vis: shadow default register while in prompt mode

Editing operation in prompt mode should not affect the default
register.

2 files changed, 12 insertions, 2 deletions

diff --git a/vis-modes.c b/vis-modes.c
index 6e2e196..ea539f1 100644
--- a/vis-modes.c
+++ b/vis-modes.c
@@ -100,13 +100,22 @@ static void vis_mode_prompt_input(Vis *vis, const char *str, size_t len) {
 }
 
 static void vis_mode_prompt_enter(Vis *vis, Mode *old) {
-	if (old->isuser && old != &vis_modes[VIS_MODE_PROMPT])
+	if (old->isuser && old != &vis_modes[VIS_MODE_PROMPT]) {
 		vis->mode_before_prompt = old;
+		/* prompt manipulations e.g. <Backspace> should not affect default register */
+		Register tmp = vis->registers[VIS_REG_PROMPT];
+		vis->registers[VIS_REG_PROMPT] = vis->registers[VIS_REG_DEFAULT];
+		vis->registers[VIS_REG_DEFAULT] = tmp;
+	}
 }
 
 static void vis_mode_prompt_leave(Vis *vis, Mode *new) {
-	if (new->isuser)
+	if (new->isuser) {
 		vis_prompt_hide(vis);
+		Register tmp = vis->registers[VIS_REG_DEFAULT];
+		vis->registers[VIS_REG_DEFAULT] = vis->registers[VIS_REG_PROMPT];
+		vis->registers[VIS_REG_PROMPT] = tmp;
+	}
 }
 
 static void vis_mode_insert_enter(Vis *vis, Mode *old) {
diff --git a/vis.h b/vis.h
index 8dee46b..2834fbd 100644
--- a/vis.h
+++ b/vis.h
@@ -350,6 +350,7 @@ enum VisRegister {
 	VIS_REG_u, VIS_REG_v, VIS_REG_w, VIS_REG_x, VIS_REG_y,
 	VIS_REG_z,
 	VIS_REG_DEFAULT, /* used when no other register is specified */
+	VIS_REG_PROMPT,  /* internal register which shadows DEFAULT in PROMPT mode */
 	VIS_REG_INVALID, /* has to be the last enum member */
 };