Start execution;

execute.lua

@@ -0,0 +1,99 @@
+local function getArgumentValue(value, context)
+  return nil -- TODO
+end
+
+local function getFieldEntryKey(selection)
+  return selection.alias and selection.alias.name.value or selection.name.value
+end
+
+local function shouldIncludeNode(selection, context)
+  if selection.directives then
+    for _, directive in ipairs(selection.directives) do
+      if directive.name.value == 'skip' then
+        for _, argument in ipairs(directive.arguments) do
+          if argument.name == 'if' and getArgumentValue(argument.value, context) then
+            return false
+          end
+        end
+      elseif directive.name.value == 'include' then
+        for _, argument in ipairs(directive.arguments) do
+          if argument.name == 'if' and not getArgumentValue(argument.value, context) then
+            return false
+          end
+        end
+      end
+    end
+  end
+
+  return true
+end
+
+local function collectFields(selectionSet, type, fields, visitedFragments, context)
+  for _, selection in ipairs(selectionSet.selections) do
+    if selection.kind == 'field' then
+      if shouldIncludeNode(selection) then
+        local name = getFieldEntryKey(selection)
+        fields[name] = fields[name] or {}
+        table.insert(fields[name], selection)
+      end
+    elseif selection.kind == 'inlineFragment' then
+      if shouldIncludeNode(selection) and doesFragmentApply(selection, type) then
+        collectFields(selection.selectionSet, type, fields, visitedFragments, context)
+      end
+    elseif selection.kind == 'fragmentSpread' then
+      local fragmentName = selection.name.value
+      if shouldIncludeNode(selection) and not visitedFragments[fragmentName] then
+        visitedFragments[fragmentName] = true
+        local fragment = context.fragmentMap[fragmentName]
+        if fragment and shouldIncludeNode(fragment) and doesFragmentApply(fragment, type) then
+          collectFields(fragment.selectionSet, type, fields, visitedFragments, context)
+        end
+      end
+    end
+  end
+
+  return fields
+end
+
+local function buildContext(schema, tree, variables, operationName)
+  local context = {
+    schema = schema,
+    operation = nil,
+    fragmentMap = {}
+  }
+
+  for _, definition in ipairs(tree.definitions) do
+    if definition.kind == 'operation' then
+      if not operationName and context.operation then
+        error('Operation name must be specified if more than one operation exists.')
+      end
+
+      if not operationName or definition.name.value == operationName then
+        context.operation = definition
+      end
+    elseif definition.kind == 'fragmentDefinition' then
+      context.fragmentMap[definition.name.value] = definition
+    end
+  end
+
+  if not context.operation then
+    if operationName then
+      error('Unknown operation "' .. operationName .. '"')
+    else
+      error('Must provide an operation')
+    end
+  end
+
+  return context
+end
+
+return function(schema, tree, variables, operationName)
+  local context = buildContext(schema, tree, variables, operationName)
+  local rootType = schema[context.operation.operation]
+
+  if not rootType then
+    error('Unsupported operation "' .. context.operation.operation .. '"')
+  end
+
+  local fields = collectFields(context.operation.selectionSet, rootType, {}, {}, context)
+end