(TRUE, lib.loc)
+                    if (!is.na(w <- match(tolower(package), tolower(allpkgs))))
+                        warning(sprintf("Perhaps you meant %s ?",
+                            sQuote(allpkgs[w])), call. = FALSE, domain = NA)
                     stop(packageNotFoundError(package, lib.loc, sys.call()))
+                }
                 txt <- if(length(lib.loc))
                     gettextf("there is no package called %s", sQuote(package))
                 else


Thank you!

Best regards,

Marcel



--
Marcel Ramos
Bioconductor Core Team
Roswell Park Comprehensive Care Center
Dept. of Biostatistics & Bioinformatics
Elm & Carlton Streets
Buffalo, New York 14263


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