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<body><div>I like the idea here, but I'm not sold on the syntax. I also do explicitly want an `import qualified`. And with qualified imports, I question whether we really need to support renaming in the import syntax here.<br></div>
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<div>I'm tempted to say we should just crib Haskell's import rules (<a href="https://wiki.haskell.org/Import">https://wiki.haskell.org/Import</a>), with the minor change that importing members by name still makes them accessible via the module name too (in Haskell `import Mod (x, y)` makes `x` and `y` visible but does not make `Mod.x` or `Mod.y` visible). This lets you say things like<br></div>
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<div><span class="font" style="font-family: menlo, consolas, "courier new", monospace, sans-serif;"><b>import</b> Mod // imports Mod and all its members<br></span></div>
<div><span class="font" style="font-family: menlo, consolas, "courier new", monospace, sans-serif;"><b>import</b> Mod () // only provides access to protocol conformances declared in Mod, doesn't actually <b>import</b> anything</span><span class="font" style="font-family: menlo, consolas, "courier new", monospace, sans-serif;"><br></span></div>
<div><span class="font" style="font-family: menlo, consolas, "courier new", monospace, sans-serif;"><b>import</b> Mod <b>(</b>x,y<b>)</b> // imports `x` and `y`, which are also accessible as e.g. `Mod.x`, but does not provide `z` or `Mod.z`</span><span class="font" style="font-family: menlo, consolas, "courier new", monospace, sans-serif;"><br></span></div>
<div><span class="font" style="font-family: menlo, consolas, "courier new", monospace, sans-serif;"><b>import qualified</b> Mod // imports Mod but all access to members has to go through it, e.g. `Mod.x`</span><span class="font" style="font-family: menlo, consolas, "courier new", monospace, sans-serif;"><br></span></div>
<div><span class="font" style="font-family: menlo, consolas, "courier new", monospace, sans-serif;"><b>import qualified</b> Mod <b>(</b>x,y<b>)</b> // imports Mod but only provides access to `Mod.x` and `Mod.y` but not e.g. `Mod.z`</span><span class="font" style="font-family: menlo, consolas, "courier new", monospace, sans-serif;"><br></span></div>
<div><span class="font" style="font-family: menlo, consolas, "courier new", monospace, sans-serif;"><b>import </b>Mod <b>hiding</b> <b>(</b>x,y<b>)</b> // imports Mod and its members except for `x` or `y`<br></span></div>
<div><span class="font" style="font-family: menlo, consolas, "courier new", monospace, sans-serif;"><b>import qualified</b> Mod <b>hiding</b> <b>(</b>x,y<b>)</b> // imports e.g. `Mod.z` but not `Mod.x` or `Mod.y`</span><span class="font" style="font-family: menlo, consolas, "courier new", monospace, sans-serif;"><b><br></b></span></div>
<div><span class="font" style="font-family: menlo, consolas, "courier new", monospace, sans-serif;"><b>import</b> Mod <b>as</b> Foo // imports Mod and renames the module to Foo, so e.g. `x` and `Foo.x` are accessible<br></span></div>
<div><span class="font" style="font-family: menlo, consolas, "courier new", monospace, sans-serif;"><b>import</b> Mod <b>as</b> Foo <b>(</b>x,y<b>)</b> // renames Mod to Foo, provides `x`, `y`, `Foo.x`, and `Foo.y`</span><span class="font" style="font-family: menlo, consolas, "courier new", monospace, sans-serif;"><br></span></div>
<div><span class="font" style="font-family: menlo, consolas, "courier new", monospace, sans-serif;"><b>import qualified</b> Mod <b>as</b> Foo // renames Mod to Foo, all members are accessible via the module e.g. `Foo.x`</span><span class="font" style="font-family: menlo, consolas, "courier new", monospace, sans-serif;"><br></span></div>
<div><span class="font" style="font-family: menlo, consolas, "courier new", monospace, sans-serif;"><b>import qualified</b> Mod <b>as</b> Foo <b>(</b>x,y<b>)</b> // renames Mod to Foo, provides access to `Foo.x` and `Foo.y` but not e.g. `Foo.z`</span><span class="font" style="font-family: menlo, consolas, "courier new", monospace, sans-serif;"><br></span></div>
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<div>Furthermore, you can have multiple import statements from the same module, so you can say something like<br></div>
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<div><span class="font" style="font-family: menlo, consolas, "courier new", monospace, sans-serif;"><b>import qualified</b> Mod</span></div>
<div><span class="font" style="font-family: menlo, consolas, "courier new", monospace, sans-serif;"><b>import</b> Mod <b>(</b>x,y<b>)</b><br></span></div>
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<div>to provide access to all of Mod qualified with the name, and additionally import `x` and `y` as unqualified identifiers.<br></div>
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<div>-Kevin Ballard</div>
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