static void FuncRight (void)
/* Handle the .RIGHT function */
{
long Count;
TokList* List;
/* Skip it */
NextTok ();
/* Left paren expected */
ConsumeLParen ();
/* Count argument. Correct negative counts to zero. */
Count = ConstExpression ();
if (Count < 0) {
Count = 0;
}
ConsumeComma ();
/* Read the complete token list */
List = CollectTokens (0, 9999);
/* Delete tokens from the list until Count tokens are remaining */
while (List->Count > (unsigned) Count) {
/* Get the first node */
TokNode* T = List->Root;
/* Remove it from the list */
List->Root = List->Root->Next;
/* Free the node */
FreeTokNode (T);
/* Corrent the token counter */
List->Count--;
}
/* Since we want to insert the list before the now current token, we have
* to save the current token in some way and then skip it. To do this, we
* will add the current token at the end of the token list (so the list
* will never be empty), push the token list, and then skip the current
* token. This will replace the current token by the first token from the
* list (which will be the old current token in case the list was empty).
*/
AddCurTok (List);
/* Insert it into the scanner feed */
PushTokList (List, ".RIGHT");
/* Skip the current token */
NextTok ();
}
static void FuncMid (void)
/* Handle the .MID function */
{
long Start;
long Count;
TokList* List;
/* Skip it */
NextTok ();
/* Left paren expected */
ConsumeLParen ();
/* Start argument. Since the start argument can get negative with
* expressions like ".tcount(arg)-2", we correct it to zero silently.
*/
Start = ConstExpression ();
if (Start < 0 || Start > 100) {
Start = 0;
}
ConsumeComma ();
/* Count argument. Similar as above, we will accept negative counts and
* correct them to zero silently.
*/
Count = ConstExpression ();
if (Count < 0) {
Count = 0;
}
ConsumeComma ();
/* Read the token list */
List = CollectTokens ((unsigned) Start, (unsigned) Count);
/* Since we want to insert the list before the now current token, we have
* to save the current token in some way and then skip it. To do this, we
* will add the current token at the end of the token list (so the list
* will never be empty), push the token list, and then skip the current
* token. This will replace the current token by the first token from the
* list (which will be the old current token in case the list was empty).
*/
AddCurTok (List);
/* Insert it into the scanner feed */
PushTokList (List, ".MID");
/* Skip the current token */
NextTok ();
}
static TokList* CollectRepeatTokens (void)
/* Collect all tokens inside the .REPEAT body in a token list and return
* this list. In case of errors, NULL is returned.
*/
{
/* Create the token list */
TokList* List = NewTokList ();
/* Read the token list */
unsigned Repeats = 0;
while (Repeats != 0 || Tok != TOK_ENDREP) {
/* Check for end of input */
if (Tok == TOK_EOF) {
Error ("Unexpected end of file");
FreeTokList (List);
return 0;
}
/* If we find a token that is equal to the repeat counter name,
* replace it by a REPCOUNTER token. This way we have to do strcmps
* only once for each identifier, and not for each expansion.
* Note: This will fail for nested repeats using the same repeat
* counter name, but
*/
/* Collect all tokens in the list */
AddCurTok (List);
/* Check for and count nested .REPEATs */
if (Tok == TOK_REPEAT) {
++Repeats;
} else if (Tok == TOK_ENDREP) {
--Repeats;
}
/* Get the next token */
NextTok ();
}
/* Eat the closing .ENDREP */
NextTok ();
/* Return the list of collected tokens */
return List;
}
static TokList* CollectTokens (unsigned Start, unsigned Count)
/* Read a list of tokens that is optionally enclosed in curly braces and
* terminated by a right paren. For all tokens starting at the one with index
* Start, and ending at (Start+Count-1), place them into a token list, and
* return this token list.
*/
{
/* Create the token list */
TokList* List = NewTokList ();
/* Determine if the list is enclosed in curly braces. */
token_t Term = GetTokListTerm (TOK_RPAREN);
/* Read the token list */
unsigned Current = 0;
while (CurTok.Tok != Term) {
/* Check for end of line or end of input */
if (TokIsSep (CurTok.Tok)) {
Error ("Unexpected end of line");
return List;
}
/* Collect tokens in the given range */
if (Current >= Start && Current < Start+Count) {
/* Add the current token to the list */
AddCurTok (List);
}
/* Get the next token */
++Current;
NextTok ();
}
/* Eat the terminator token */
NextTok ();
/* If the list was enclosed in curly braces, we do expect now a right paren */
if (Term == TOK_RCURLY) {
ConsumeRParen ();
}
/* Return the list of collected tokens */
return List;
}
static TokList* CollectRepeatTokens (void)
/* Collect all tokens inside the .REPEAT body in a token list and return
* this list. In case of errors, NULL is returned.
*/
{
/* Create the token list */
TokList* List = NewTokList ();
/* Read the token list */
unsigned Repeats = 0;
while (Repeats != 0 || CurTok.Tok != TOK_ENDREP) {
/* Check for end of input */
if (CurTok.Tok == TOK_EOF) {
Error ("Unexpected end of file");
FreeTokList (List);
return 0;
}
/* Collect all tokens in the list */
AddCurTok (List);
/* Check for and count nested .REPEATs */
if (CurTok.Tok == TOK_REPEAT) {
++Repeats;
} else if (CurTok.Tok == TOK_ENDREP) {
--Repeats;
}
/* Get the next token */
NextTok ();
}
/* Eat the closing .ENDREP */
NextTok ();
/* Return the list of collected tokens */
return List;
}
static void FuncLeft (void)
/* Handle the .LEFT function */
{
long Count;
TokList* List;
/* Skip it */
NextTok ();
/* Left paren expected */
ConsumeLParen ();
/* Count argument. Correct negative counts to zero. */
Count = ConstExpression ();
if (Count < 0) {
Count = 0;
}
ConsumeComma ();
/* Read the token list */
List = CollectTokens (0, (unsigned) Count);
/* Since we want to insert the list before the now current token, we have
* to save the current token in some way and then skip it. To do this, we
* will add the current token at the end of the token list (so the list
* will never be empty), push the token list, and then skip the current
* token. This will replace the current token by the first token from the
* list (which will be the old current token in case the list was empty).
*/
AddCurTok (List);
/* Insert it into the scanner feed */
PushTokList (List, ".LEFT");
/* Skip the current token */
NextTok ();
}
