int isWhileStructure() {
char token[TOKEN_SIZE];
strcpy(token, nextToken());
upper(token);
if (hasNextToken() && strcmp(token, "NOT") != 0) {
reportError(1, "expected NOT");
return 0;
}
strcpy(token, nextToken());
upper(token);
if (strcmp(token, "DETECTMARKER") != 0) {
reportError(2, "expected DETECTMARKER");
return 0;
}
strcpy(token, nextToken());
upper(token);
if (strcmp(token, "DO") != 0) {
reportError(3, "expected DO");
return 0;
}
int errorIndex = isCommaSeperatedCommands();
if (!errorIndex) return 1;
if (errorIndex < 0) reportError(3-errorIndex, "command list must terminate with END command");
reportError(errorIndex+3, "not a valid comma seperated list of commands");
return 0;
}
void reportError(int errorIndex, char *error) {
myRewind();
for (int i=0; i<errorIndex; i++) {
printf("%s ", nextToken());
}
if (hasNextToken()) {
printf("***%s ", nextToken());
} else {
printf("*** ");
}
while(hasNextToken()) {
printf("%s ", nextToken());
}
printf("\nError: %s, ", error);
}
int isString() {
char token[TOKEN_SIZE];
strcpy(token, nextToken());
if (token[0] != '\"') {
reportError(1, "expected a string beginning with \"");
return 0;
}
while (hasNextToken()) {
strcpy(token, nextToken());
}
if (token[strlen(token)-1] != '\"') {
reportError(1, "expected a string ending with \"");
return 0;
}
return 1;
}
std::string StringTokenizer::nextToken(){
if(!hasNextToken()){
return "";
}
if(pos==str.length()){
pos++;
return "";
}
size_t nextPos = str.find_first_of(delims, pos);
if(nextPos==std::string::npos){
std::string res = str.substr(pos);
pos = str.length()+1;
return res;
}
std::string res = str.substr(pos,nextPos-(pos));
pos = nextPos+1;
return res;
}
int isValidExpression(char *expression) {
initBuffer(expression);
char token[TOKEN_SIZE];
if (hasNextToken()) {
strcpy(token, nextToken());
} else return 0;
upper(token);
if (strcmp(token, "REPEAT") == 0) return isRepeatStructure();
if (strcmp(token, "WHILE") == 0) return isWhileStructure();
if (strcmp(token, "SAY") == 0) return isString();
if (isValidCommand(token)) return 1;
reportError(0, "not a valid expression");
return 0;
}
/** "Returns 1 if the expression agrees with one of the legal robot expressions,
otherwise it returns 0."
<p>
"Expression" is a line, not in individal token. It checks the individual
tokens, and then it checks the syntax of the line. If it returns false, it's
guaranteed to set synax.error.
<p>
It uses parse.c to tokenise, so it will destroy any temp data that you have. */
int isValidExpression(const char *const expression) {
const struct Token *token;
int shift;
char avatar[512] = "", *a, *b;
/* check the arguments */
if(!expression) {
snprintf(syntax.error, sizeof syntax.error, "null expression");
syntax.index = -1;
return 0;
}
/* parse expression into Tokens and put them into the avatar (expression
buffer or whatever) */
initBuffer(expression);
a = avatar;
while(hasNextToken()) {
if(!(token = match_token(nextToken()))) return 0;
/* danger! (undefined behaviour)
snprintf(avatar, sizeof avatar, "%s%c", avatar, token->avatar) */
if(a >= avatar + sizeof avatar / sizeof(char) - 1 /*null*/) {
snprintf(syntax.error, sizeof syntax.error,
"line too long; %u tokens", (int)sizeof avatar);
/* index is set in parse.c */
return 0;
}
*(a++) = token->avatar;
*a = '\0';
}
if(debug) fprintf(stderr, "isValidExp avatar before <%s>\n", avatar);
/* group tokens together; it could have been combined with the previous
step for greater effecacity, but more confusion */
while((b = strrchr(avatar, 'E'))) {
for(a = b - 1; a >= avatar && *a == '$'; a--); a++;
for(shift = b - a, *(a++) = '%'; (*a = *(a + shift)); a++);
}
if(debug) fprintf(stderr, "isValidExp avatar grouping <%s>\n", avatar);
return match_expression(avatar) ? 1 : 0;
}
int isCommaSeperatedCommands() {
while (hasNextToken()) {
char token[80];
int i=0;
strcpy(token, nextToken());
upper(token);
if (token[strlen(token)-1] == ',') {
char command_token[80];
strncpy(command_token, token, strlen(token)-1);
command_token[strlen(token)-1] = '\0';
if (!isValidCommand(command_token)) return i;
i++;
} else {
if (!isValidCommand(token)) return i;
char *end_token = nextToken();
upper(end_token);
if (strcmp(end_token, "END") != 0) return -i;
break;
}
}
return 0;
}
