diff options
Diffstat (limited to 'doc/guix.texi')
| -rw-r--r-- | doc/guix.texi | 31 |
1 files changed, 16 insertions, 15 deletions
diff --git a/doc/guix.texi b/doc/guix.texi index 3c72e6596e..18e6733083 100644 --- a/doc/guix.texi +++ b/doc/guix.texi @@ -2490,13 +2490,9 @@ Gexps are meant to be written to a file and run or manipulated by other processes. @item -When a package or derivation is unquoted inside a gexp, the result is as -if its output file name had been introduced. - -Actually this mechanism is not limited to package and derivation -objects; @dfn{compilers} able to ``lower'' other high-level objects to -derivations can be defined, such that these objects can also be inserted -into gexps. +When a high-level object such as a package or derivation is unquoted +inside a gexp, the result is as if its output file name had been +introduced. @item Gexps carry information about the packages or derivations they refer to, @@ -2504,6 +2500,11 @@ and these dependencies are automatically added as inputs to the build processes that use them. @end itemize +Actually this mechanism is not limited to package and derivation +objects; @dfn{compilers} able to ``lower'' other high-level objects to +derivations can be defined, such that these objects can also be inserted +into gexps. + To illustrate the idea, here is an example of a gexp: @example @@ -2563,24 +2564,24 @@ or more of the following forms: @table @code @item #$@var{obj} @itemx (ungexp @var{obj}) -Introduce a reference to @var{obj}. @var{obj} may be a package or a +Introduce a reference to @var{obj}. @var{obj} may have one of the +supported types, for example a package or a derivation, in which case the @code{ungexp} form is replaced by its output file name---e.g., @code{"/gnu/store/@dots{}-coreutils-8.22}. -If @var{obj} is a list, it is traversed and any package or derivation -references are substituted similarly. +If @var{obj} is a list, it is traversed and references to supported +objects are substituted similarly. If @var{obj} is another gexp, its contents are inserted and its dependencies are added to those of the containing gexp. If @var{obj} is another kind of object, it is inserted as is. -@item #$@var{package-or-derivation}:@var{output} -@itemx (ungexp @var{package-or-derivation} @var{output}) +@item #$@var{obj}:@var{output} +@itemx (ungexp @var{obj} @var{output}) This is like the form above, but referring explicitly to the -@var{output} of @var{package-or-derivation}---this is useful when -@var{package-or-derivation} produces multiple outputs (@pxref{Packages -with Multiple Outputs}). +@var{output} of @var{obj}---this is useful when @var{obj} produces +multiple outputs (@pxref{Packages with Multiple Outputs}). @item #+@var{obj} @itemx #+@var{obj}:output |