From b81f7b3ecb4638a645d2fdbabf6a7cf3edb25730 Mon Sep 17 00:00:00 2001
From: Joshua Bell <inexorabletash@gmail.com>
Date: Sun, 7 Jun 2020 08:02:08 -0700
Subject: [PATCH] Allow prefixes which as BASIC tokens

---
 Makefile                   |  6 ++++--
 README.md                  | 19 +++++++++----------
 vols.cmd.s => online.cmd.s |  0
 package.sh                 |  2 +-
 path.s                     | 24 +++++++++++++++---------
 5 files changed, 29 insertions(+), 22 deletions(-)
 rename vols.cmd.s => online.cmd.s (100%)

diff --git a/Makefile b/Makefile
index d7bc619..4470e6f 100644
--- a/Makefile
+++ b/Makefile
@@ -5,9 +5,9 @@ LDFLAGS = --config apple2-asm.cfg
 OUTDIR = out
 
 TARGETS = $(OUTDIR)/path.BIN \
-	$(OUTDIR)/bell.CMD $(OUTDIR)/hello.CMD $(OUTDIR)/echo.CMD $(OUTDIR)/vols.CMD
+	$(OUTDIR)/bell.CMD $(OUTDIR)/hello.CMD $(OUTDIR)/echo.CMD $(OUTDIR)/online.CMD
 
-.PHONY: clean all
+.PHONY: clean all package
 all: $(OUTDIR) $(TARGETS)
 
 $(OUTDIR):
@@ -20,6 +20,8 @@ clean:
 	rm -f $(OUTDIR)/*.list
 	rm -f $(TARGETS)
 
+package:
+	./package.sh
 
 $(OUTDIR)/%.o: %.s $(HEADERS)
 	ca65 $(CAFLAGS) $(DEFINES) --listing $(basename $@).list -o $@ $<
diff --git a/README.md b/README.md
index 7f594c4..6be3dd4 100644
--- a/README.md
+++ b/README.md
@@ -2,11 +2,8 @@
 
 [![Build Status](https://travis-ci.org/a2stuff/prodos-path.svg?branch=master)](https://travis-ci.org/a2stuff/prodos-path)
 
-
 💾 Disk images can be found on the [Releases](https://github.com/a2stuff/prodos-path/releases) page 💾
 
-
-
 Build with [ca65](https://cc65.github.io/doc/ca65.html)
 
 Installation:
@@ -33,19 +30,21 @@ Example:
 /hd/cmds
 ] BELL                   - will invoke /hd/cmds/BELL if present
 ] HELLO                  - will invoke /hd/cmds/HELLO if present
-] VOLS                   - will invoke /hd/cmds/VOLS if present
+] ONLINE                 - will invoke /hd/cmds/ONLINE if present
 ```
 
 Notes:
-* Allocates a permanent buffer to store the code and path (2 pages)
-* Can be invoked as lower case (e.g. `path ...`)
-* Applesoft BASIC commands are unaffected (but can't be CMD names)
 * Search order when a command is typed:
    * ProDOS BASIC.SYSTEM intrinsics (`CAT`, `PREFIX`, etc)
-   * AppleSoft keywords (`LIST`, `PRINT`, etc)
+   * BASIC keywords (`LIST`, `PRINT`, etc)
    * CMD files in paths, in listed order
+* Allocates a permanent buffer to store the code and path (2 pages)
+* `PATH` can be invoked as lower case (e.g. `path /DISK/CMDS`)
+* Commands can be invoked as lower case (e.g. `hello`)
+* Applesoft BASIC commands are unaffected (but can't be CMD names)
+   * Commands with BASIC keywords as _prefixes_ are allowed as long as the command continues with an alphabetic character. For example, `ONLINE` is allowed despite conflicting with the valid BASIC statement `ONLINE GOTO10` which is short for `ON LINE GOTO 10`.
 
-Sample commands:
+Sample commands included:
 * `BELL` - beeps the speaker
 * `HELLO` - shows a short message
-* `VOLS` - lists online volumes (volume name, slot and drive)
+* `ONLINE` - lists online volumes (volume name, slot and drive)
diff --git a/vols.cmd.s b/online.cmd.s
similarity index 100%
rename from vols.cmd.s
rename to online.cmd.s
diff --git a/package.sh b/package.sh
index c75d77a..3757c6c 100755
--- a/package.sh
+++ b/package.sh
@@ -21,7 +21,7 @@ add_file "out/path.BIN" "path#062000"
 add_file "out/bell.CMD" "bell#F04000"
 add_file "out/echo.CMD" "echo#F04000"
 add_file "out/hello.CMD" "hello#F04000"
-add_file "out/vols.CMD" "vols#F04000"
+add_file "out/online.CMD" "online#F04000"
 
 rm -r "$PACKDIR"
 
diff --git a/path.s b/path.s
index ea82bf8..21a057e 100644
--- a/path.s
+++ b/path.s
@@ -245,7 +245,18 @@ next_char:
         sbc     (tptr),Y
         beq     mloop
         cmp     #$80          ; If only difference was the high bit
-        beq     not_ours      ; then it's end-of-token -- and a match!
+        bne     next_token    ; then it's end-of-token -- and a match!
+
+        ;; Only if next command char is not alpha.
+        ;; This allows 'ON' as a prefix (e.g. 'ONLINE'),
+        ;; without preventing 'RUN100' from being typed.
+
+        inx
+        jsr     to_upper_ascii
+        cmp     #'A'
+        bcc     not_ours
+        cmp     #'Z'+1
+        bcs     not_ours
 
         ;; Otherwise, advance to next token
 next_token:
@@ -262,6 +273,7 @@ sloop:  lda     (tptr),y         ; Scan table looking for a high bit set
         beq     maybe_invoke
 
 not_ours:
+fail_invoke:
         sec                     ; Signal failure...
         next_command := *+1
         jmp     $ffff           ; Execute next command in chain
@@ -269,11 +281,6 @@ not_ours:
 
 ;;; ============================================================
 
-fail_invoke:
-        sec
-        rts
-
-
 maybe_invoke:
 
         ppos := $D6             ; position into path_buffer
@@ -409,9 +416,8 @@ notok:  dey
 
 fail_load:
         jsr     FREEBUFR
-        lda     #8              ; I/O ERROR - TODO: is this used???
-        sec
-        rts
+        reloc_point *+2
+        jmp     fail_invoke
 
 ;;; ============================================================
 ;;; ============================================================