def optimize(syntax_tree, sql):
if syntax_tree.operator == 'SELECT':
condition = syntax_tree.condition
sql = condition.split('&')
relation = []
for i in range(len(sql)):
if search(sql[i]) is not None:
relation.append(search(sql[i]))
syntax_tree = optimize(syntax_tree.left_child, sql)
elif syntax_tree.operator == 'PROJECTION':
syntax_tree.left_child = optimize(syntax_tree.left_child, sql)
elif syntax_tree.operator == 'JOIN':
first_tree = SyntaxTree()
first_tree.operator = 'SELECT'
first_tree.condition = sql[0]
first_tree.left_child = syntax_tree.left_child
syntax_tree.left_child = first_tree
if len(sql) == 1:
return syntax_tree
second_tree = SyntaxTree()
second_tree.operator = 'SELECT'
second_tree.condition = sql[1]
second_tree.right_child = syntax_tree.right_child
syntax_tree.right_child = second_tree
return syntax_tree
def parse(sql_statement):
sql = sql_statement.split()
execute_tree = SyntaxTree()
index = 0
while True:
if index >= len(sql):
break
#处理一元运算符
elif sql[index] == 'SELECT' or sql[index] == 'PROJECTION':
execute_tree.operator = sql[index]
index += 2 # 从[开始到]里面的全部记录下来
condition = ''
while sql[index] != ']':
condition += sql[index]
condition += ' '
index += 1
index += 1
execute_tree.condition = condition
#处理二元运算符
elif sql[index] == 'JOIN':
# 连接操作需要创建子树，所以分开写
execute_tree.operator = sql[index]
execute_tree.left_child = SyntaxTree()
execute_tree.left_child.attribute = sql[index - 1]
execute_tree.right_child = SyntaxTree()
execute_tree.right_child.attribute = sql[index + 1]
index += 1
#处理子查询，进行递归
elif sql[index] == '(':
index += 1
statement = ''
while index < len(sql) and sql[index] != ')':
statement += sql[index]
statement += ' '
index += 1
index += 1
execute_tree.left_child = parse(statement)
else:
index += 1
return execute_tree
def parse(sql_statement):
sql = sql_statement.split()
execute_tree = SyntaxTree()
index = 0
while True:
if index >= len(sql):
break
elif sql[index] == 'SELECT' or sql[index] == 'PROJECTION':
execute_tree.operator = sql[index]
index += 2 # 从[开始到]里面的全部记录下来
condition = ''
while sql[index] != ']':
condition += sql[index]
condition += ' '
index += 1
index += 1
execute_tree.condition = condition
elif sql[index] == 'JOIN':
# 连接操作需要创建子树，所以分开写
execute_tree.operator = sql[index]
execute_tree.left_child = SyntaxTree()
execute_tree.left_child.attribute = sql[index - 1]
execute_tree.right_child = SyntaxTree()
execute_tree.right_child.attribute = sql[index + 1]
index += 1
elif sql[index] == '(':
# 每次遇到这个说明需要创建一棵子树，由于题目中的查询都是只有一个分支，所以可以直接进入下一个子树中
index += 1
statement = ''
while index < len(sql) and sql[index] != ')':
statement += sql[index]
statement += ' '
index += 1
index += 1
execute_tree.left_child = parse(statement)
else:
index += 1
return execute_tree
from syntaxtree import SyntaxTree
from wordbank import WordBank
import config
import builder
if __name__ == '__main__':
tree = SyntaxTree()
config.load_rules('rules.config', tree)
bank = WordBank()
config.load_words('words.csv', bank)
print(builder.build_sentence(tree, bank, 'S'))
def analyze(self, toks, text, semantic=False, context=None):
if not toks:
return SyntaxTree(TokenType.END), []
err_strs = []
status_stack = [0]
sym_stack = [SyntaxTree(TokenType.END)]
tok_idx = 0
accept = False
if context is None:
context = SemanticContext()
if toks[-1] != TokenType.END:
toks = toks + [Token(TokenType.END, None, 0, -1)]
while tok_idx < len(toks):
tok = toks[tok_idx]
if tok.type == TokenType.CCOMMENT:
tok_idx += 1
continue
toktype = tok.type
status = status_stack[-1]
if self._has_error(status, toktype):
err_strs.append(self._gen_err_str(tok, text))
tok_idx += 1
continue
act, number = self.action_table[status][toktype]
if act == ActionType.MOVE:
tok_idx += 1
status_stack.append(number)
sym_stack.append(SyntaxTree(tok))
elif act == ActionType.REDUCE:
production = self.productions[number]
parent = SyntaxTree(production.lhs)
for exp_sym in reversed(production.rhs):
status_stack.pop()
sym = sym_stack.pop()
assert sym.get_sym_name() == str(
exp_sym), "Expect {} but get {}".format(
exp_sym, sym.get_sym_name())
parent.add_child(sym)
parent.childs = parent.childs[::-1]
sym_stack.append(parent)
act, idx = self.action_table[status_stack[-1]][parent.sym]
assert act == ActionType.GOTO
status_stack.append(idx)
# do action
if semantic and production.action:
print(production.action.name)
try:
ret = production.action.do_action(parent, context)
if ret:
err_code, message = ret
else:
err_code = 0
except Exception as ex:
print(''.join(ex.args))
if err_code:
node = parent
while node.childs:
node = node.childs[0]
row, col = count_position(text, node.sym.start)
err_strs.append("{}:{} {}".format(row, col, message))
elif act == ActionType.ACCEPT:
accept = True
break
else:
assert False
if not accept:
err_strs.append("Expect More Token")
sym = SyntaxTree("Incomplete")
while sym_stack:
sym.add_child(sym_stack.pop())
sym_stack.append(sym)
return sym_stack.pop(), err_strs