def 语句(self):
sub_tree = TreeNode('<语句>')
if isinstance(self.token, Identifier):
# assginment
child_tree, syntax_tree = self.赋值语句()
sub_tree.child = child_tree
# syntax_tree.print()
return sub_tree, syntax_tree
call_tab = {
'if':self.条件语句,
'while':self.当型循环语句,
'call':self.过程调用语句,
'read':self.读语句,
'write':self.写语句,
'begin':self.复合语句,
'repeat':self.重复语句,
}
if isinstance(self.token, Keyword) and self.token.value in call_tab:
# print("选择 {}".format(self.token.value))
child_tree, syntax_tree = call_tab[self.token.value]()
sub_tree.child = child_tree
return sub_tree, syntax_tree
else:
sub_tree.child = TreeNode("")
return sub_tree, SyntaxTree.EmptyStatement()
def 因子(self):
sub_tree = TreeNode('<因子>')
if isinstance(self.token, Identifier):
sub_tree.child = TreeNode(self.token)
syntax_tree = TreeNode(self.token)
self.token = self.lexer.forward()
return sub_tree, syntax_tree
if isinstance(self.token, Int):
sub_tree.child = TreeNode(self.token)
syntax_tree = TreeNode(self.token)
self.token = self.lexer.forward()
return sub_tree, syntax_tree
if isinstance(self.token, Delimiter) and self.token.value == '(':
child_tree = TreeNode(self.token)
self.token = self.lexer.forward()
expression = self.表达式()
child_tree.sublings.append(expression)
if isinstance(self.token, Delimiter) and self.token.value == ')':
child_tree.sublings.append(TreeNode(self.token))
sub_tree.child = child_tree
self.token = self.lexer.forward()
return sub_tree
else:
self.unexpected_error(')')
else:
self.unexpected_error('(')
def 复合语句(self):
sub_tree = TreeNode('<复合语句>')
ast_stmt_list = []
expect = 'begin'
if isinstance(self.token, Keyword) and self.token.value == 'begin':
child_tree = TreeNode(self.token)
self.token = self.lexer.forward()
statement, ast_stmt = self.语句()
child_tree.sublings.append(statement)
ast_stmt_list.append(ast_stmt)
while isinstance(self.token, Delimiter) and self.token.value == ';':
child_tree.sublings.append(TreeNode(self.token))
self.token = self.lexer.forward()
statement, ast_stmt = self.语句()
child_tree.sublings.append(statement)
ast_stmt_list.append(ast_stmt)
else:
expect = 'end'
if isinstance(self.token, Keyword) and self.token.value == 'end':
child_tree.sublings.append(TreeNode(self.token))
self.token = self.lexer.forward()
sub_tree.child = child_tree
syntax_tree = SyntaxTree.BlockStatement(*ast_stmt_list)
return sub_tree, syntax_tree
self.unexpected_error(expect)
def 重复语句(self):
sub_tree = TreeNode('<重复语句>')
stmt_list = []
expected = 'repeat'
if isinstance(self.token, Keyword) and self.token.value == 'repeat':
child_tree = TreeNode(self.token)
self.token = self.lexer.forward()
statement, ast_statement = self.语句()
stmt_list.append(ast_statement)
child_tree.sublings.append(statement)
while isinstance(self.token, Delimiter) and self.token.value == ';':
child_tree.sublings.append(TreeNode(self.token))
self.token = self.lexer.forward()
statement, ast_statement = self.语句()
stmt_list.append(ast_statement)
child_tree.sublings.append(statement)
else:
expected = 'until'
if isinstance(self.token, Keyword) and self.token.value == 'until':
child_tree.sublings.append(TreeNode(self.token))
self.token = self.lexer.forward()
condition, ast_condition = self.条件()
child_tree.sublings.append(condition)
sub_tree.child = child_tree
syntax_tree = SyntaxTree.DoWhileStatement(condition=ast_condition, statement=stmt_list)
return sub_tree, syntax_tree
self.unexpected_error(expected)
def 表达式(self):
sub_tree = TreeNode('<表达式>')
