(* This Source Code Form is subject to the terms of the Mozilla Public License,
  v. 2.0. If a copy of the MPL was not distributed with this file, You can
  obtain one at https://mozilla.org/MPL/2.0/. *)
module
import common, lexer

type
	ElnaListNode* = record
		next: ^ElnaListNode
	end
	ElnaList* = record
		first: ^ElnaListNode;
		last: ^ElnaListNode
	end

	(* Type representation. *)
	ElnaTypeKind* = (primitive, enumeration, _record, pointer, array, alias, procedure)
	ElnaType* = record
		kind: ElnaTypeKind;
		size: Word;
		alignment: Word
	end
	ElnaTypeAlias* = record(ElnaType)
		base: ^ElnaType
	end
	ElnaTypeEnumeration* = record(ElnaType)
		members: ^[]const Word8;
		length: Word
	end
	ElnaTypeField* = record
		name: []const Word8;
		field_type: ^ElnaType
	end
	ElnaTypeRecord* = record(ElnaType)
		members: ^ElnaTypeField;
		length: Word
	end
	ElnaTypePointer* = record(ElnaType)
		base: ^ElnaType
	end
	ElnaTypeArray* = record(ElnaType)
		base: ^ElnaType;
		length: Word
	end
	ElnaTypeProcedure* = record(ElnaType)
		return_type: ^ElnaType
	end

	(* Abstract syntax tree nodes. *)
	ElnaTreeKind* = (
		integer_literal,
		string_literal,
		character_literal,
		boolean_literal,
		variable_expression,
		field_access_expression,
		dereference_expression,
		unary_expression,
		binary_expression,
		call,
		call_statement,
		goto_statement,
		label_declaration,
		return_statement,
		assign_statement,
		if_statement,
		procedure_declaration,
		variable_declaration,
		enumeration_type_expression,
		named_type_expression,
		type_declaration,
		module_declaration,
		record_type_expression,
		pointer_type_expression,
		array_type_expression,
		null,
		trait_expression,
		array_access_expression,
		_cast
	)
	ElnaTreeNode* = record
		kind: ElnaTreeKind;
		position: ElnaPosition
	end
	ElnaTreeTypeExpression* = record(ElnaTreeNode)
	end
	ElnaTreeExpression* = record(ElnaTreeNode)
		type_decoration: ^ElnaType
	end
	ElnaTreeIntegerLiteral* = record(ElnaTreeExpression)
		value: Word
	end
	ElnaTreeCharacterLiteral* = record(ElnaTreeExpression)
		value: Word8
	end
	ElnaTreeNilLiteral* = record(ElnaTreeExpression)
	end
	ElnaTreeBooleanLiteral* = record(ElnaTreeExpression)
		value: Bool
	end
	ElnaTreeStringLiteral* = record(ElnaTreeExpression)
		value: []const Word8
	end
	ElnaTreeVariableExpression* = record(ElnaTreeExpression)
		name: []const Word8
	end
	ElnaTreeCastExpression* = record(ElnaTreeExpression)
		expression: ^ElnaTreeExpression;
		type_expression: ^ElnaTreeTypeExpression
	end
	ElnaTreeDereferenceExpression* = record(ElnaTreeExpression)
		pointer: ^ElnaTreeExpression
	end
	ElnaTreeBinaryExpression* = record(ElnaTreeExpression)
		lhs: ^ElnaTreeExpression;
		rhs: ^ElnaTreeExpression;
		operator: ElnaLexerKind
	end
	ElnaTreeUnaryExpression* = record(ElnaTreeExpression)
		operand: ^ElnaTreeExpression;
		operator: ElnaLexerKind
	end
	ElnaTreeFieldAccessExpression* = record(ElnaTreeExpression)
		aggregate: ^ElnaTreeExpression;
		field: []const Word8
	end
	ElnaTreeArrayAccessExpression* = record(ElnaTreeExpression)
		array: ^ElnaTreeExpression;
		index: ^ElnaTreeExpression
	end
	ElnaTreeTraitExpression* = record(ElnaTreeExpression)
		name: []const Word8;
		argument: ^ElnaTreeTypeExpression
	end
	ElnaTreeExpressionList* = record
		expression: ^ElnaTreeExpression;
		next: ^ElnaTreeExpressionList
	end
	ElnaTreeCall* = record(ElnaTreeExpression)
		callee: ^ElnaTreeVariableExpression;
		arguments: ^ElnaTreeExpressionList;
		count: Word
	end

