/* EBNF: simple-expression ->
* addtivite-expression [relop additivie-expression] */
static TreeNode * simple_expression (void)
{ TreeNode * t = additive_expression();
TreeNode * newNode;
while (token == COMMENT) unexpectedTokenHandling();
/* [relop additive-expression] */
if (isRelop(token))
{ newNode = newExpNode (OpK);
if (newNode != NULL)
{ newNode->child[0] = t;
newNode->attr.op = token;
t = newNode;
}
match (token); // match relop
if (t != NULL)
t->child[1] = additive_expression();
}
return t;
}
// 设已经弹入一个字符，CURRENT_CHAR指向当前待分析的字符（由于可能需要向后看一个字符）
// 试探下一个字符，若是自己的一部分，则读入下一个字符再返回，否则直接返回
Token* Lex_getNextToken(){
Token* tk = (Token*) malloc (sizeof(Token));
tk -> type = TK_UNDEF;
tk ->value = NULL;
while(isSpace(CURRENT_CHAR)){
if(CURRENT_CHAR == '\n')curLine++;
MOVE_NEXT_CHAR;
}
if(CURRENT_CHAR == EOF ){ // 注意先跳过格式字符再看是否EOF，否则文件最后的空格会识别错误
tk -> type = TK_EOF;
// 删除：curLine=0; 原因：造成最后一个错误报告行为0
return tk;
}
if(isAlpha(CURRENT_CHAR)){
int i = 0;
tk -> value = NEW_STRING;
while(isAlpha(CURRENT_CHAR)||isDigit(CURRENT_CHAR)){
APPEND_CHAR(CURRENT_CHAR);
MOVE_NEXT_CHAR;
}
APPEND_CHAR('\0');
// 保留字和标志符的识别
for(i=0;i< KEYWORDS_NUM ;i++){
if(0==strcmp(tk -> value ,keywords[i])){
tk -> type = i; //(tk_e)
free(tk -> value);// 如果是关键字，就释放存储值的空间
return tk;
}
}
tk -> type = TK_IDENT;
return tk;
}
else if(isDigit(CURRENT_CHAR)){ // 无符号整数识别
tk -> value = NEW_STRING;
while(isDigit(CURRENT_CHAR)){
APPEND_CHAR(CURRENT_CHAR);
MOVE_NEXT_CHAR;
}
APPEND_CHAR('\0');
tk -> type = TK_NUM;
return tk;
}
else if(isRelop(CURRENT_CHAR)){
tk -> value = NEW_STRING;
APPEND_CHAR(CURRENT_CHAR);
MOVE_NEXT_CHAR;
if('=' == CURRENT_CHAR){
if(CURRENT_CHAR == '!'){
tk -> type = TK_UNDEF;
}
else {
APPEND_CHAR(CURRENT_CHAR);
MOVE_NEXT_CHAR;
tk -> type = TK_RELOP;
}
}
else {
tk -> type = TK_RELOP; // 2014-7-6 Fixed BUG1
}
APPEND_CHAR('\0');
return tk;
}
else if( '=' == CURRENT_CHAR ){
tk -> value = NEW_STRING;
APPEND_CHAR(CURRENT_CHAR);
MOVE_NEXT_CHAR;
if('=' == CURRENT_CHAR){
APPEND_CHAR(CURRENT_CHAR);
MOVE_NEXT_CHAR;
tk -> type = TK_RELOP;
}
else{
tk -> type = TK_ASSIGN;
}
APPEND_CHAR('\0');
return tk;
}
else {
switch(CURRENT_CHAR){
case '+':tk -> type = TK_ADD;break;
case '-':tk -> type = TK_SUB;break;
case '*':tk -> type = TK_MUL;break;
case '/':tk -> type = TK_DIV;break;
case '{':tk -> type = TK_LBRACE;break;
case '}':tk -> type = TK_RBRACE;break;
case '(':tk -> type = TK_LPAREN;break;
case ')':tk -> type = TK_RPAREN;break;
case ';':tk -> type = TK_SEMICOLON;break;
case '|':tk -> type = TK_LOG_OR;break;
case '&':tk -> type = TK_LOG_AND;break;
default:
tk -> type = TK_UNDEF;
tk -> value = NEW_STRING;
APPEND_CHAR(CURRENT_CHAR);
APPEND_CHAR('\0');
break;
}
MOVE_NEXT_CHAR;
return tk;
}
}
static int isOp (TokenType token)
{ if (isRelop(token)||isAddop(token)||isMulop(token))
return TRUE;
else
return FALSE;
}
void check()
{
char ch;
int i,cur=0;
ch=str[cur];
while(ch!='\0')
{
char token[100];
i=0;
if(isalpha(ch)||ch=='_')
{
while(isalpha(ch)||isdigit(ch)||ch=='_')
{
append(token,ch,i);
i++;
cur++;
ch=str[cur];
}
append(token,'\0',i);
isKey(token);
}
else if(ispunct(ch))
{
if(ch=='<'||ch=='>'||ch=='=')
{
append(token,ch,i);
i++;
cur++;
ch=str[cur];
if(ch=='=')
{
append(token,ch,i);
i++;
cur++;
ch=str[cur];
isRelop(token);
}
else
isRelop(token);
}
else if(ch=='!')
{
append(token,ch,i);
i++;
cur++;
ch=str[cur];
if(ch=='=')
{
append(token,ch,i);
i++;;
cur++;
ch=str[cur];
isRelop(token);
}
else
continue;
}
else if(ch=='('||ch==')'||ch=='{'||ch=='}'||ch=='['||ch==']')
{
isPar(ch);
cur++;
ch=str[cur];
}
else if(ch=='+'||ch=='-'||ch=='*'||ch=='/'||ch=='%'||ch=='^')
{
isOp(ch);
cur++;
ch=str[cur];
}
else if(ch=='"')
{
while(ch!='"')
{
cur++;
ch=str[cur];
}
}
else if(ch==','||ch==';')
{
cur++;
ch=str[cur];
}
}
else if(strncmp(&ch," ",1)==0||ch=='\t'||ch=='\n')
{
while(strncmp(&ch," ",1)==0||ch=='\t'||ch=='\n')
{
cur++;
ch=str[cur];
}
}
else if(isdigit(ch))
{
append(token,ch,i);
i++;
cur++;
ch=str[cur];
while(isdigit(ch))
{
append(token,ch,i);
i++;
cur++;
ch=str[cur];
}
printf("%s\t\tNumeric constant\n",token);
if(ch=='.')
{
append(token,ch,i);
i++;
cur++;
ch=str[cur];
while(isdigit(ch))
{
append(token,ch,i);
i++;
cur++;
ch=str[cur];
}
printf("%s\t\tNumeric constant\n",token);
}
}
else
{
isUndef(ch);
cur++;
ch=str[cur];
}
}
}