chore: support parsing empty yaml

spec/dupekey_spec.lua

@@ -1,7 +1,3 @@
--- .vscode/settings.json <<
---   "Lua.workspace.library": {
---     "C:\\ProgramData\\chocolatey\\lib\\luarocks\\luarocks-2.4.4-win32\\systree\\share\\lua\\5.1": true
---   },
 local busted = require 'busted'
 local assert = require 'luassert'
 local yaml = require 'tinyyaml'
@@ -66,4 +62,4 @@ busted.describe("duplicate keys", function()
       )
     end)
   end)
-end)
+end)

spec/empty_spec.lua

@@ -0,0 +1,23 @@
+-- .vscode/settings.json <<
+--   "Lua.workspace.library": {
+--     "C:\\ProgramData\\chocolatey\\lib\\luarocks\\luarocks-2.4.4-win32\\systree\\share\\lua\\5.1": true
+--   },
+local busted = require 'busted'
+local assert = require 'luassert'
+local yaml = require 'tinyyaml'
+
+busted.describe("empty", function()
+
+  busted.it("empty:", function()
+    assert.same(
+      nil,
+      yaml.parse([[]])
+    )
+    assert.same(
+      nil,
+      yaml.parse([[
+        #END
+      ]])
+    )
+  end)
+end)

spec/example_spec.lua

@@ -1,7 +1,3 @@
--- .vscode/settings.json <<
---   "Lua.workspace.library": {
---     "C:\\ProgramData\\chocolatey\\lib\\luarocks\\luarocks-2.4.4-win32\\systree\\share\\lua\\5.1": true
---   },
 local busted = require 'busted'
 local assert = require 'luassert'
 local yaml = require 'tinyyaml'

spec/map_spec.lua

@@ -1,7 +1,3 @@
--- .vscode/settings.json <<
---   "Lua.workspace.library": {
---     "C:\\ProgramData\\chocolatey\\lib\\luarocks\\luarocks-2.4.4-win32\\systree\\share\\lua\\5.1": true
---   },
 local busted = require 'busted'
 local assert = require 'luassert'
 local yaml = require 'tinyyaml'
@@ -58,7 +54,7 @@ busted.describe("map", function()
         },
         yaml.parse([[
           a:
-          - b:  
+          - b:
               c:  1
           ]])
         )

spec/seq_spec.lua

@@ -1,7 +1,3 @@
--- .vscode/settings.json <<
---   "Lua.workspace.library": {
---     "C:\\ProgramData\\chocolatey\\lib\\luarocks\\luarocks-2.4.4-win32\\systree\\share\\lua\\5.1": true
---   },
 local busted = require 'busted'
 local assert = require 'luassert'
 local yaml = require 'tinyyaml'

spec/string_spec.lua

@@ -1,7 +1,3 @@
--- .vscode/settings.json <<
---   "Lua.workspace.library": {
---     "C:\\ProgramData\\chocolatey\\lib\\luarocks\\luarocks-2.4.4-win32\\systree\\share\\lua\\5.1": true
---   },
 local busted = require 'busted'
 local assert = require 'luassert'
 local yaml = require 'tinyyaml'

tinyyaml.lua

@@ -717,7 +717,7 @@ end
 -- : (list<str>)->dict
 local function parsedocuments(lines)
   lines = select(lines, function(s) return not isemptyline(s) end)
-
+  if #lines == 0 then return nil end
   if sfind(lines[1], '^%%YAML') then tremove(lines, 1) end
 
   local root = {}
@@ -781,7 +781,9 @@ local function parse(source)
   end
 
   local docs = parsedocuments(lines)
-  if #docs == 1 then
+  if docs == nil then
+    return nil
+  elseif #docs == 1 then
     return docs[1]
   end