Allow functions in any term, fix bug in string escape parsing

src/expr.c

@@ -17,14 +17,16 @@
 /* Push Term and Operator onto Stack */
 void pshtrm(void) {
   if (trmidx >= MAXTRM) ERROR("Maximum Function Call/Array Index Depth Exceeded", 0, EXIT_FAILURE)
-  oprstk[trmidx] = oper; 
-  strcpy(trmstk[trmidx++], term);
+  oprstk[trmidx] = oper;          //Save Operator
+  typstk[trmidx] = valtyp;        //Save Value Type
+  strcpy(trmstk[trmidx++], term); //Save Term
 }
 
 /* Pop Term and Operator off Stack */
 void poptrm(void) {
-  strcpy(term, trmstk[--trmidx]);
-  oper = oprstk[trmidx];
+  strcpy(term, trmstk[--trmidx]); //Restore Term
+  valtyp = typstk[trmidx];        //Restore Value Type
+  oper = oprstk[trmidx];          //Restore Operator
 }
 
 /* Parse value (literal or identifier)  *
@@ -100,15 +102,34 @@ void chkidx(void) {
   }
 }
 
+/* Process Function in Term */
+void prcfnc(void) {
+  asmlin("PHA", "");       //Save Accumulator
+  prsfnc(0);               //Parse Function Call
+  asmlin("PHA", "");       //Push Result of Function Call onto Stack
+  asmlin("TSX", "");       //X will be one byte before Result
+  asmlin("LDA", "$102,X"); //Get Original Accumulator Value from Stack
+  strcpy(term, "$101,X");  //Set Term to Return Value on Stack
+}
+
+/* Post Function Call Processing */
+void pstfnc(void) {
+  asmlin("INX", ""); //Increment Past Return Value
+  asmlin("INX", ""); //Increment Past Saved Accumutator Value
+  asmlin("TXS", ""); //Return Stack Pointer to Original State
+}
+
 /* Parse Term in Expression           *
  * Sets: term - the term (as a string) */
 void prstrm(void) {
   DEBUG("Parsing term\n", 0)
   prsval(FALSE);
-  if (valtyp == FUNCTION) ERROR("Function call only allowed in first term\n", 0, EXIT_FAILURE)
   strcpy(term, value);
   DEBUG("Parsed term %s\n", term)
-  chkidx();  //Check for Array Index
+  strcpy(term, value);
+  DEBUG("Parsed term %s\n", term)
+  if (valtyp == FUNCTION) prcfnc(); //Process Function Call
+  else chkidx();  //Check for Array Index
   skpspc();
 }
 
@@ -220,6 +241,7 @@ void prsrxp(char trmntr) {
     prsopr(); //Parse Operator
     prstrm(); //Parse Term
     prcopr(); //Process Operator
+	if (valtyp == FUNCTION) pstfnc(); //Do Post Function Processing
 	trmcnt--;
   } 
   expect(trmntr);

src/expr.h

@@ -6,6 +6,7 @@ char term[255]; //Term parsed from equation
 
 char oprstk[MAXTRM];	         //Operator Stack
 char trmstk[MAXTRM][VARLEN+1];   //Function/Index Terms Stack
+int  typstk[MAXTRM];             //Value Type Stack
 int  trmidx;                     //Next Index in Stack
 
 int  trmcnt;  //Number of total terms in current expression

src/parse.c

@@ -139,6 +139,7 @@ void getwrd(void) {
 char escape(char c) {
   DEBUG("Escaping character '%c'\n", c)
   switch (c) {
+    case 'n': return 0x0a;
     case 'r': return 0x0d;
     default: return c;
   }
@@ -151,7 +152,7 @@ void getstr(void) {
   DEBUG("Parsing string\n", 0)
   strdel = getnxt();  //Get String Delimiter
   CCMNT(strdel);
-  while(match(strdel) == escnxt) {
+  while(!match(strdel) || escnxt) {
     CCMNT(nxtchr);
     if (escnxt) {
       word[wrdlen++] = escape(getnxt());