stew

commit 3361dbe483971b71157f1b70c51637a1d0c3d254
parent 8fd86fbed1eacfc1953696dababa9edc42ca1e37
Author: rpa <rpa@laika>
Date:   Sun, 18 Dec 2022 15:43:10 +0000

mu/trk: add jump and return commands

Diffstat:
M
src/mu/trk.c
 | 
35
+++++++++++++++++++++++++++++++++--

1 file changed, 33 insertions(+), 2 deletions(-)
diff --git a/src/mu/trk.c b/src/mu/trk.c
@@ -1,6 +1,5 @@
 /*
 	Primitive sequencer / music-tracker
-
 	reads lines from stdin and prints them at controllable rate
 */
 
@@ -15,7 +14,7 @@ struct List {
 	List *next;
 };
 
-List *list;
+List *list, *rstack[64], **rp = rstack;
 char *file;
 vlong t, dt;
 long bpm = 120, steps = 1;
@@ -38,8 +37,11 @@ struct Cmds {
 	void (*func)(List **, int, char **);
 } cmds[] = {
 	{ "#",    nil       }, /* comment */
+	{ ":",    nil       }, /* label */
 	{ ".bpm", cmdbpm    }, /* update bpm to new value */
 	{ "----", cmdpause  },
+	{ ".jmp", cmdjump   },
+	{ ".ret", cmdret    },
 	{ ".rld", cmdreload }, /* reload file and start from the beginning */
 };
 
@@ -76,6 +78,35 @@ cmdpause(List **, int, char **)
 }
 
 void
+cmdjump(List **lp, int n, char **args)
+{
+	if (n != 2) {
+		fprint(2, "cmdjump: wrong argument count %d\n", n);
+		return;
+	}
+	List *jp = list;
+	while (strcmp(args[1], (char *)jp->v) != 0) {
+		jp = jp->next;
+		if (jp == nil) return;
+	}
+	*rp = (*lp);
+	rp ++;
+	if (rp > rstack + 64) exits("rstack overflow");
+	*lp = jp->next;
+}
+
+void
+cmdret(List **lp, int n, char **)
+{
+	if (n != 1) {
+		fprint(2, "cmdret: too much arguments\n");
+	};
+	rp --;
+	if (rp < rstack) exits("rstack underflow");
+	*lp = (*rp);
+}
+
+void
 cmdreload(List **lp, int, char **)
 {
 	clearlist(list);