系列入口:编程实战:类C语法的编译型脚本解释器(系列)-CSDN博客
前文已经介绍了编译入口,核心就是语句,本文介绍语句的编译。
目录
一、代码概览
二、辅助函数
2.1 tokens.IsPosNotToken(pos)
2.2 tokens.MoveCurrentToken(pToken, pos)
2.3 tokens.IsDelimiter(pos, ";")
2.4 tokens.MoveNextToken(pToken, pos)
2.5 tokens.IsOperator(pos, "(")
三、流程分析
一、代码概览
代码太长,直接贴:
bool GetSentence(CTokens& tokens, T_VARIABLE_S& vars, Sentence& sentence, Token*& pToken, size_t& pos){sentence.clear();Expression* pExpression;if (tokens.IsPosNotToken(pos))return false;sentence.source_start = tokens.TokenStart(pos);sentence.source_end = tokens.TokenStart(pos);tokens.MoveCurrentToken(pToken, pos);switch (pToken->type){case Token::IDENTIFIER:case Token::NUMBER:case Token::STRING:case Token::OPERATOR:sentence.type = Sentence::EXPRESSION;pExpression = GetExpression(tokens, vars, NULL, pos, ";");if (!tokens.IsPosNotToken(pos) && tokens.IsDelimiter(pos, ";")){tokens.MoveNextToken(pToken, pos);}sentence.expressions.reserve(1);sentence.expressions.push_back(*pExpression);break;case Token::DELIMITER:if (pToken->text == "{"){sentence.type = Sentence::BLOCK;tokens.MoveNextToken(pToken, pos);while (true){if (tokens.IsPosNotToken(pos))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "未期待的脚本结束,块语句未结束");if (tokens.IsDelimiter(pos, "}")){tokens.MoveNextToken(pToken, pos);break;}Sentence tmpsentence;if (!GetSentence(tokens, vars, tmpsentence, pToken, pos))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "获取块语句的语句出错");sentence.sentences.reserve(sentence.sentences.size() + 1);sentence.sentences.push_back(tmpsentence);}}else if (pToken->text == "}"){CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "未期待的块语句结束标记");}else if (pToken->text == ";"){sentence.type = Sentence::NULLSENTENCE;tokens.MoveNextToken(pToken, pos);}else{CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "尚未支持的分隔符");}break;case Token::KEYWORD:if (pToken->text == "return"){sentence.type = Sentence::RETURN;tokens.MoveNextToken(pToken, pos);pExpression = GetExpression(tokens, vars, NULL, pos, ";");Expression null_expression;if (NULL == pExpression){pExpression = &null_expression;}if (!tokens.IsPosNotToken(pos) && tokens.IsDelimiter(pos, ";")){tokens.MoveNextToken(pToken, pos);}sentence.expressions.reserve(1);sentence.expressions.push_back(*pExpression);}else if (pToken->text == "if"){sentence.type = Sentence::IF;tokens.MoveNextToken(pToken, pos);if (tokens.IsPosNotToken(pos))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "未期待的脚本结束,期待左括号");if (!tokens.IsOperator(pos, "("))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "期待左括号");tokens.MoveNextToken(pToken, pos);if (tokens.IsPosNotToken(pos))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "未期待的脚本结束,期待条件表达式");if (NULL == (pExpression = GetExpression(tokens, vars, NULL, pos, ")")))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "条件表达式为空");if (tokens.IsPosNotToken(pos))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "未期待的脚本结束,期待右括号");if (!tokens.IsOperator(pos, ")"))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "期待右括号");sentence.expressions.reserve(1);sentence.expressions.push_back(*pExpression);tokens.MoveNextToken(pToken, pos);sentence.sentences.reserve(2);Sentence if_sentence;if (!GetSentence(tokens, vars, if_sentence, pToken, pos))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "分析if块的执行语句出错");sentence.sentences.push_back(if_sentence);if (!tokens.IsPosNotToken(pos)){if (pToken->type == Token::KEYWORD && pToken->text == "else"){tokens.MoveNextToken(pToken, pos);Sentence else_sentence;if (!GetSentence(tokens, vars, else_sentence, pToken, pos))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "分析else块的执行语句出错");sentence.sentences.push_back(else_sentence);}}}else if (pToken->text == "do"){sentence.type = Sentence::DO;tokens.MoveNextToken(pToken, pos);sentence.sentences.reserve(1);Sentence if_sentence;if (!GetSentence(tokens, vars, if_sentence, pToken, pos))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "分析do块的执行语句出错");sentence.sentences.push_back(if_sentence);if (tokens.IsPosNotToken(pos))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "未期待的脚本结束,期待while");if (pToken->type != Token::KEYWORD || pToken->text != "while")CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "期待while");tokens.MoveNextToken(pToken, pos);if (tokens.IsPosNotToken(pos))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "未期待的脚本结束,期待左括号");if (!tokens.IsOperator(pos, "("))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "期待左括号");tokens.MoveNextToken(pToken, pos);if (tokens.IsPosNotToken(pos))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "未期待的脚本结束,期待条件表达式");if (NULL == (pExpression = GetExpression(tokens, vars, NULL, pos, ")")))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "条件表达式为空");tokens.MoveCurrentToken(pToken, pos);if (tokens.IsPosNotToken(pos))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "未期待的脚本结束,期待右括号");if (!tokens.IsOperator(pos, ")"))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "期待右括号");sentence.expressions.reserve(1);sentence.expressions.push_back(*pExpression);tokens.MoveNextToken(pToken, pos);if (tokens.IsPosNotToken(pos))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "未期待的脚本结束,期待分号");if (!tokens.IsDelimiter(pos, ";"))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "期待分号");tokens.MoveNextToken(pToken, pos);}else if (pToken->text == "while"){sentence.type = Sentence::WHILE;tokens.MoveNextToken(pToken, pos);if (tokens.IsPosNotToken(pos))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "未期待的脚本结束,期待左括号");if (!tokens.IsOperator(pos, "("))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "期待左括号");tokens.MoveNextToken(pToken, pos);if (tokens.IsPosNotToken(pos))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "未期待的脚本结束,期待条件表达式");if (NULL == (pExpression = GetExpression(tokens, vars, NULL, pos, ")")))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "条件表达式为空");if (tokens.IsPosNotToken(pos))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "未期待的脚本结束,期待右括号");if (!tokens.IsOperator(pos, ")"))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "期待右括号");sentence.expressions.reserve(1);sentence.expressions.push_back(*pExpression);tokens.MoveNextToken(pToken, pos);sentence.sentences.reserve(1);Sentence if_sentence;if (!GetSentence(tokens, vars, if_sentence, pToken, pos))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "分析while块的执行语句出错");sentence.sentences.push_back(if_sentence);}else if (pToken->text == "for"){sentence.type = Sentence::FOR;//第一个分号前面是一个语句sentence.expressions.reserve(2);sentence.sentences.reserve(2);tokens.MoveNextToken(pToken, pos);if (tokens.IsPosNotToken(pos))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "未期待的脚本结束,期待左括号");if (!tokens.IsOperator(pos, "("))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "期待左括号");tokens.MoveNextToken(pToken, pos);if (tokens.IsPosNotToken(pos))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "未期待的脚本结束,期待初始化表达式");Sentence init_sentence;if (!GetSentence(tokens, vars, init_sentence, pToken, pos))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "分析for块的初始化语句出错");sentence.sentences.push_back(init_sentence);if (tokens.IsPosNotToken(pos))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "未期待的脚本结束,期待条件表达式");if (NULL == (pExpression = GetExpression(tokens, vars, NULL, pos, ";")))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "获取条件表达式出错");if (tokens.IsPosNotToken(pos))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "未期待的脚本结束,期待分号");if (!tokens.IsDelimiter(pos, ";"))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "期待分号");sentence.expressions.push_back(*pExpression);tokens.MoveNextToken(pToken, pos);if (tokens.IsPosNotToken(pos))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "未期待的脚本结束,期待循环递增表达式");if (NULL == (pExpression = GetExpression(tokens, vars, NULL, pos, ")")))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "获取循环递增表达式出错");if (tokens.IsPosNotToken(pos))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "未期待的脚本结束,期待右括号");if (!tokens.IsOperator(pos, ")"))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "期待右括号");sentence.expressions.push_back(*pExpression);tokens.MoveNextToken(pToken, pos);Sentence for_sentence;if (!GetSentence(tokens, vars, for_sentence, pToken, pos))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "分析for块的执行语句出错");sentence.sentences.push_back(for_sentence);}else if ("break" == pToken->text){sentence.type = Sentence::BREAK;tokens.MoveNextToken(pToken, pos);if (tokens.IsPosNotToken(pos))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "未期待的脚本结束,期待分号");if (!tokens.IsDelimiter(pos, ";"))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "期待分号");tokens.MoveNextToken(pToken, pos);}else if ("continue" == pToken->text){sentence.type = Sentence::CONTINUE;tokens.MoveNextToken(pToken, pos);if (tokens.IsPosNotToken(pos))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "未期待的脚本结束,期待分号");if (!tokens.IsDelimiter(pos, ";"))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "期待分号");tokens.MoveNextToken(pToken, pos);}else if ("long" == pToken->text || "double" == pToken->text || "int" == pToken->text || "float" == pToken->text || "string" == pToken->text){//声明语句sentence.type = Sentence::DECLARE;Variable var;if ("long" == pToken->text || "int" == pToken->text)var.type = Variable::LONG;else if ("double" == pToken->text || "float" == pToken->text)var.type = Variable::DOUBLE;else var.type = Variable::STRING;tokens.MoveNextToken(pToken, pos);if (tokens.IsPosNotToken(pos))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "未期待的脚本结束,期待变量名");if (tokens.IsDelimiter(pos, ";"))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "未期待的分号,期待变量名");if (pToken->type != Token::IDENTIFIER)CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "期待标识符");sentence.expressions.resize(1);sentence.expressions[0].type = Expression::DEFINE;sentence.expressions[0].VariableName = pToken->text;sentence.expressions[0].m_variable = var;sentence.expressions[0].source_start = sentence.source_start;sentence.expressions[0].source_end = tokens.TokenStart(pos + 1);tokens.MoveNextToken(pToken, pos);if (tokens.IsPosNotToken(pos)){}else if (tokens.IsOperator(pos, "=")){//带有初始值tokens.MoveNextToken(pToken, pos);if (tokens.IsPosNotToken(pos))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "未期待的脚本结束,期待初始化表达式");if (NULL == (pExpression = GetExpression(tokens, vars, NULL, pos, ";")))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "获取初始化表达式出错");if (tokens.IsPosNotToken(pos))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "未期待的脚本结束,期待分号");if (!tokens.IsDelimiter(pos, ";"))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "期待分号");tokens.MoveNextToken(pToken, pos);sentence.expressions[0].AddLeftOperand(*pExpression);}else if (tokens.IsOperator(pos, "(")){//函数for (long i = 0; i < (long)m_functions.size(); ++i){if (m_functions[i].script_name == sentence.expressions[0].VariableName)CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "函数重名");}m_functions.resize(m_functions.size() + 1);CScript* pFunction = &m_functions[m_functions.size() - 1];pFunction->FromParent(*this, sentence.expressions[0].VariableName);pFunction->return_type = var.type;pFunction->count_global_variable = vars.getGlobalCount();tokens.MoveNextToken(pToken, pos);while (!tokens.IsOperator(pos, ")")){Variable param;if ("long" == pToken->text || "int" == pToken->text)param.type = Variable::LONG;else if ("double" == pToken->text || "float" == pToken->text)param.type = Variable::DOUBLE;else if("string"== pToken->text)param.type = Variable::STRING;else CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "期待参数类型");tokens.MoveNextToken(pToken, pos);if (tokens.IsPosNotToken(pos))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "未期待的脚本结束,期待参数名");if (pToken->type != Token::IDENTIFIER)CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "期待标识符");if (!pFunction->m_EnvVariables.AddVariable(pToken->text, param))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "函数参数重名");if (NULL!