Add remaining querying functions

Author: tarleb

README.md

@@ -332,6 +332,33 @@ If `a` and `b` are `Doc` elements, then `a // b` puts `a` above
 
 Returns `true` iff `doc` is the empty document, `false` otherwise.
 
+#### min_offset
+
+`min_offset (doc)`
+
+Returns the minimal width of a @'Doc'@ when reflowed at breakable
+spaces.
+
+#### update_column
+
+`update_column (doc, i)`
+
+Returns the column that would be occupied by the last laid out character.
+
+#### height
+
+`height (doc)`
+
+Returns the height of a block or other Doc.
+
+#### real_length
+
+`real_length (str)`
+
+Returns the real length of a string in a monospace font: 0 for a
+combining character, 1, for a regular character, 2 for an East
+Asian wide character.
+
 #### offset
 
 `offset (doc)`

src/Foreign/Lua/Module/DocLayout.hs

@@ -53,7 +53,11 @@ module Foreign.Lua.Module.DocLayout (
 
   -- * Document Querying
   , is_empty
+  , height
+  , min_offset
   , offset
+  , real_length
+  , update_column
 
   -- * Marshaling
   , peekDoc
@@ -116,6 +120,11 @@ pushModule = do
   -- querying
   Lua.addfunction "is_empty"   is_empty
   Lua.addfunction "offset"     offset
+  Lua.addfunction "height"     height
+  Lua.addfunction "min_offset" min_offset
+  Lua.addfunction "offset"     offset
+  Lua.addfunction "real_length" real_length
+  Lua.addfunction "update_column" update_column
   -- rendering
   Lua.addfunction "render" render
   return 1
@@ -143,6 +152,26 @@ is_empty = return . Doc.isEmpty
 offset :: Doc Text -> Lua Int
 offset = return . Doc.offset
 
+-- | Returns the minimal width of a @'Doc'@ when reflowed at
+-- breakable spaces.
+min_offset :: Doc Text -> Lua Int
+min_offset = return . Doc.minOffset
+
+-- | Returns the column that would be occupied by the last laid
+-- out character.
+update_column :: Doc Text -> Int -> Lua Int
+update_column doc = return . Doc.updateColumn doc
+
+-- | Returns the height of a block or other Doc.
+height :: Doc Text -> Lua Int
+height = return . Doc.height
+
+-- | Returns the real length of a string in a monospace font: 0
+-- for a combining character, 1, for a regular character, 2 for
+-- an East Asian wide character.
+real_length :: Text -> Lua Int
+real_length = return . Doc.realLength
+
 --
 -- Constructors
 --

test/test-doclayout.lua

@@ -60,10 +60,32 @@ return {
       assert.is_falsy(doclayout.is_empty('non-empty'))
     end),
 
+    test('height', function ()
+      assert.are_equal(doclayout.height(doclayout.empty), 1)
+      assert.are_equal(doclayout.height('line'), 1)
+      assert.are_equal(doclayout.height(doclayout.literal 'p' / 'q'), 2)
+      assert.are_equal(doclayout.height(doclayout.literal 'p' // 'q'), 3)
+    end),
+
+    test('min_offset', function ()
+      assert.are_equal(doclayout.min_offset 'four', 4)
+      assert.are_equal(
+        doclayout.min_offset(doclayout.literal 'four' + 'radio'),
+        5
+      )
+    end),
+
     test('offset', function ()
       assert.are_equal(doclayout.offset 'four', 4)
       assert.are_equal(doclayout.offset(doclayout.literal 'four' / 'radio'), 5)
-    end)
+    end),
+
+    test('real_length', function ()
+      assert.are_equal(doclayout.real_length(''), 0)
+      assert.are_equal(doclayout.real_length('a'), 1)
+      assert.are_equal(doclayout.real_length('❄'), 1)
+      assert.are_equal(doclayout.real_length('シ'), 2)
+    end),
   },
 
   group 'Doc type' {