Changes between Version 23 and Version 24 of Commentary/Packages/GhcPackagesProposal

Timestamp:

07/06/06 15:49:00 (7 years ago)

Author:

brianh@…

Comment:

typo + section on EBNF rule for import directive

Commentary/Packages/GhcPackagesProposal

@@ -153 +153 @@
 }}}
 
-It is clear from the above examples that they keyword {{{from}}} is redundant - the presence of a string literal after the keyword {{{import}}} is sufficient to distinguish per-package imports from the ordinary shared-namespace imports, so the above could instead be written as
+It is clear from the above examples that the keyword {{{from}}} is redundant - the presence of a string literal (or special keyword to denote the home package) after the keyword {{{import}}} is sufficient to distinguish per-package imports from the ordinary shared-namespace imports, so the above could instead be written as
 {{{
     import "base"
@@ -167 +167 @@
 }}}
 
+=== Syntax formalised and summarised ===
 
+A possible syntax which covers everything in this proposal is therefore:
+
+   '''import''' [''package-name''] '''{''' ''import-specifier'' [''';''' ''import-specifier''] '''}'''
+
+where ''package-name'' is a string literal or the keyword {{{home}}}, the ''import-specifier'' corresponds to everything that is currently allowed after the keyword {{{import}}}, and the braces and semicolons would be added by the layout rule.
+{{{
+    import "base" -- searches in "base" package only
+        Prelude hiding (length)
+        Control.Exception
+        qualified Data.List as List
+
+    import ""   -- searches in home package only
+        A.B.C
+
+    import P.Q.R -- searches in home + exposed packages
+}}}