=vars.FindVariable(pToken->text))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "函数参数与全局变量或环境变量重名");tokens.MoveNextToken(pToken, pos);if (tokens.IsPosNotToken(pos))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "未期待的脚本结束,期待)");if (tokens.IsOperator(pos, ","))tokens.MoveNextToken(pToken, pos);else break;}if (!tokens.IsOperator(pos, ")"))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "期待)");tokens.MoveNextToken(pToken, pos);if (!tokens.IsDelimiter(pos, "{"))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "期待{");tokens.MoveNextToken(pToken, pos);T_VARIABLE_S tmpvars;tmpvars.FromParentVars(vars, pFunction->count_global_variable, &pFunction->m_EnvVariables);if (!pFunction->Build(tokens, tmpvars, pos)){m_msg += "编译失败\r\n";return false;}if (!tokens.IsDelimiter(pos, "}"))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "期待}");tokens.MoveNextToken(pToken, pos);if (!tokens.IsDelimiter(pos, ";"))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "期待分号");tokens.MoveNextToken(pToken, pos);return GetSentence(tokens, vars, sentence, pToken, pos);}else if (!tokens.IsDelimiter(pos, ";")){CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "期待分号,一个语句只能定义一个变量");}}else{CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "非期待的的关键字,是否前面缺少分号?");}break;default:CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "未支持的标记类型");break;}sentence.source_end = tokens.TokenStart(pos);return sentence.source_end != sentence.source_start;}
整个过程通过pos贯穿,pos是当前的Token位置,大部分函数使用的都是pos的引用,在内部会修改pos,函数返回时pos总是处于下一个未处理的Token位置。
二、辅助函数
里面用到一些功能比较小的函数。
2.1 tokens.IsPosNotToken(pos)
这个判断是否pos已经到达结束位置。
2.2 tokens.MoveCurrentToken(pToken, pos)
这个将pToken指向pos处的Token,方便后面使用。
2.3 tokens.IsDelimiter(pos, ";")
这个函数判断pos是否是给定的分隔符,需要同时判断Token类型和文本。
2.4 tokens.MoveNextToken(pToken, pos)
同时将pToken和pos指向下一个Token。
2.5 tokens.IsOperator(pos, "(")
这个函数判断是否是给定的操作符,需要同时判断Token类型和文本。
三、流程分析
流程处理相对简单,根据获取到的第一个Token的类型做分支处理,每个分支根据各自的语法要求获取语句或变量。
如果是标识符、数字、字符串、操作符,就是一个表达式,调用GetExpression()函数获取一个表达式,生成一个表达式语句:
case Token::IDENTIFIER:case Token::NUMBER:case Token::STRING:case Token::OPERATOR:sentence.type = Sentence::EXPRESSION;pExpression = GetExpression(tokens, vars, NULL, pos, ";");if (!tokens.IsPosNotToken(pos) && tokens.IsDelimiter(pos, ";")){tokens.MoveNextToken(pToken, pos);}sentence.expressions.reserve(1);sentence.expressions.push_back(*pExpression);break;
如果是分隔符,只有一种合法类型,“{”,是块语句,循环获取语句直到遇到“}”:
case Token::DELIMITER:if (pToken->text == "{"){sentence.type = Sentence::BLOCK;tokens.MoveNextToken(pToken, pos);while (true){if (tokens.IsPosNotToken(pos))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "未期待的脚本结束,块语句未结束");if (tokens.IsDelimiter(pos, "}")){tokens.MoveNextToken(pToken, pos);break;}Sentence tmpsentence;if (!GetSentence(tokens, vars, tmpsentence, pToken, pos))CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "获取块语句的语句出错");sentence.sentences.reserve(sentence.sentences.size() + 1);sentence.sentences.push_back(tmpsentence);}}else if (pToken->text == "}"){CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "未期待的块语句结束标记");}else if (pToken->text == ";"){sentence.type = Sentence::NULLSENTENCE;tokens.MoveNextToken(pToken, pos);}else{CException::Throw(__FILE__, __LINE__, m_source, tokens.TokenStart(pos), "尚未支持的分隔符");}break;
剩下的就是关键字,对关键字再分别处理,虽然稍微负责一些,但用到的东西和上面的差不多。
剩下的未介绍的部分就是表达式编译了。
(这里是结束,但不是整个系列的结束)