child_tree = None
heading_operator = None
syntax_tree = None
if isinstance(self.token, Operator) and self.token.value in ['+', '-']:
# TODO
child_tree = TreeNode(self.token)
heading_operator = self.token.value
self.token = self.lexer.forward()
anal_term, ast_term = self.项()
if child_tree is not None:
child_tree.sublings.append(anal_term)
else:
child_tree = anal_term
if heading_operator is None or heading_operator in ['+']:
syntax_tree = ast_term
else:
ast_heading_zero = TreeNode(Int(0))
syntax_tree = SyntaxTree.BinaryExpression(heading_operator, ast_heading_zero, ast_term)
while isinstance(self.token, Operator) and self.token.value in ['+', '-']:
anal_add, ast_add = self.加法运算符()
child_tree.sublings.append(anal_add)
anal_term, rhs_term = self.项()
syntax_tree = SyntaxTree.BinaryExpression(ast_add, syntax_tree, rhs_term)
child_tree.sublings.append(anal_term)
else:
sub_tree.child = child_tree
return sub_tree, syntax_tree
def 变量说明部分(self):
sub_tree = TreeNode('<变量说明部分>')
variable_declarator = []
expected = 'var'
if isinstance(self.token, Keyword) and self.token.value == 'var':
child_tree = TreeNode(self.token)
self.token = self.lexer.forward()
identifier, syntax_identifier = self.标识符()
variable_declarator.append(syntax_identifier)
child_tree.sublings.append(identifier)
while isinstance(self.token, Delimiter) and self.token.value == ',':
child_tree.sublings.append(TreeNode(self.token))
self.token = self.lexer.forward()
identifier, syntax_identifier = self.标识符()
variable_declarator.append(syntax_identifier)
child_tree.sublings.append(identifier)
else:
expected = ';'
if isinstance(self.token, Delimiter) and self.token.value == ';':
child_tree.sublings.append(TreeNode(self.token))
syntax_tree = SyntaxTree.VariableDeclaration(*variable_declarator)
self.token = self.lexer.forward()
sub_tree.child = child_tree
return sub_tree, syntax_tree
self.unexpected_error(expected)
def 无符号整数(self):
sub_tree = TreeNode('<无符号整数>')
if isinstance(self.token, Int):
sub_tree.child = TreeNode(self.token)
syntax_tree = TreeNode(self.token)
self.token = self.lexer.forward()
return sub_tree, syntax_tree
def 条件语句(self):
sub_tree = TreeNode('<条件语句>')
syntax_tree = None
if isinstance(self.token, Keyword) and self.token.value == 'if':
child_tree = TreeNode(self.token)
self.token = self.lexer.forward()
condition, ast_condition = self.条件()
child_tree.sublings.append(condition)
if isinstance(self.token, Keyword) and self.token.value == 'then':
child_tree.sublings.append(TreeNode(self.token))
self.token = self.lexer.forward()
statment, ast_true_stmt = self.语句()
child_tree.sublings.append(statment)
ast_false_stmt = SyntaxTree.EmptyStatement()
if isinstance(self.token, Keyword) and self.token.value == 'else':
child_tree.sublings.append(TreeNode(self.token))
self.token = self.lexer.forward()
statment, ast_false_stmt = self.语句()
child_tree.sublings.append(statment)
sub_tree.child = child_tree
syntax_tree = SyntaxTree.IfStatement(ast_condition, ast_true_stmt, false_stmt=ast_false_stmt)
return sub_tree, syntax_tree
else:
if self.lexer.hasnext():
statement = self.lexer.statement.split('\n')
pos_str = "{}\n{}".format(statement[self.lexer.line_index -1 ], " "*(self.lexer.character_index-2) )
pos_str += '^'
invalid_str = '"then" expected, get "{}" at line {}'.format(self.token.value, self.lexer.line_index)
raise SyntaxException("{}\n{}".format(invalid_str, pos_str))
else:
raise SyntaxException("{}".format('unexpected EOF!'))
