Distribution.Client.CmdErrorMessages

Singular for singleton lists and plural otherwise.

The optional stanza type (test suite or benchmark), if it is one.

Used to render a singular or plural version of something

plural (listPlural theThings) "it is" "they are"

Render a list of things in the style foo, bar and baz

Render a list of things in the style blah blah; this that; and the other

Default implementation of renderTargetProblem.

Several commands have a TargetProblemNoTargets problem constructor. This renders an error message for those cases.

Several commands have a TargetProblemNoneEnabled problem constructor. This renders an error message for those cases.

Default implementation of reportTargetProblems simply renders one problem per line.

When rendering lists of things it often reads better to group related things, e.g. grouping components by package name

renderListSemiAnd
  [     "the package " ++ prettyShow pkgname ++ " components "
     ++ renderListCommaAnd showComponentName components
  | (pkgname, components) <- sortGroupOn packageName allcomponents ]

Does the TargetSelector potentially refer to one package or many?

Does the TargetSelector refer to packages or to components?

A tag used in rendering messages to distinguish singular or plural.

Either the component as a whole or detail about a file or module target within a component.

A target selector is an expression selecting a set of components (as targets for actions like build, run, test etc). A target selector corresponds to the user syntax for referring to targets on the command line.

From the users point of view a target can be many things: packages, dirs, component names, files etc. Internally we consider a target to be a specific component (or module/file within a component), and all the users' notions of targets are just different ways of referring to these component targets.

So target selectors are expressions in the sense that they are interpreted to refer to one or more components. For example a TargetPackage gets interpreted differently by different commands to refer to all or a subset of components within the package.

The syntax has lots of optional parts:

[ package name | package dir | package .cabal file ]
[ [lib:|exe:] component name ]
[ module name | source file ]