feature: add variable++ and variable-- increment/decrement notation

Author: msaarna

keywords.c

@@ -306,6 +306,8 @@ void keywords (char **cstatement)
 	i = 0;
 	removeCR (statement[0]);
 	removeCR (statement[1]);
+	removeCR (statement[2]);
+	removeCR (statement[3]);
 	if (!strncmp (statement[0], "return", 7))
 	    prerror ("return used as label");
 	else if (statement[1][0] == '\0')
@@ -534,6 +536,10 @@ void keywords (char **cstatement)
 	    let (statement);
 	else if (!strncmp (statement[1], "dec", 4))
 	    dec (statement);
+	else if ((statement[2][0]=='+')&&(statement[3][0]=='+'))
+	    increment (statement);
+	else if ((statement[2][0]=='-')&&(statement[3][0]=='-'))
+	    decrement (statement);
 	else if (!strncmp (statement[1], "macro", 6))
 	    domacro (statement);
 	else if (!strncmp (statement[1], "callmacro", 10))

statements.c

@@ -9687,6 +9687,24 @@ void displayoperation (char *opcode, char *operand, int index)
     }
 }
 
+void increment (char **statement)
+{
+    //   1        2    3
+    // variable  "+"  "+"
+
+    assertminimumargs (statement, "increment notation", 2);
+    printf ("  inc %s\n", statement[1]);
+}
+
+void decrement (char **statement)
+{
+    //   1        2    3
+    // variable  "-"  "-"
+
+    assertminimumargs (statement, "decrement notation", 2);
+    printf ("  dec %s\n", statement[1]);
+}
+
 void dec (char **cstatement)	// "dec" is variation of "let" that uses decimal mode
 {
     decimal = 1;

statements.h

@@ -107,6 +107,8 @@ void pokechar (char **);
 void setfade (char **statement);
 void let (char **);
 void dec (char **);
+void increment (char **);
+void decrement (char **);
 void bank (char **);
 void dmahole (char **);
 void rem (char **);