else:
self.unexpected_error('if')
def 分程序(self):
sub_tree = TreeNode('<分程序>')
child_tree, ast_const_decl, ast_var_decl, ast_proc_decl, ast_smnt_tree = None, None, None, None, None
if isinstance(self.token, Keyword) and self.token.value == 'const':
child_tree, ast_const_decl = self.常量说明部分()
if isinstance(self.token, Keyword) and self.token.value == 'var':
anal_var_decl, ast_var_decl = self.变量说明部分()
if child_tree is None:
child_tree = anal_var_decl
else:
child_tree.sublings.append(anal_var_decl)
if isinstance(self.token, Keyword) and self.token.value == 'procedure':
anal_proc_decl, ast_proc_decl = self.过程说明部分()
if child_tree is None:
child_tree = anal_proc_decl
else:
child_tree.sublings.append(anal_proc_decl)
anal_smnt_tree, ast_smnt_tree = self.语句()
if child_tree is None:
child_tree = anal_smnt_tree
else:
child_tree.sublings.append(anal_smnt_tree)
sub_tree.child = child_tree
ast_tree = SyntaxTree.SubRoutine(const_decl=ast_const_decl, var_decl=ast_var_decl, proc_decl=ast_proc_decl,
stmt=ast_smnt_tree)
return sub_tree, ast_tree
def 标识符(self):
sub_tree = TreeNode('<标识符>')
if isinstance(self.token, Identifier):
sub_tree.child = TreeNode(self.token)
syntax_tree = TreeNode(self.token)
self.token = self.lexer.forward()
return sub_tree, syntax_tree
self.unexpected_error('identifier')
def 关系运算符(self):
sub_tree = TreeNode('<关系运算符>')
if isinstance(self.token, Operator):
if self.token.value in ['=', '<>', '<', '<=', '>', '>=']:
child_tree = TreeNode(self.token)
self.token = self.lexer.forward()
sub_tree.child = child_tree
return sub_tree, child_tree.data.value
self.unexpected_error('compare operator')
def 读语句(self):
sub_tree = TreeNode('<读语句>')
if isinstance(self.token, Keyword) and self.token.value == 'read':
io_type = TreeNode(self.token)
child_tree = TreeNode(self.token)
sub_tree.child = child_tree
self.token = self.lexer.forward()
ast_args = self.rw_arg(child_tree)
syntax_tree = SyntaxTree.IOStatement(io_type, ast_args)
return sub_tree, syntax_tree
def 程序(self):
sub_tree = TreeNode('<程序>')
child_tree, syntax_tree = self.分程序()
if isinstance(self.token, Delimiter) and self.token.value == '.':
child_tree.sublings.append(TreeNode(self.token))
self.token = self.lexer.forward()
sub_tree.child = child_tree
return sub_tree, syntax_tree
else:
self.unexpected_error('.')
def 项(self):
sub_tree = TreeNode('<项>')
child_tree, ast_tree = self.因子()
while isinstance(self.token, Operator) and self.token.value in ['*', '/']:
anal_mul, ast_mul = self.乘法运算符()
child_tree.sublings.append(anal_mul)
fractor, ast_fractor = self.因子()
ast_tree = SyntaxTree.BinaryExpression(ast_mul, ast_tree, ast_fractor)
child_tree.sublings.append(fractor)
else:
sub_tree.child = child_tree
return sub_tree, ast_tree
def 乘法运算符(self):
sub_tree = TreeNode('<乘法运算符>')
if isinstance(self.token, Operator):
if self.token.value == '*' or self.token.value == '/':
child_tree = TreeNode(self.token)
self.token = self.lexer.forward()
sub_tree.child = child_tree
return sub_tree, child_tree.data.value
else:
self.unexpected_error('* or /')
else:
self.unexpected_error('operator')
def 写语句(self):
sub_tree = TreeNode('<写语句>')
if isinstance(self.token, Keyword) and self.token.value == 'write':
io_type = TreeNode(self.token)
child_tree = TreeNode(self.token)
sub_tree.child = child_tree
self.token = self.lexer.forward()
ast_args = self.rw_arg(child_tree)
syntax_tree = SyntaxTree.IOStatement(io_type, ast_args)
return sub_tree, syntax_tree
else:
self.unexpected_error('write')
def 赋值语句(self):
sub_tree = TreeNode('<赋值语句>')
child_tree, ast_identifier_lhs = self.标识符()
if isinstance(self.token, Operator) and self.token.value == ':=':
child_tree.sublings.append(TreeNode(self.token))
self.token = self.lexer.forward()
expression, ast_identifier_rhs = self.表达式()
child_tree.sublings.append(expression)
sub_tree.child = child_tree
syntax_tree = SyntaxTree.AssignExpression(ast_identifier_lhs, ast_identifier_rhs)
