implemented the ^Q command for converting between line and glyph positions

* As known from DEC TECO, but extended to convert absolute positions to line numbers as well.
  :^Q returns the current line.
* Especially useful in macros that accept line arguments,
  as it is much shorter than something like
  ^E@ES/LINEFROMPOSITION//+Q.l@ES/POSITIONFROMLINE//:^E-.
* On the other hand, the fact that ^Q checks the line range means we cannot
  easily replace lexer.checkheader with something like
  [:J 0,^Q::S...$ ]:
  Using SCI_POSITIONFROMLINE still has the advantage that it returns `Z` for out-of-bounds ranges
  which would be cumbersome to write with the current ^Q.
* Perhaps there should be a separate command for converting between absolute lines and positions
  and :^Q should be repurposed to return a failure boolean for out-of-range values?
* fnkeys.tes could be simplified.

1 files changed, 6 insertions, 6 deletions

diff --git a/lib/fnkeys.tes b/lib/fnkeys.tes
index fd6b332..ab78025 100644
--- a/lib/fnkeys.tes
+++ b/lib/fnkeys.tes
@@ -36,7 +36,7 @@
  *!
 
 @[HOME]{
-  ESLINEFROMPOSITIONESPOSITIONFROMLINE:U.p
+  0+.U.p
   Q.pU.l <Q.l-."U 1; ' Q.l-.AU.c Q.c- "N Q.c-9"N Q.lU.p 1; '' %.l>
   Q.pESGETCOLUMN,4EJ
   Q.p-.M#c
@@ -45,7 +45,7 @@
 1U[HOME]
 
 @[END]{
-  ESLINEFROMPOSITIONESGETLINEENDPOSITIONU.p
+  :-1ESGETLINEENDPOSITIONU.p
   Q.pESGETCOLUMN,4EJ
   Q.p:-.M#c
 }
@@ -54,7 +54,7 @@
 
 @[NPAGE]{
   0,4EJ
-  ESLINEFROMPOSITION+(ESLINESONSCREEN)
+  :-1+ESLINESONSCREEN
   ESPOSITIONFROMLINEU.p
   Q.p"< Z | Q.p: '-.M#c
 }
@@ -63,7 +63,7 @@
 
 @[PPAGE]{
   0,4EJ
-  ESLINEFROMPOSITION-(ESLINESONSCREEN)U.l
+  :-1-ESLINESONSCREENU.l
   Q.l"< 0 | Q.lESPOSITIONFROMLINE: '-.M#c
 }
 @[PPAGE]{(M[PPAGE]}
@@ -102,13 +102,13 @@
 1U[SRIGHT]
 
 @[UP]{
-  4EJ(ESLINEFROMPOSITION-1)ESFINDCOLUMN:-.M#c
+  4EJ,:-2ESFINDCOLUMN:-.M#c
 }
 @[UP]{(M[UP]}
 1U[UP]
 
 @[DOWN]{
-  4EJ(ESLINEFROMPOSITION+1)ESFINDCOLUMN:-.M#c
+  4EJ,:ESFINDCOLUMN:-.M#c
 }
 @[DOWN]{(M[DOWN]}
 1U[DOWN]