properly document some functions in expressions.c and simplified code

* Practically all calls to teco_expressions_args() must be preceded by teco_expressions_eval().
* In code paths where we know that teco_expressions_args() > 0, it is safe
  to call teco_expressions_pop_num(0) instead of teco_expressions_pop_num_calc().
  This is both easier and faster.
* teco_expressions_pop_num_calc() is for simple applications where you just want to get
  a command argument with default (implied) values.
  Since it includes teco_expressions_eval(), we can avoid superfluous calls.
* -EC...$ turned out to be broken and is fixed now.
  A test case has been added.

1 files changed, 4 insertions, 9 deletions

diff --git a/src/move-commands.c b/src/move-commands.c
index 5c2159e..cf5d6b0 100644
--- a/src/move-commands.c
+++ b/src/move-commands.c
@@ -620,21 +620,16 @@ teco_state_start_delete_chars(teco_machine_main_t *ctx, GError **error)
 void
 teco_state_control_lines2glyphs(teco_machine_main_t *ctx, GError **error)
 {
-	if (!teco_expressions_eval(FALSE, error))
-		return;
-
 	if (teco_machine_main_eval_colon(ctx)) {
 		gssize pos;
 
+		if (!teco_expressions_eval(FALSE, error))
+			return;
+
 		if (!teco_expressions_args()) {
 			pos = teco_interface_ssm(SCI_GETCURRENTPOS, 0, 0);
 		} else {
-			teco_int_t v;
-
-			if (!teco_expressions_pop_num_calc(&v, 0, error))
-				return;
-
-			pos = teco_interface_glyphs2bytes(v);
+			pos = teco_interface_glyphs2bytes(teco_expressions_pop_num(0));
 			if (pos < 0) {
 				teco_error_range_set(error, "^Q");
 				return;