return sub_tree, syntax_tree
else:
self.unexpected_error(':=')
def 常量定义(self):
analysis_tree = TreeNode('<常量定义>')
child_tree, syntax_indentifier = self.标识符()
if isinstance(self.token, Operator) and self.token.value == '=':
child_tree.sublings.append(TreeNode(self.token))
self.token = self.lexer.forward()
subling, syntax_int = self.无符号整数()
child_tree.sublings.append(subling)
analysis_tree.child = child_tree
syntax_tree = SyntaxTree.ConstDeclarator(syntax_indentifier, syntax_int)
return analysis_tree, syntax_tree
else:
self.unexpected_error('const')
def 过程调用语句(self):
sub_tree = TreeNode('<过程调用语句>')
expected = 'call'
if isinstance(self.token, Keyword) and self.token.value == 'call':
child_tree = TreeNode(self.token)
self.token = self.lexer.forward()
identifier, ast_identifier = self.标识符()
expected = 'identifier'
if identifier is not None:
child_tree.sublings.append(identifier)
sub_tree.child = child_tree
syntax_tree = SyntaxTree.CallExpression(identifier=ast_identifier)
return sub_tree, syntax_tree
self.unexpected_error(expected)
def 条件(self):
sub_tree = TreeNode('<条件>')
syntax_tree = None
if isinstance(self.token, Keyword) and self.token.value == 'odd':
child_tree = TreeNode(self.token)
self.token = self.lexer.forward()
expression, ast_expression = self.表达式()
syntax_tree = SyntaxTree.OddStatement(ast_expression)
else:
expression, ast_lhs = self.表达式()
child_tree = expression
operator, ast_operator = self.关系运算符()
child_tree.sublings.append(operator)
expression, ast_rhs = self.表达式()
syntax_tree = SyntaxTree.BinaryExpression(ast_operator, ast_lhs, ast_rhs)
child_tree.sublings.append(expression)
sub_tree.child = child_tree
return sub_tree, syntax_tree
def 当型循环语句(self):
sub_tree = TreeNode('<当型循环语句>')
expected = 'while'
if isinstance(self.token, Keyword) and self.token.value == 'while':
child_tree = TreeNode(self.token)
self.token = self.lexer.forward()
condition, ast_condition = self.条件()
child_tree.sublings.append(condition)
expected = 'do'
if isinstance(self.token, Keyword) and self.token.value == 'do':
child_tree.sublings.append(TreeNode(self.token))
self.token = self.lexer.forward()
statement, ast_stmt = self.语句()
child_tree.sublings.append(statement)
sub_tree.child = child_tree
syntax_tree = SyntaxTree.WhileStatement(condition=ast_condition, statement=ast_stmt)
return sub_tree, syntax_tree
self.unexpected_error(expected)
def 过程首部(self):
sub_tree = TreeNode('<过程首部>')
if isinstance(self.token, Keyword) and self.token.value == 'procedure':
child_tree = TreeNode(self.token)
self.token = self.lexer.forward()
identifier, ast_indetifier = self.标识符()
if identifier is not None:
child_tree.sublings.append(identifier)
if isinstance(self.token, Delimiter) and self.token.value == ';':
child_tree.sublings.append(TreeNode(self.token))
self.token = self.lexer.forward()
sub_tree.child = child_tree
return sub_tree, ast_indetifier
else:
self.unexpected_error(';')
else:
self.unexpected_error('identifier')
else:
self.unexpected_error('procedure')
def 常量说明部分(self):
analysis_tree = TreeNode('<常量说明部分>')
syntax_tree = SyntaxTree.ConstDeclaration()
if isinstance(self.token, Keyword) and self.token.value == 'const':
child_tree = TreeNode(self.token)
self.token = self.lexer.forward()
const_def, syntax_constdef = self.常量定义()
syntax_tree.insert(syntax_constdef)
child_tree.sublings.append(const_def)
while isinstance(self.token, Delimiter) and self.token.value == ',':
child_tree.sublings.append(TreeNode(self.token))
self.token = self.lexer.forward()
const_def, syntax_constdef = self.常量定义()
syntax_tree.insert(syntax_constdef)
child_tree.sublings.append(const_def)
else:
if isinstance(self.token, Delimiter) and self.token.value == ';':
child_tree.sublings.append(TreeNode(self.token))
self.token = self.lexer.forward()
analysis_tree.child = child_tree
return analysis_tree, syntax_tree
else:
self.unexpected_error('const')