5 files changed, 78 insertions, 8 deletions

diff --git a/src/frame.c b/src/frame.c
index fb849a4..32de26e 100644
--- a/src/frame.c
+++ b/src/frame.c
@@ -861,6 +861,60 @@ static __attribute__((unused)) void show_para(Paragraph *p)
 }
 
 
+void merge_paragraphs(struct frame *fr, int para)
+{
+	Paragraph *p1, *p2;
+	struct text_run *runs_new;
+	int i;
+	size_t len;
+	SCBlock *scblock;
+
+	if ( para >= fr->n_paras-1 ) {
+		printf("Paragraph number too high to merge.\n");
+		return;
+	}
+
+	p1 = fr->paras[para];
+	p2 = fr->paras[para+1];
+	show_para(p1);
+	show_para(p2);
+
+	if ( (p1->type != PARA_TYPE_TEXT) || (p2->type != PARA_TYPE_TEXT) ) {
+		printf("Trying to merge non-text paragraphs.\n");
+		return;
+	}
+
+	/* All the runs from p2 get added to p1 */
+	runs_new = realloc(p1->runs,
+	                   (p1->n_runs+p2->n_runs)*sizeof(struct text_run));
+	if ( runs_new == NULL ) {
+		fprintf(stderr, "Failed to allocate merged runs.\n");
+		return;
+	}
+	p1->runs = runs_new;
+
+	/* Take off the newline at the end of the last run */
+	scblock = p1->runs[p1->n_runs-1].scblock;
+	len = p1->runs[p1->n_runs-1].len_bytes--;
+	if ( sc_block_contents(scblock)[len+1] != '\n' ) {
+		fprintf(stderr, "Whoops, not a newline!\n");
+	}
+	scblock_delete_text(scblock, len+1, len+2);
+
+	for ( i=0; i<p2->n_runs; i++ ) {
+		p1->runs[p1->n_runs++] = p2->runs[i];
+	}
+	free(p2->runs);
+	free(p2);
+	show_para(p1);
+
+	for ( i=para+1; i<fr->n_paras-1; i++ ) {
+		fr->paras[i] = fr->paras[i+1];
+	}
+	fr->n_paras--;
+}
+
+
 static char *s_strdup(const char *a)
 {
 	if ( a == NULL ) return NULL;
diff --git a/src/frame.h b/src/frame.h
index 0eb562b..3f343dc 100644
--- a/src/frame.h
+++ b/src/frame.h
@@ -164,4 +164,6 @@ extern int get_sc_pos(struct frame *fr, int pn, size_t pos,
 
 extern void *get_para_bvp(Paragraph *para);
 
+extern void merge_paragraphs(struct frame *fr, int para);
+
 #endif	/* FRAME_H */
diff --git a/src/sc_editor.c b/src/sc_editor.c
index 37bba88..748089e 100644
--- a/src/sc_editor.c
+++ b/src/sc_editor.c
@@ -603,22 +603,24 @@ static void do_backspace(struct frame *fr, SCEditor *e)
 	size_t new_pos = old_pos;
 	int new_trail = old_trail;
 
+	double wrapw = e->cursor_frame->w - e->cursor_frame->pad_l
+	                - e->cursor_frame->pad_r;
+
 	Paragraph *para = e->cursor_frame->paras[old_para];
 
 	cursor_moveh(e->cursor_frame, &new_para, &new_pos, &new_trail, -1);
 	cursor_moveh(e->cursor_frame, &e->cursor_para, &e->cursor_pos,
 	             &e->cursor_trail, -1);
 	if ( e->cursor_para != old_para ) {
-		/* FIXME: Implement this case */
-		printf("Merge paragraphs!\n");
-		return;
-	}
+		merge_paragraphs(e->cursor_frame, e->cursor_para);
+		wrap_paragraph(e->cursor_frame->paras[new_para], NULL, wrapw);
+	} else {
 
-	delete_text_in_paragraph(para, e->cursor_pos+e->cursor_trail,
-	                         old_pos+old_trail);
+		delete_text_in_paragraph(para, e->cursor_pos+e->cursor_trail,
+		                         old_pos+old_trail);
+		wrap_paragraph(para, NULL, wrapw);
+	}
 
-	wrap_paragraph(para, NULL, e->cursor_frame->w - e->cursor_frame->pad_l
-	                            - e->cursor_frame->pad_r);
 
 	sc_editor_redraw(e);
 }
diff --git a/src/sc_parse.c b/src/sc_parse.c
index 689a31e..8bc6578 100644
--- a/src/sc_parse.c
+++ b/src/sc_parse.c
@@ -631,6 +631,16 @@ void sc_insert_block(SCBlock *b1, int o1, SCBlock *ins)
 }
 
 
+void scblock_delete_text(SCBlock *b, size_t o1, size_t o2)
+{
+	if ( o1 >= o2 ) {
+		fprintf(stderr, "Backwards delete!\n");
+		return;
+	}
+	memmove(b->contents+o1, b->contents+o2, o2-o1);
+}
+
+
 static void delete_from_block(SCBlock *b, int o1, int o2)
 {
 	if ( o1 == o2 ) return;  /* nothing to delete */
diff --git a/src/sc_parse.h b/src/sc_parse.h
index 1260cc0..c9150eb 100644
--- a/src/sc_parse.h
+++ b/src/sc_parse.h
@@ -74,4 +74,6 @@ extern void show_sc_block(const SCBlock *bl, const char *prefix);
 extern char *serialise_sc_block(const SCBlock *bl);
 extern void save_sc_block(FILE *fh, const SCBlock *bl);
 
+extern void scblock_delete_text(SCBlock *b, size_t o1, size_t o2);
+
 #endif	/* SC_PARSE_H */