# HG changeset patch
# User John Tsiombikas <nuclear@member.fsf.org>
# Date 1426457634 -7200
# Node ID ae1c30fa39f389b57ce48802e0c3bb70c4459884
# Parent  f167a743f34820cb29fc2f2e55fbae07f809b31c
working on the control structures of tutorial5

diff -r f167a743f348 -r ae1c30fa39f3 src/main.c
--- a/src/main.c	Sun Mar 15 13:48:04 2015 +0200
+++ b/src/main.c	Mon Mar 16 00:13:54 2015 +0200
@@ -12,11 +12,16 @@
 };
 
 void init(void);
+void program(void);
+void block(void);
+void doif(void);
+void dowhile(void);
+void condition(void);
 void expression(void);
 void assignment(void);
 void term(void);
 void factor(void);
-void ident();
+void ident(void);
 void add(void);
 void sub(void);
 void mul(void);
@@ -33,6 +38,10 @@
 void emitln(const char *fmt, ...);
 int is_addsub(char c);
 int add_symbol(char c, int type);
+int newlabel(void);
+const char *labelstr(int lb);
+void postlabel(int lb);
+void other(void);
 
 FILE *infile, *outfile;
 char look;
@@ -60,10 +69,7 @@
 	/* output prologue */
 	fputs(prologue, outfile);
 
-	assignment();
-	if(look != '\n') {
-		expected("newline");
-	}
+	program();
 
 	/* output epilogue */
 	fputs(epilogue, outfile);
@@ -86,6 +92,84 @@
 	skip_white();
 }
 
+void program(void)
+{
+	block();
+	if(look != 'e') {
+		expected("End");
+	}
+	emitln("# END");
+}
+
+void other(void)
+{
+	emitln("%c", get_name());
+}
+
+void block(void)
+{
+	while(look != 'e' && look != 'l') {
+		switch(look) {
+		case 'i':
+			doif();
+			break;
+
+		case 'w':
+			dowhile();
+			break;
+
+		default:
+			other();
+			break;
+		}
+	}
+}
+
+void doif(void)
+{
+	int lb1, lb2;
+
+	match('i');
+	condition();
+
+	lb1 = newlabel();
+	lb2 = lb1;
+
+	emitln("jz %s", labelstr(lb1));
+	block();
+
+	if(look == 'l') {
+		match('l');
+		lb2 = newlabel();
+		emitln("jmp %s", labelstr(lb2));
+		postlabel(lb1);
+		block();
+	}
+	match('e');
+	postlabel(lb2);
+}
+
+void dowhile(void)
+{
+	int lbtop, lbend;
+
+	match('w');
+	lbtop = newlabel();
+	lbend = newlabel();
+	postlabel(lbtop);
+	condition();
+	emitln("jz %s", labelstr(lbend));
+	block();
+	match('e');
+	emitln("jmp %s", labelstr(lbtop));
+	postlabel(lbend);
+}
+
+void condition(void)
+{
+	emitln("<condition>");
+}
+
 void expression(void)
 {
 	if(is_addsub(look)) {
@@ -149,7 +233,7 @@
 	}
 }
 
-void ident()
+void ident(void)
 {
 	char name = get_name();
 	if(look == '(') {
@@ -320,3 +404,21 @@
 	symlist = sym;
 	return 0;
 }
+
+int newlabel(void)
+{
+	static int n;
+	return n++;
+}
+
+const char *labelstr(int lb)
+{
+	static char buf[16];
+	sprintf(buf, "L%02d", lb);
+	return buf;
+}
+
+void postlabel(int lb)
+{
+	fprintf(outfile, "%s:\n", labelstr(lb));
+}