Add diagnostic to enforce lowercase local element names (#6)

- diagnostic `uppercase-local` in group `conventions`, disabled by
default
- isolated unit tests for diagnostic

2 files changed, 48 insertions, 0 deletions

diff --git a/script/core/diagnostics/uppercase-local.lua b/script/core/diagnostics/uppercase-local.lua
new file mode 100644
index 00000000..cc377dd2
--- /dev/null
+++ b/script/core/diagnostics/uppercase-local.lua
@@ -0,0 +1,47 @@
+local files     = require 'files'
+local guide     = require 'parser.guide'
+local lang      = require 'language'
+
+local function isDocClass(source)
+    if not source.bindDocs then
+        return false
+    end
+    for _, doc in ipairs(source.bindDocs) do
+        if doc.type == 'doc.class' then
+            return true
+        end
+    end
+    return false
+end
+
+-- If local elements must be named lowercase by coding convention, this diagnostic helps with reminding about that
+return function (uri, callback)
+    local ast = files.getState(uri)
+    if not ast then
+        return
+    end
+
+    guide.eachSourceType(ast.ast, 'local', function (source)
+        local name = guide.getKeyName(source)
+        if not name then
+            return
+        end
+        local first = name:match '%w' -- alphanumeric character
+        if not first then
+            return
+        end
+        if not first:match '%u' then -- uppercase
+            return
+        end
+        -- If the assignment is marked as doc.class, then it is considered allowed 
+        if isDocClass(source) then
+            return
+        end
+        
+        callback {
+            start   = source.start,
+            finish  = source.finish,
+            message = lang.script('DIAG_UPPERCASE_LOCAL', name),
+        }
+    end)
+end
diff --git a/script/proto/diagnostic.lua b/script/proto/diagnostic.lua
index 24ab0814..48a9094c 100644
--- a/script/proto/diagnostic.lua
+++ b/script/proto/diagnostic.lua
@@ -173,6 +173,7 @@ m.register {
 
 m.register {
     'global-element',
+    'uppercase-local',
 } {
     group   = 'conventions',
     severity = 'Warning',