	(* Statements. *)
	ElnaTreeStatement* = record(ElnaTreeNode)
		next: ^ElnaTreeStatement
	end
	ElnaTreeConditionalStatements* = record
		condition: ^ElnaTreeExpression;
		statements: ^ElnaTreeStatement;
		next: ^ElnaTreeConditionalStatements
	end
	ElnaTreeIfStatement* = record(ElnaTreeStatement)
		conditionals: ^ElnaTreeConditionalStatements;
		_else: ^ElnaTreeStatement
	end
	ElnaTreeGotoStatement* = record(ElnaTreeStatement)
		label: []const Word8
	end
	ElnaTreeAssignStatement* = record(ElnaTreeStatement)
		assignee: ^ElnaTreeExpression;
		assignment: ^ElnaTreeExpression
	end
	ElnaTreeReturnStatement* = record(ElnaTreeStatement)
		returned: ^ElnaTreeExpression
	end
	ElnaTreeLabelDeclaration* = record(ElnaTreeStatement)
		label: []const Word8
	end
	ElnaTreeCallStatement* = record(ElnaTreeStatement)
		call: ^ElnaTreeCall
	end

	(* Type expressions. *)
	ElnaTreeEnumeration* = record
		name: []const Word8;
		next: ^ElnaTreeEnumeration
	end
	ElnaTreeEnumerationTypeExpression* = record(ElnaTreeTypeExpression)
		members: ^ElnaTreeEnumeration;
		length: Word
	end
	ElnaTreeField* = record
		name: []const Word8;
		type_expression: ^ElnaTreeTypeExpression;
		next: ^ElnaTreeField
	end
	ElnaTreeRecordTypeExpression* = record(ElnaTreeTypeExpression)
		members: ^ElnaTreeField;
		length: Word;
		parent: []const Word8
	end
	ElnaTreeNamedTypeExpression* = record(ElnaTreeTypeExpression)
		name: []const Word8
	end
	ElnaTreePointerTypeExpression* = record(ElnaTreeTypeExpression)
		base: ^ElnaTreeTypeExpression
	end
	ElnaTreeArrayTypeExpression* = record(ElnaTreeTypeExpression)
		base: ^ElnaTreeTypeExpression;
		length: ^ElnaTreeExpression
	end

	(* Declarations. *)
	ElnaTreeDeclaration* = record(ElnaTreeNode)
		next: ^ElnaTreeDeclaration;
		name: []const Word8
	end
	ElnaTreeVariableDeclaration* = record(ElnaTreeDeclaration)
		type_expression: ^ElnaTreeTypeExpression
	end
	ElnaTreeProcedureDeclaration* = record(ElnaTreeDeclaration)
		body: ^ElnaTreeStatement;
		temporaries: ^ElnaTreeVariableDeclaration;
		parameters: ^ElnaTreeVariableDeclaration;
		return_type: ^ElnaTreeTypeExpression;
		is_extern: Bool
	end
	ElnaTreeTypeDeclaration* = record(ElnaTreeDeclaration)
		type_expression: ^ElnaTreeTypeExpression
	end
	ElnaTreeModuleDeclaration* = record(ElnaTreeNode)
		types: ^ElnaTreeDeclaration;
		globals: ^ElnaTreeVariableDeclaration;
		procedures: ^ElnaTreeProcedureDeclaration;
		body: ^ElnaTreeStatement
	end

proc elna_list_initialize*(list: ^ElnaList)
begin
	list^.first := nil;
	list^.last := nil
return

proc elna_list_append*(list: ^ElnaList; element: ^ElnaListNode) -> ^ElnaListNode
begin
	if element <> nil then
		if list^.first = nil then
			list^.first := element
		else
			list^.last^.next := element
		end;
		list^.last := element
	end
return element

proc elna_list_prepend*(list: ^ElnaList; element: ^ElnaListNode)
begin
	element^.next := list^.first;
	list^.first := element;
	if list^.last = nil then
		list^.last := element
	end
return

proc elna_list_insert*(list: ^ElnaList; existing, new: ^ElnaListNode)
begin
	if existing^.next = nil then
		list^.last := new
	else
		new^.next := existing^.next
	end;
	existing^.next := new
return

proc elna_list_empty*(list: ^ElnaList) -> Bool
return list^.first = nil

end.